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Prolonged expiration down to residual volume leads to severe arterial hypoxemia in athletes during submaximal exercise
Abstract
The goal of this study was to assess the effects of a prolonged expiration (PE) carried out down to the residual volume (RV) during a submaximal exercise and consider whether it would be worth including this respiratory technique in a training programme to evaluate its effects on performance. Ten male triathletes performed a 5-min exercise at 70% of maximal oxygen consumption in normal breathing (NB(70)) and in PE (PE(70)) down to RV. Cardiorespiratory parameters were measured continuously and an arterialized blood sampling at the earlobe was performed in the last 15s of exercise. Oxygen consumption, cardiac frequency, end-tidal and arterial carbon dioxide pressure, alveolar-arterial difference for O(2) (PA(O2) - Pa(O2)) and P(50) were significantly higher, and arterial oxygen saturation (87.4+/-3.4% versus 95.0+/-0.9%, p<0.001), alveolar (PA(O2)) or arterial oxygen pressure, pH and ventilatory equivalent were significantly lower in PE(70) than NB(70). There was no difference in blood lactate between exercise modalities. These results demonstrate that during submaximal exercise, a prolonged expiration down to RV can lead to a severe hypoxemia caused by a PA(O2) decrement (r=0.56; p<0.05), a widened PA(O2) - Pa(O2) (r=-0.85; p<0.001) and a right shift of the oxygen dissociation curve (r=-0.73; p<0.001).
... These include regulating the composition of inhaled air using various types of breathing manipulations. Woorons et al. (2007) used an apneas cycle during submaximal exercise to induce hypoxemia, leading to delayed metabolic acidosis and increased exercise performance. In addition, exercise in hypoxia is thought to produce compensatory vasodilation with an induced nitric oxide-dependent increase in muscle blood flow (Casey and Joyner, 2012). ...
... Induction of hypercapnia prior to exercise is thought to elicit a sympathetic response leading to increased tidal volume (VT) and increased blood flow to skeletal muscle in a manner that may improve exercise performance. In turn, increased partial pressure of carbon dioxide (pCO 2 ) in the body increases the concentration of bicarbonate in the blood (Woorons et al., 2007(Woorons et al., , 2010. This may affect buffering capacity and may be beneficial for pH regulation and stimulating anaerobic metabolic efficiency, especially during intense exercise, e.g., repeated sprints (Trincat et al., 2017). ...
... Yamamoto et al. (1988) reported a greater increase in blood lactate during restitution after hypoventilation induced by reducedfrequency breathing (RFB), compared to normal breathing. Woorons et al. (2007) had similar observations in their study, demonstrating delayed lactate efflux from active muscles during prolonged expiration (PE) exercise. Prolonged release of the lactate ions may alter the glycolysis state and induce higher concentrations in working muscles, without its concomitant presence in the blood. ...
Special breathing exercises performed during warm-up lead to hypercapnia and stimulation of mechanisms leading to increased exercise performance, but the effect of a device that increases the respiratory dead space volume (ARDSv) during warm-up has not been studied. The purpose of this study was to investigate the effect of 10 min warm-up with ARDSv on performance, physiological and biochemical responses during sprint interval cycling exercise (SIE). During four laboratory visits at least 72 h apart, they completed: (1) an incremental exercise test (IET) on a cycloergometer, (2) a familiarization session, and cross-over SIE sessions conducted in random order on visits (3) and (4). During one of them, 1200 mL of ARDSv was used for breathing over a 10-min warm-up. SIE consisted of 6 × 10-s all-out bouts with 4-min active recovery. Work capacity, cardiopulmonary parameters, body temperature, respiratory muscle strength, blood acid-base balance, lactate concentration, and rating of perceived exertion (RPE) were analyzed. After warm-up with ARDSv, PETCO2 was 45.0 ± 3.7 vs. 41.6 ± 2.5 (mm Hg) (p < 0.001). Body temperature was 0.6 (°C) higher after this form of warm-up (p < 0.05), bicarbonate concentration increased by 1.8 (mmol⋅L–1) (p < 0.01). As a result, work performed was 2.9% greater (p < 0.01) compared to the control condition. Respiratory muscle strength did not decreased. Warming up with added respiratory dead space volume mask prior to cycling SIE produces an ergogenic effect by increasing body temperature and buffering capacity.
... In 2007, an approach consisting in exercising while performing short bouts of end-expiratory breath holding (EEBH) (the so-called voluntary hypoventilation at low lung volume, VHL) emerged in the scientific literature (Woorons et al. 2007). Since then, the acute effects of the VHL technique have been widely investigated. ...
... Since then, the acute effects of the VHL technique have been widely investigated. The studies that dealt with this topic have reported larger levels of carbon dioxide partial pressures (Woorons et al. 2007(Woorons et al. , 2011, lower blood, muscle and cerebral oxygenation (Kume et al. 2016;Woorons et al. 2007Woorons et al. , 2010Woorons et al. , 2014Woorons et al. , 2017Woorons et al. , 2019a and greater stimulation of the anaerobic glycolysis (Kume et al. 2016;Woorons et al. 2010Woorons et al. , 2014 compared with the same exercise performed with unrestricted breathing. Changes at the cardiac level have also been found during VHL exercise (Woorons et al. 2011. ...
... Since then, the acute effects of the VHL technique have been widely investigated. The studies that dealt with this topic have reported larger levels of carbon dioxide partial pressures (Woorons et al. 2007(Woorons et al. , 2011, lower blood, muscle and cerebral oxygenation (Kume et al. 2016;Woorons et al. 2007Woorons et al. , 2010Woorons et al. , 2014Woorons et al. , 2017Woorons et al. , 2019a and greater stimulation of the anaerobic glycolysis (Kume et al. 2016;Woorons et al. 2010Woorons et al. , 2014 compared with the same exercise performed with unrestricted breathing. Changes at the cardiac level have also been found during VHL exercise (Woorons et al. 2011. ...
Purpose: The goal of this study was to assess the effects of repeated running bouts with end-expiratory breath holding (EEBH) up to the breaking point on muscle oxygenation.
Methods: Eight male runners participated in three randomized sessions each including two exercises on a motorized treadmill. The first exercise consisted in performing 10-12 running bouts with EEBH of maximum duration either (separate sessions) at 60% (active recovery), 80% (passive recovery) or 100% (passive recovery) of the maximal aerobic velocity (MAV). Each repetition started at the onset of EEBH and ended at its release. In the second exercise of the session, subjects replicated the same procedure but with normal breathing (NB). Arterial oxygen saturation (SpO2), heart rate (HR) and the change in vastus lateralis muscle deoxy-haemoglobin/myoglobin (Δ[HHb/Mb]) and total haemoglobin/myoglobin (Δ[THb/Mb]) were continuously monitored throughout exercises.
Results: On average, the EEBHs were maintained for 10.1 ± 1.1 s, 13.2 ± 1.8 s and 12.2 ± 1.7 s during exercise at 60%, 80% and 100% of MAV, respectively. In the three exercise intensities, SpO2 (mean nadir values: 76.3 ± 2.5 vs 94.5 ± 2.5 %) and HR were lower with EEBH than with NB at the end of the repetitions whereas the mean Δ[HHb/Mb] (12.6 ± 5.2 vs 7.7 ± 4.4 µm) and Δ[THb/Mb] (- 0.6 ± 2.3 vs 3.8 ± 2.6 µm) were respectively higher and lower with EEBH (p < 0.05).
Conclusion: This study showed that performing repeated bouts of running exercises with EEBH up to the breaking point induced a large and early drop in muscle oxygenation compared with the same exercise with NB. This phenomenon was probably the consequence of the strong arterial oxygen desaturation induced by the maximal EEBHs.
... Blood (approximately 125 μl) was collected from the earlobe in capillary tubes (Roche, Diagnostics GmbH, Mannheim, Germany) before and immediately after the exercise to analyze the following blood gas variables: partial oxygen pressure (pO 2 ), partial carbon dioxide pressure (pCO 2 ), pH, deoxyhemoglobin (HHb), base excess (BE), hematocrit (Hct), bicarbonate concentration (HCO 3 ), and oxygen saturation (SaO2). Ten minutes before the first blood collection, the earlobe was pre-warmed for 5 min to activate blood flow and facilitate absorption of a vasodilator cream (Finalgon; Laboratorios FHER, SA, Barcelona, Spain) [11]. When ...
... Respiratory acidosis is common in some conditions such as chronic obstructive pulmonary disease [17], but this condition can be induced by some techniques such as prolonged expiration, as demonstrated in triathletes [11]. The impaired respiratory mechanics affect the acidbase balance and cause the accumulation of blood CO 2 . ...
... Given the lack of increase in electromyographic activity from SUM QF, we hypothesized that the higher consumption of O 2 was due to the higher activity of respiratory muscles, which might decrease ventilatory efficiency because of the lower number of breaths. This phenomenon was been reported in previous studies that have used prolonged expiration as RMT [11]. ...
This study analyzed the physiological adjustments caused by the use of the Elevation training mask® (2.0), an airflow restriction mask (ARM) during continuous exercise. Eighteen physically active participants (12 men and 6 women) were randomized to two protocols: continuous exercise with mask (CE-ARM) and continuous exercise without mask (CE). Exercise consisted of cycling for 20 minutes at 60% of maximum power. Metabolic variables, lactate, and gas concentration were obtained from arterialized blood samples at pre and post exercise. Continuous expired gases and myoelectric activity of the quadriceps were performed at rest and during the test. We observed no reduction in oxygen saturation in CE-ARM, leading to lower pH, higher carbon dioxide, and greater hematocrit (all p <0.05). The expired gas analysis shows that the CE-ARM condition presented higher oxygen uptake and expired carbon dioxide concentrations (p <0.05). The CE-ARM condition also presented lower ventilatory volume, ventilatory frequency, and expired oxygen pressure (p <0.05). No changes in electromyography activity and lactate concentrations were identified. We conclude that using ARM does not induce hypoxia and represents an additional challenge for the control of acid-base balance, and we suggest the use of ARM as being suitable for respiratory muscle training.
... It is also noticeable that in this study, like in almost all RSH studies, the repeated-sprint performance enhancement was larger than in RSN. Over the last 10 years, it has repeatedly and clearly been shown that exercising with VHL could lead to severe hypoxemia ( Woorons et al. 2007Woorons et al. , 2008Woorons et al. , 2011Woorons et al. , 2014) and consequently to muscle tissue deoxygenation ( Woorons et al. 2010) and could, therefore, represent a valuable and practical way to train under simulated hypoxic conditions. Until recently, VHL had always been performed at submaximal exercise intensities (65-80% ...
... . V O 2max ). In addition to the hypoxemic effect, higher carbon dioxide concentrations (i.e., hypercapnic effect), lower level of pH and increased lactate concentration have consistently been reported when exercising with VHL at moderate intensity, compared with the same exercise with normal breathing (NB) ( Woorons et al. 2007Woorons et al. , 2010Woorons et al. , 2011Woorons et al. , 2014). Thus, the main feature of this type of exercise is to provoke a combined lactic and respiratory acidosis as a result of both the hypoxic and hypercapnic effects. ...
... The first and unexpected result of the present study was that PPO and MPO were not different between the two exercise conditions throughout the whole RSE. Yet we postulated a greater decrement in performance in RSH-VHL due to the combined respiratory and metabolic acidosis that was consistently reported during exercise with VHL ( Woorons et al. 2007Woorons et al. , 2010Woorons et al. , 2014). Unlike our hypothesis, the percentage decrement score was similar in both exercise conditions at S1 and was surprisingly lower in RSH-VHL at S2. Noticeably, during RSE performed in moderate normobaric hypoxia (i.e., below 3000 m or inspired fraction of oxygen > 14.5%), fatigue development was not greater than in normoxic conditions ( Girard et al. 2017). ...
Purpose: This study investigated the effects of repeated-sprint (RS) training in hypoxia induced by voluntary hypoventilation at low lung volume (RSH-VHL) on physiological adaptations, RS ability (RSA) and anaerobic performance.
Methods: Over a three-week period, eighteen well-trained cyclists completed six RS sessions in cycling either with RSH-VHL or with normal conditions (RSN). Before (Pre) and after (Post) the training period, the subjects performed an RSA test (10x6-s all-out cycling sprints) during which oxygen uptake (V ̇O_2) and the change in both muscle deoxyhaemoglobin (Δ[HHb]) and total haemoglobin (Δ[THb]) were measured. A 30-s Wingate test was also performed and maximal blood lactate concentration ([La]max) was assessed.
Results: At Post compared to Pre, the mean power output during both the RSA and the Wingate tests was improved in RSH-VHL (846±98 vs 911±117W and 723±112 vs 768±123W, p<0.05) but not in RSN (834±52 vs 852 ± 69W, p=0.2; 710±63 vs 713±72W, p=0.68). The average V ̇O_2 recorded during the RSA test was significantly higher in RSH-VHL at Post but did not change in RSN. No change occurred for Δ[THb] whereas Δ[HHb] increased to the same extent in both groups. [Lamax] after the Wingate test was higher in RSH-VHL at Post (13.9±2.8 vs 16.1±3.2 mmol.L-1, p<0.01) and tended to decrease in RSN (p=0.1).
Conclusions: This study showed that RSH-VHL could bring benefits to both RSA and anaerobic performance through increases in oxygen delivery and glycolytic contribution. On the other hand, no additional effect was observed for the indices of muscle blood volume and O2 extraction.
... It is noteworthy that 2 recent repeatedsprint studies have reported that when the hypoxic conditions were created through voluntary hypoventilation at low lung volume (VHL), the improvement in RSA performance was larger than in normoxia [16,31]. Since 2007, it has clearly been demonstrated that VHL could induce severe arterial oxygen desaturation [37][38][39][40] leading to muscle deoxygenation [36,40]. In these conditions, the hypoxic state has been shown to be similar to what is observed at an altitude of about 2400 m [35]. ...
... The minimum average level of SpO 2 recorded during the repeated-shuttle sprints with VHL (i. e., 83.9 %, ▶ Fig. 4) confirms what has been reported since 2007, that is this breathing technique induces large arterial desaturation leading to severe hypoxemia [36,37,39]. This minimum level, as well as the average mean SpO 2 reached during RSH-VHL, are in line with findings of recent repeated-sprint studies with VHL conducted in swimming [31], cycling [40] and running [16]. ...
... This makes this technique a good substitute for performing RSH without going to altitude or using devices to create hypoxia. VHL-induced fast and severe hypoxemia is made possible through both a wider alveolar-to-arterial O 2 partial pressure difference as a consequence of a greater ventilationto-perfusion ratio inequality, and a right shift of the O 2 dissociation curve, under the effect of hypercapnia-induced acidosis [39]. This phenomenon is a specific response to breath holding at low lung volume, and is different from what can occur in acute hypoxia which rather leads to hypocapnia and in which the alveolar-to-arterial O 2 partial pressure difference is mainly induced by diffusion limitation rather than a greater ventilation-to-perfusion inequality [30]. ...
Ten highly-trained Jiu-Jitsu fighters performed two repeated-sprint sessions, each including 2 sets of 8 x ~6 s back-and-forth running sprints on a tatami. One session was carried out with normal breathing (RSN) and the other with voluntary hypoventilation at low lung volume (RSH-VHL). Prefrontal and vastus lateralis muscle oxyhaemoglobin ([O2Hb]) and deoxyhaemoglobin ([HHb]) were monitored by near-infrared spectroscopy. Arterial oxygen saturation (SpO2), heart rate (HR), gas exchange and maximal blood lactate concentration ([La]max) were also assessed. SpO2 was significantly lower in RSH-VHL than in RSN whereas there was no difference in HR. Muscle oxygenation was not different between conditions during the entire exercise. On the other hand, in RSH-VHL, cerebral oxygenation was significantly lower than in RSN (-6.1±5.4 vs -1.5±6.6 µa). Oxygen uptake was also higher during the recovery periods whereas [La]max tended to be lower in RSH-VHL. The time of the sprints was not different between conditions. This study shows that repeated shuttle-run sprints with VHL has a limited impact on muscle deoxygenation but induces a greater fall in cerebral oxygenation compared with normal breathing conditions. Despite this phenomenon, performance is not impaired, probably because of a higher oxygen uptake during the recovery periods following sprints.
... Woorons et al. [17] found that IBH exercise causes activation of the anaerobic metabolism that leads to increased lactate production. The mechanism of action for the neutralization of lactic made from NaHCO 3 plasma results in the production of the lactate solution and the release of CO 2 which in turn incorporates the CO 2 transported in the blood. ...
... The arterial oxygen saturation following NB was within normal limits while lower levels occurred after BH and IBH (Fig. 2). Woorons et al. [17] reported that voluntary hypoventilation can cause severe hypoxemia due to the prolonged effort of hypoventilation at submaximal intensity. This happens because of the changes in the frequency and the depth of the breathing affecting the CO 2 and O 2 levels in the arterial blood and performance [18]. ...
... Athletes who train with IBH maintain longer hypoxic ability to exercise, displaying a tolerance to hypoxia [19] than athletes who do not use it enough [20]. Woorons et al. [17] observed that the exercise with infrequently breathing displays similar adjustments to those exhibited by athletes who train at altitude, such as increased activity of respiratory muscles and improve aerobic and anaerobic capacity. ...
Purpose: The purpose of the present study was to examine the effect of three breathing techniques [normal breath (NB), breath holding (BH) and intermittent breath holding (IBH)] on finswimmers’ heart rate (HR), arterial oxygen saturation (SpO2) and maximum inspiratory pressure (PImax).
Methods: Ten young finswimmers (15.8 ± 0.5 years) performed 8 × 25 m freestyle leg kick trials under the three different breathing occasions (NB, BH and IBH). HR, SpO2 and PImax were recorded immediately after the end of each test.
Results: The results showed lower SpO2 values immediately after the end of IBH technique in correlation with the other breathing techniques (IBH: 88 ± 0.9%; BH: 93.3 ± 0.7%; NB: 98.3 ± 0.3%; p < 0.001). Additionally, HR was higher after IBH compared to the other breathing techniques (IBH: 177 ± 4.2 bpm−1; BH: 165.7 ± 7.9 bpm−1; NB: 158.3 ± 2.2 bpm−1, p < 0.001) and PImax was also higher after the IBH compared to the other two techniques (IBH: 168.3 ± 5.3 cmH2O; BH: 166 ± 11 cmH2O; NB: 161.7 ± 11.4 cmH2O; p < 0.05).
Conclusion: The data from the present study support that BH and even more so IBH training acutely increase the inspiratory muscles strength. This is an important training tool to improve the inspiratory muscle performance in athletes.
... It is also noticeable that in this study, like in almost all RSH studies, the repeated-sprint performance enhancement was larger than in RSN. Over the last 10 years, it has repeatedly and clearly been shown that exercising with VHL could lead to severe hypoxemia (Woorons et al. 2007(Woorons et al. , 2008(Woorons et al. , 2011(Woorons et al. , 2014 and consequently to muscle tissue deoxygenation (Woorons et al. 2010) and could, therefore, represent a valuable and practical way to train under simulated hypoxic conditions. Until recently, VHL had always been performed at submaximal exercise intensities (65-80% . ...
... V O 2max ). In addition to the hypoxemic effect, higher carbon dioxide concentrations (i.e., hypercapnic effect), lower level of pH and increased lactate concentration have consistently been reported when exercising with VHL at moderate intensity, compared with the same exercise with normal breathing (NB) (Woorons et al. 2007(Woorons et al. , 2010(Woorons et al. , 2011(Woorons et al. , 2014. Thus, the main feature of this type of exercise is to provoke a combined lactic and respiratory acidosis as a result of both the hypoxic and hypercapnic effects. ...
... The first and unexpected result of the present study was that PPO and MPO were not different between the two exercise conditions throughout the whole RSE. Yet we postulated a greater decrement in performance in RSH-VHL due to the combined respiratory and metabolic acidosis that was consistently reported during exercise with VHL (Woorons et al. 2007(Woorons et al. , 2010(Woorons et al. , 2014. Unlike our hypothesis, the percentage decrement score was similar in both exercise conditions at S1 and was surprisingly lower in RSH-VHL at S2. Noticeably, during RSE performed in moderate normobaric hypoxia (i.e., below 3000 m or inspired fraction of oxygen > 14.5%), fatigue development was not greater than in normoxic conditions (Girard et al. 2017). ...
Purpose:
This study aimed to investigate the acute responses to repeated-sprint exercise (RSE) in hypoxia induced by voluntary hypoventilation at low lung volume (VHL).
Methods:
Nine well-trained subjects performed two sets of eight 6-s sprints on a cycle ergometer followed by 24 s of inactive recovery. RSE was randomly carried out either with normal breathing (RSN) or with VHL (RSH-VHL). Peak (PPO) and mean power output (MPO) of each sprint were measured. Arterial oxygen saturation, heart rate (HR), gas exchange and muscle concentrations of oxy-([O2Hb]) and deoxyhaemoglobin/myoglobin ([HHb]) were continuously recorded throughout exercise. Blood lactate concentration ([La]) was measured at the end of the first (S1) and second set (S2).
Results:
There was no difference in PPO and MPO between conditions in all sprints. Arterial oxygen saturation (87.7 ± 3.6 vs 96.9 ± 1.8% at the last sprint) and HR were lower in RSH-VHL than in RSN during most part of exercise. The changes in [O2Hb] and [HHb] were greater in RSH-VHL at S2. Oxygen uptake was significantly higher in RSH-VHL than in RSN during the recovery periods following sprints at S2 (3.02 ± 0.4 vs 2.67 ± 0.5 L min(-1) on average) whereas [La] was lower in RSH-VHL at the end of exercise (10.3 ± 2.9 vs 13.8 ± 3.5 mmol.L(-1); p < 0.01).
Conclusions:
This study shows that performing RSE with VHL led to larger arterial and muscle deoxygenation than with normal breathing while maintaining similar power output. This kind of exercise may be worth using for performing repeated sprint training in hypoxia.
... An additional reason could be that in RB conditions, swimmers held the air in their lungs delaying expiration for several arm-strokes before they took the next breath. A fast expiration to the level of the functional residual capacity or to the residual volume is required to increase the alveolar-arterial pressure difference of oxygen (P A-a O 2 ) in the lungs and provoke a greater desaturation of haemoglobin during submaximal exercise in the land (Woorons et al., 2007;Yamamoto, Mutoh, Kobayashi, & Miyashita, 1987). ...
... Expiration at the functional residual volume and RB has been shown to induce hypoxemia during submaximal cycling at intensity 65-70% of VO 2 max (Woorons et al., 2007). Considering that the levels of hypoxemia have been defined as severe (oxygen saturation (SpO 2 ) below 88%), moderate (SpO 2 between 88% and 93%) and mild (SpO 2 between 93% and 95%) (Dempsey & Wagner, 1999), a severe hypoxemia was observed during interval swimming at intensity 95% of the swimmers best 400-m speed under hypoventilation along with RB (Woorons, Gamelin, Lamberto, Pichon, & Richalet, 2014). ...
... preliminary testing performance data, the time needed for covering the 75 m was expected to be about 50-60 s and 18-20 s for the subsequent 25 m. This procedure was selected to simulate the 45 s hypoventilation followed by 15 s of N during cycling and running used in previous studies (Woorons et al., 2007(Woorons et al., , 2008. With this experimental protocol, the SpO 2 response and all other variables could be examined as in a continuous 400-m distance trial (Figure 1). ...
The purpose of this study was to examine the metabolic responses during submaximal swimming with self-selected normal breathing (N) and prolonged expiration along with reduced frequency breathing (RB). Ten male swimmers (age: 23.1 ± 2.2 years; VO2max: 47.3 ± 7.2 ml · kg(-1) · min(-1)) performed 75-, 100-, 175-, 200-, 275-, 300-, 375- and 400-m trials with N and RB at intensity corresponding to 90% of the critical speed. In RB condition, all trials longer than 75 m were interspersed with 25 m of self-selected N in regular intervals. In RB, oxygen saturation during recovery was decreased compared to starting values after 75, 100, 175, 275 and 375 m (78-91%, P < 0.05), while it remained unchanged after all trials in N condition (98 ± 2%, P > 0.05). Lactate concentration was higher in RB than in N after 400 m (4.3 ± 1.5 vs. 3.3 ± 1.7 mmol · l(-1), P < 0.05). During recovery after the 375-m trial, partial pressure of carbon dioxide was increased and pH was decreased in RB compared to N condition. Prolonged expiration along with RB provokes severe hypoxemia during the recovery period after swimming, which is restored with self-selected N during submaximal swimming.
... Pontevedra, 2-4 de junio del 2016 en la literatura científica en comparación con la apnea clásica denominada de alto volumen pulmonar que se realiza con almacenamiento de aire (Woorons et al., 2007;Woorons et al., 2013). Algunos estudios sugieren que entrenar en condiciones de bajo volumen pulmonar, es decir, cerca de la capacidad funcional residual puede desembocar en una mayor hipoxemia debida a una menor presión parcial de oxígeno alveolar y a una mayor hetereogeneidad en el ratio de perfusión ventilación (Woorons et al., 2007;Woorons et al., 2013). ...
... Pontevedra, 2-4 de junio del 2016 en la literatura científica en comparación con la apnea clásica denominada de alto volumen pulmonar que se realiza con almacenamiento de aire (Woorons et al., 2007;Woorons et al., 2013). Algunos estudios sugieren que entrenar en condiciones de bajo volumen pulmonar, es decir, cerca de la capacidad funcional residual puede desembocar en una mayor hipoxemia debida a una menor presión parcial de oxígeno alveolar y a una mayor hetereogeneidad en el ratio de perfusión ventilación (Woorons et al., 2007;Woorons et al., 2013). ...
... Algunos deportistas que requieren de sostener la respiración bajo el agua como la natación, la natación sincronizada o el hockey subacuático, también han mostrado respuesta de buceo como bradicardia y desaturación de oxígeno arterial (Guimard et al., 2014;Lemaitre et al., 2007;Rodríguez-Zamora et al., 2012). La sugerencia de una mejora del metabolismo anaeróbico durante el entrenamiento en apnea ha llevado a plantearse como una alternativa al entrenamiento hipobárico o hipóxico para mejorar el rendimiento aeróbico o anaeróbico de atletas (Lemaitre, Joulia & Chollet, 2010;Woorons et al., 2007). Se requieren mas estudios de la respuesta fisiológica del entrenamiento en apnea sobre el rendimiento deportivo y sobre diferentes aspectos relacionados con la salud para dar soporte a esta teoría. ...
Introduction: Hypopressive Exercise (HE) which is performed in stretching poses with voluntary expiratory breath-hold may evoke the physiological consequences of the diving response. The purpose of this study was to investigate the cardiovascular response of HE in a group of healthy subjects trained in this modality.
Material y Métodos: 15 healthy and physically active subjects [age 41.93(7.68) years; body mass index: 25.24 (4.19) kg/m2] with a minimun six month previous experience training HE completed two experimental trials. The first consisted in a 20-minute training of five HE repeated three times combined with voluntary exhale breath-hold (EHA). After one week, the same procedure was repeated but without breath-holding (EHN). Heart Rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and arterial oxygen saturation (Sp02) were measured during three phases of the trials; rest, training and inmediate recover after the first, fifth and fifteenth minute of the first ventilation. During each repetición of HE were recored HR and Sa02. Was assesed with pulse oximeter and sphygmomanometer.
Results: The multivariate analysis of variance (MANOVA) showed significant differences between both trials for HR, SBP, DBP and Sp02 (p<.01). HR and Sp02 showed significant differences between the different phases of the training session (p<.01). All baseline values recovered completly within fifteen minutes from the first ventilation.
Conclusions: HE when is performed under conditions of hypoventilation by healthy subjects with experience training HE induces cardiovascular changes observed in the diving response like bradycardia, arterial oxygen desaturation and peripheral vasoconstriction
Introducción: El Ejercicio Hipopresivo (EH) se realiza en posturas de auto-estiramiento con apneas espiratorias voluntarias pudiendo inducir las consecuencias fisiológicas de la respuesta del buceo. El objetivo de este estudio fue estudiar la respuesta cardiovascular del EH en un grupo de sujetos con experiencia previa en dicha modalidad. Material y Métodos: Quince sujetos físicamente activos [edad 41.93(±7.68) años; Índice de Masa Corporal: 25.24 (4.19) kg/m 2 ] con experiencia previa entrenando EH completaron dos ensayos experimentales: el primero consistente en un entrenamiento de 20 minutos de cinco EH repetidos tres veces con apnea voluntaria (EHA) y una semana después se repitió el mismo entrenamiento sin incluir la apnea (EHN). Se han valorado la frecuencia cardíaca (FC), la presión arterial sistólica (PAS), presión arterial diastólica (PAD) y la saturación de oxígeno arterial (Sp0 2) en tres fases de los ensayos: reposo, entrenamiento y recuperación inmediata tras la última ventilación al primero, quinto y decimoquinto minuto. Durante cada repetición de EH en la fase de entrenamiento se registró la FC y Sp0 2 para ambos ensayos. Se valoró con esfingomanómetro y pulsioxímetro digital. Resultados: El análisis de la varianza multifactorial (MANOVA) señaló diferencias significativas entre los dos ensayos para la FC, Sa0 2 , TAD y TAS (p<.01). La FC y Sa0 2 mostraron diferencias significativas entre las diferentes fases de la sesión de entrenamiento (p<.01). Todos los valores basales se recuperaron completamente a los quince minutos de la primera ventilación. Conclusiones: El EH cuando se realiza bajo condiciones de apnea espiratoria por sujetos sanos entrenados en dicha modalidad induce cambios cardiovasculares propios de la respuesta de buceo como bradicardia, desaturación de oxígeno arterial y vasoconstricción periférica.
... After a 5-min rest on the cycle ergometer, subjects performed a 3-min warm-up exercise at an exercise intensity corresponding to 45 % of V O 2peak with NB, followed by a 5-min exercise at 65 % V O 2peak under conditions of VH or NB. We employed the modified VH technique reported by Woorons et al. (2007). Namely, when the exercise was performed under VH conditions, the 5-min exercise was divided into five periods of 1 min each that included 10 s of NB followed by 50 s of VH. ...
... These results are consistent with those from a previous study (Woorons et al. 2010) and our preliminary observations. Woorons et al. (2007Woorons et al. ( , 2010Woorons et al. ( , 2011 have indicated that exercise under VH conditions is different from exercise under hypoxic conditions because VH also induces hypercapnia. The hypercapnic response leads to respiratory acidosis and consequently a right shift of the oxygen dissociation curve. ...
... The hypercapnic response leads to respiratory acidosis and consequently a right shift of the oxygen dissociation curve. Thus, VH-induced hypercapnia more facilitates arterial (Woorons et al. 2007). We presume that similar hypercapnic effects occurred in the VH condition in this study, although arterial and end-tidal carbon dioxide pressure measurements were not taken. ...
It has been reported that exercise under hypoxic conditions induces reduced muscle oxygenation, which could be related to enhanced activity on electromyography (EMG). Although it has been demonstrated that exercise under conditions of voluntary hypoventilation (VH) evokes muscle deoxygenation, it is unclear whether VH during exercise impacts EMG. Seven men performed bicycle exercise for 5 min at 65 % of peak oxygen uptake with normal breathing (NB) and VH. Muscle oxygenation; concentration changes in oxyhemoglobin (Oxy-Hb), deoxyhemoglobin (Deoxy-Hb) and total hemoglobin (Total-Hb); and surface EMG in the vastus lateralis muscle were simultaneously measured. In the VH condition, Oxy-Hb was significantly lower and Deoxy-Hb was significantly higher compared to those in the NB condition (P < 0.05 for both), whereas there was no significant difference in Total-Hb between the two conditions. We observed significantly higher values (P < 0.05) on integrated EMG during exercise under VH conditions compared to those under NB conditions. This study suggests that VH during exercise augments EMG activity.
... In two recent studies, it has been suggested that training with voluntary hypoventilation (VH) could be an interesting method for athletes who want to benefit from hypoxia without going to altitude or using expensive devices that simulate hypoxic environment (Woorons et al. 2007Woorons et al. , 2008). According to these studies, the key point when using VH is to perform this technique at low pulmonary volumes, near functional residual capacity (FRC) or residual volume (RV). ...
... According to these studies, the key point when using VH is to perform this technique at low pulmonary volumes, near functional residual capacity (FRC) or residual volume (RV). In those conditions, rather than with a simple VH, there is a decrease in O 2 alveolar stores and a greater inequality in the ventilation–perfusion ratio leading to a widened alveolar–arterial difference for O 2 (Woorons et al. 2007). Thus, a significant arterial desaturation occurs, unlike a VH performed at high pulmonary volumes (Yamamoto et al. 1987). ...
... Thus, a significant arterial desaturation occurs, unlike a VH performed at high pulmonary volumes (Yamamoto et al. 1987). In addition to severe hypoxemia (arterial oxygen saturation [SaO 2 ] = 87%), submaximal exercise with VH also induces an increased arterial carbon dioxide pressure (PaCO 2 ) leading to respiratory acidosis (Woorons et al. 2007). After a 4-week training with VH carried out at FRC, both pH and bicarbonate concentration were found increased at a high submaximal intensity but not at maximal exercise (Woorons et al. 2008 ). ...
Eight men performed three series of 5-min exercise on a cycle ergometer at 65% of normoxic maximal O 2 consumption in four conditions: (1) voluntary hypo-ventilation (VH) in normoxia (VH 0.21), (2) VH in hyper-oxia (inducing hypercapnia) (inspired oxygen fraction [F I O 2 ] = 0.29; VH 0.29), (3) normal breathing (NB) in hypoxia (F I O 2 = 0.157; NB 0.157), (4) NB in normoxia (NB 0.21). Using near-infrared spectroscopy, changes in concentration of oxy-(D[O 2 Hb]) and deoxyhemoglobin (D[HHb]) were measured in the vastus lateralis muscle. D[O 2 Hb -HHb] and D[O 2 Hb ? HHb] were calculated and used as oxygenation index and change in regional blood volume, respectively. Earlobe blood samples were taken throughout the exercise. Both VH 0.21 and NB 0.157 induced a severe and similar hypoxemia (arterial oxygen saturation [SaO 2 ] \ 88%) whereas SaO 2 remained above 94% and was not different between VH 0.29 and NB 0.21 . Arterialized O 2 and CO 2 pressures as well as P50 were higher and pH lower in VH 0.21 than in NB 0.157 , and in VH 0.29 than in NB 0.21 . D[O 2 Hb] and D[O 2 Hb -HHb] were lower and D[HHb] higher at the end of each series in both VH 0.21 and NB 0.157 than in NB 0.21 and VH 0.29 . There was no difference in D[O 2 Hb ? HHb] between testing conditions. [La] in VH 0.21 was greater than both in NB 0.21 and VH 0.29 but not different from NB 0.157 . This study demonstrated that exercise with VH induced a lower tissue oxygenation and a higher [La] than exercise with NB. This was caused by a severe arterial O 2 desaturation induced by both hypoxic and hypercapnic effects.
... In the mid 2000s, a new approach of exercising with voluntary hypoventilation (VH) was proposed by our laboratory. We postulated that when VH is performed in the classical way, which is at high pulmonary volume like in swimming, the alveolar O 2 stores are enhanced and gas exchanges are facilitated which therefore prevents obtaining a hypoxemic effect (Woorons et al., 2007). On the contrary, we hypothesized that VH at low pulmonary volume, that is at or below functional residual capacity (FRC), should lower the alveolar O 2 partial pressure (P A O 2 ) and induce a greater heterogeneity of the ventilation to perfusion ratio (V/Q ), thus increasing the alveolar to arterial difference for O 2 (D(A-a)O 2 ). ...
... On the contrary, we hypothesized that VH at low pulmonary volume, that is at or below functional residual capacity (FRC), should lower the alveolar O 2 partial pressure (P A O 2 ) and induce a greater heterogeneity of the ventilation to perfusion ratio (V/Q ), thus increasing the alveolar to arterial difference for O 2 (D(A-a)O 2 ). This hypothesis was verified in cycling and running where the arterial O 2 saturation (SaO 2 ) fell down to 87% on average (Woorons et al., 2007(Woorons et al., , 2008(Woorons et al., , 2010(Woorons et al., , 2011. The severe hypoxemia induced by VH at FRC also led to a greater muscle deoxygenation and therefore likely to tissue hypoxia (Woorons et al., 2010). ...
... It has been shown that when VH down to residual volume is carried out during a cycling exercise, the resulting severe hypoxemia is caused by three factors: a decrease in P A O 2 , a right shift of the oxygen dissociation curve (ODC) and a greater D(A-a)O 2 (Woorons et al., 2007). In the present study, the lower P ET O 2 in VH low than in NB from the beginning to the end of exercise and the significant relationship between P ET O 2 and SpO 2 in VH low confirm the role of P A O 2 . ...
... In two recent studies, it has been suggested that training with voluntary hypoventilation (VH) could be an interesting method for athletes who want to benefit from hypoxia without going to altitude or using expensive devices that simulate hypoxic environment (Woorons et al. 2007Woorons et al. , 2008). According to these studies, the key point when using VH is to perform this technique at low pulmonary volumes, near functional residual capacity (FRC) or residual volume (RV). ...
... According to these studies, the key point when using VH is to perform this technique at low pulmonary volumes, near functional residual capacity (FRC) or residual volume (RV). In those conditions, rather than with a simple VH, there is a decrease in O 2 alveolar stores and a greater inequality in the ventilation–perfusion ratio leading to a widened alveolar–arterial difference for O 2 (Woorons et al. 2007). Thus, a significant arterial desaturation occurs, unlike a VH performed at high pulmonary volumes (Yamamoto et al. 1987). ...
... Thus, a significant arterial desaturation occurs, unlike a VH performed at high pulmonary volumes (Yamamoto et al. 1987). In addition to severe hypoxemia (arterial oxygen saturation[SaO 2 ]= 87%), submaximal exercise with VH also induces an increased arterial carbon dioxide pressure (PaCO 2 ) leading to respiratory acidosis (Woorons et al. 2007). After a 4-week training with VHcarried out at FRC, both pH and bicarbonate concentration were found increased at a high submaximal intensity but not at maximal exercise (Woorons et al. 2008). ...
Eight men performed three series of 5-min exercise on a cycle ergometer at 65% of normoxic maximal O(2) consumption in four conditions: (1) voluntary hypoventilation (VH) in normoxia (VH(0.21)), (2) VH in hyperoxia (inducing hypercapnia) (inspired oxygen fraction [F(I)O(2)] = 0.29; VH(0.29)), (3) normal breathing (NB) in hypoxia (F(I)O(2) = 0.157; NB(0.157)), (4) NB in normoxia (NB(0.21)). Using near-infrared spectroscopy, changes in concentration of oxy-(Delta[O(2)Hb]) and deoxyhemoglobin (Delta[HHb]) were measured in the vastus lateralis muscle. Delta[O(2)Hb - HHb] and Delta[O(2)Hb + HHb] were calculated and used as oxygenation index and change in regional blood volume, respectively. Earlobe blood samples were taken throughout the exercise. Both VH(0.21) and NB(0.157) induced a severe and similar hypoxemia (arterial oxygen saturation [SaO(2)] < 88%) whereas SaO(2) remained above 94% and was not different between VH(0.29) and NB(0.21). Arterialized O(2) and CO(2) pressures as well as P50 were higher and pH lower in VH(0.21) than in NB(0.157), and in VH(0.29) than in NB(0.21). Delta[O(2)Hb] and Delta[O(2)Hb - HHb] were lower and Delta[HHb] higher at the end of each series in both VH(0.21) and NB(0.157) than in NB(0.21) and VH(0.29). There was no difference in Delta[O(2)Hb + HHb] between testing conditions. [La] in VH(0.21) was greater than both in NB(0.21) and VH(0.29) but not different from NB(0.157). This study demonstrated that exercise with VH induced a lower tissue oxygenation and a higher [La] than exercise with NB. This was caused by a severe arterial O(2) desaturation induced by both hypoxic and hypercapnic effects.
... This so-called diving response is characterized by bradycardia, peripheral vasoconstriction, and increased blood pressure, reduced cardiac output and blood flow, and increased sympathetic activity (Sterba and Lundgren, 1988;Foster and Sheel, 2005). Also, apnea leads to hypercapnia (Qvist et al., 1985), which has many consequences particularly on tissue oxygenation (Woorons et al., 2010), lactatemia (Graham et al., 1980), and probably discomfort (Woorons et al., 2007). The diving response (and the bradycardic phenomenon) is somehow in contradiction with exercise, which implies an increase in heart rate (Alboni et al., 2011), and this is why it is difficult to identify physiological patterns for apnea in the context of exercise performance and particularly in swimming. ...
... A previous study had reported higher RPE in swimmers in apnea than in normal breathing conditions when swimming at a 400 m race velocity (Guimard et al., 2018). The reason for this is the apnea-induced hypercapnia associated with prolonged exercise duration (Woorons et al., 2007), which causes discomfort, and it could also be the reason for swimmers perceiving a higher level of effort during longer underwater swimming. Lack of differences in RPE between the conditions 2 and 3 (where swimmers performed maximum underwater distances) could be explained by the lack of differences in the total underwater distances between conditions ( Table 2), despite the tendency for swimmers to perform one more kick in condition 3. Swimmers tried to maximally extend the underwater swimming in condition 3, but their underwater kicking was probably not efficient enough to maintain the distance per kick at the end of underwater sections (Zamparo et al., 2012). ...
Despite changes in the underwater sections of swimming races affecting overall performance, there is no information about the effects of the apnea-induced changes on the physiological state of competitive swimmers. The aim of the present research was to examine the effect of changes in the underwater race sections on the physiological [blood lactate concentration, heart rate, and rating of perceived exertion (RPE)] and biomechanical (underwater time, distance, and velocity) parameters of competitive swimmers. Twelve youth competitive swimmers belonging to the national team (706 ± 28.9 FINA points) performed 2 × 75 m efforts under three different conditions, while maintaining a 200 m race pace: (1) free underwater sections, (2) kick number of condition 1 plus two kicks, and (3) maximum distance underwater. Overall performance was maintained, and underwater section durations increased from condition 1 to 3 as expected according to the experimental design. Heart rate and blood lactate concentration values did not show differences between conditions, but the RPE values were significantly greater (F2, 36 = 18.00, p = 0.001, η²: 0.50) for the constrained (conditions 2 and 3) vs. the free underwater condition. Underwater parameters were modified within the 75 m efforts (lap 1 to lap 3), but the magnitude of changes did not depend on the experimental condition (all lap × condition effects p > 0.05). Controlled increases of underwater sections in trained swimmers can led to optimizing performance in these race segments despite small increases of perceived discomfort.
... In turn, other studies inform that the energy cost of respiratory muscle work was higher when breathing with ARDS V [34], with a training mask [8], and with air enriched with CO 2 [6], which resulted from greater muscle involvement. Similar interpretation was provided by Woorons et al. [40], who used hypoventilation during exercise. Another factor contributing to higher VO 2 in SIE ARDS may be related to the right-shift of the hemoglobin dissociation curve during acidosis, which is in accordance with the Bohr effect [41]. ...
... It can be considered that the outcome of this study was limited by the fact that the participants were not blinded and that the differences in the amount of work performed and the lack of differences in RPE resulted from the placebo effect. Similar observations were earlier reported by Woorons et al. [37,40], who investigated the impact of hypoventilation. A corresponding problem refers to ARDS V , as it is impossible to conduct single-or double-blind trials. ...
Background: The aim of the study was to compare acute physiological, biochemical, and perceptual responses during sprint interval exercise (SIE) with breathing through a device increasing added respiratory dead space volume (ARDSV) and without the device. Methods: The study involved 11 healthy, physically active men (mean maximal oxygen uptake: 52.6 ± 8.2 mL∙kg1∙min−1). During four visits to a laboratory with a minimum interval of 72 h, they participated in (1) an incremental test on a cycle ergometer; (2) a familiarization session; (3) and (4) cross-over SIE sessions. SIE consisted of 6 × 10-s all-out bouts with 4-min active recovery. During one of the sessions the participants breathed through a 1200-mL ARDSv (SIEARDS). Results: The work performed was significantly higher by 4.4% during SIEARDS, with no differences in the fatigue index. The mean respiratory ventilation was significantly higher by 13.2%, and the mean oxygen uptake was higher by 31.3% during SIEARDS. Respiratory muscle strength did not change after the two SIE sessions. In SIEARDS, the mean pH turned out significantly lower (7.26 vs. 7.29), and the mean HCO3– concentration was higher by 7.6%. Average La− and rating of perceived exertion (RPE) did not differ between the sessions. Conclusions: Using ARDSV during SIE provokes respiratory acidosis, causes stronger acute physiological responses, and does not increase RPE.
... Training with voluntary hypoventilation at low lung volume (VHL) is a method which consists in repeating short bouts of end-expiratory breath holding (EEBH) while exercising [1]. When applied to different exercise modes, this approach acutely provokes an increase in carbon dioxide partial pressures and a decrease in arterial oxygen (O 2 ) partial pressures [2][3][4] leading to blood and muscle deoxygenation [5][6][7]. ...
... Until now, in the studies that investigated the acute effects of VHL exercise, EEBH had been performed over a fixed duration (i. e. 4-6 s) [3,5,6] and a fixed distance [8], or until the subjects felt a strong urge to breathe [21]. In the present study, the participants were required for the first time to perform each exercise bout while maintaining EEBH for as long as possible, that is until the breaking point. ...
Eight well-trained male cyclists participated in two testing sessions each including two sets of 10 cycle exercise bouts at 150% of maximal aerobic power. In the first session, subjects performed the exercise bouts with end-expiratory breath holding (EEBH) of maximal duration. Each exercise bout started at the onset of EEBH and ended at its release (mean duration: 9.6±0.9 s; range: 8.6–11.1 s). At the second testing session, subjects performed the exercise bouts (same duration as in the first session) with normal breathing. Heart rate, left ventricular stroke volume (LVSV), and cardiac output were continuously measured through bio-impedancemetry. Data were analysed for the 4 s preceding and following the end of each exercise bout. LVSV (peak values: 163±33 vs. 124±17 mL, p<0.01) was higher and heart rate lower both in the end phase and in the early recovery of the exercise bouts with EEBH as compared with exercise with normal breathing. Cardiac output was generally not different between exercise conditions. This study showed that performing maximal EEBH during high-intensity exercise led to a large increase in LVSV. This phenomenon is likely explained by greater left ventricular filling as a result of an augmented filling time and decreased right ventricular volume at peak EEBH.
... Les trois étapes de la technique d'hypoventilation à bas volume pulmonaire. (Woorons et al., 2007a). ...
... Tout d'abord, pour obtenir une diminution significative de SpO2 sans être dans un environnement hypoxique, il faut que l'hypoventilation volontaire soit réalisée à bas volume pulmonaire proche de la capacité résiduelle fonctionnelle ou de la réserve ventilatoire (Woorons et al., 2007a;Yamamoto et al., 1987). (Dempsey and Wagner, 1999)). ...
Rugby union is a team sport characterized by high-intensity collisions and running efforts during games which are position-dependent. Accounting for the five different positional groups, the first part of this thesis demonstrated greater high-intensity activity in European cup when compared to the TOP14 rugby union competition with position-dependent variations in the frequency of repeated high-intensity efforts and the relative
distance of high-speed movements in forwards. A decrease in high-intensity movement parameters was observed during the first and second halves of a competitive rugby union match. Indeed, the decrease in high-intensity movements was earlier in forwards and outside backs who peaked in high-intensity accelerations between the last two periods of the game, while backs were able to maintain their high-intensity activity throughout the match. Collectively, the capacity for a player to repeat high-intensity efforts during a rugby union game varied by the level of competition and was influenced by the onset of fatigue. In this context, the second part of this thesis was to conduct a repeated-sprint training in hypoxia. Hypoxia was induced by voluntary hypoventilation at low lung volume. This training protocol has largely improved the repeated-sprint ability performance in highly-trained rugby union players after seven training sessions of hypoventilation, whereas it was unaltered in the control normoxic group. Such training demands in rugby union (characterised by repeated high-intensity efforts in dynamic (running) and static (weightlifting, fighting)) have a specific impact on left ventricular remodelling. The
last part of this thesis, using 2D-speckle-tracking resting echocardiography, demonstrated that LV hypertrophy was greater in forwards when compared to backs and to control group. Systolic function remained unchanged, but diastolic function was altered, mainly in forwards, with an increase in filling pressures and a decrease in left ventricular relaxation. Finally, left ventricular twisting was similar while rugby union players exhibited lower
apical and higher basal rotations velocities compared to controls. Collectively, this CIFRE research program provided new data in activity analysis and training methods that are widely applicable to a range of rugby union programs and data on left ventricular morphology, function and mechanics for the clinician.
... Les trois étapes de la technique d'hypoventilation à bas volume pulmonaire.(Woorons et al., 2007a) 1.2.3.2.Effets physiologiques de l'exercice en hypoventilation L'exercice couplé à une expiration prolongée jusqu'au volume résiduel permet d'obtenir une hypoxémie et une augmentation de la pression artérielle en dioxyde de carbone (PaCO2) (effet hypercapnique)(Woorons et al., 2007b).Tout d'abord, pour obtenir une diminution significati ...
... Les trois étapes de la technique d'hypoventilation à bas volume pulmonaire.(Woorons et al., 2007a) 1.2.3.2.Effets physiologiques de l'exercice en hypoventilation L'exercice couplé à une expiration prolongée jusqu'au volume résiduel permet d'obtenir une hypoxémie et une augmentation de la pression artérielle en dioxyde de carbone (PaCO2) (effet hypercapnique)(Woorons et al., 2007b).Tout d'abord, pour obtenir une diminution significative de SpO2 sans être dans un environnement hypoxique, il faut que l'hypoventilation volontaire soit réalisée à bas volume pulmonaire proche de la capacité résiduelle fonctionnelle ou de la réserve ventilatoire(Woorons et al., 2007a;Yamamoto et al., 1987).Cette technique de blocage respiratoire induit une diminution des réserves alvéolaires en oxygène et conduit à une plus grande inégalité dans le ratio ventilation/perfusion (V/Q) (Morrison et al., 1982) entraînant par conséquent une différence alvéolaire-artérielle en oxygène plus large (PAO2 -PaO2) et une désaturation artérielle en oxygène sévère (Woorons et al., 2007a) (i.e., (SpO2) < 88%, (Dempsey and Wagner, 1999)). Cette modalité d'entraînement est ainsi reconnue comme étant une variante des méthodes d'entraînements hypoxiques Ensuite, l'exercice sous-maximal associé à la VHL induit en complément d'une désaturation artérielle sévère, une augmentation de PaCO2, un plus faible niveau de pH et une augmentation de la lactatémie(Woorons et al., 2007b). ...
Le rugby à XV est un sport collectif qui se caractérise en match par des courses et des collisions de hauteintensité très variables selon les positions. La première partie des travaux, qui s’est centrée sur l’analyse del’activité par centrale d’analyse cinématique, a mis en évidence une activité de haute intensité plus importante enCoupe d’Europe qu’en TOP14 qui varie selon les cinq postes de jeu en termes de répétitions d’efforts et dedistances parcourues à haute intensité notamment chez les avants. De plus, ces activités de haute intensitédiminuent en première et deuxième mi-temps et sont différentes selon les positions. En effet, une diminution plusprécoce est observée chez les avants et les trois-quarts ailes, qui est majorée au niveau des accélérations entre lesdeux dernières périodes d’un match pour les avants démontrant un impact de la fatigue. A l’inverse, les arrièresarrivent globalement à maintenir une intensité élevée. Ainsi, au regard des résultats de la première partie, ladeuxième partie des travaux a consisté en la mise en place d’un entraînement par répétition de sprints en hypoxieinduite par hypoventilation à bas volume pulmonaire. Celui-ci a permis une amélioration significative de lacapacité à répéter des sprints après sept séances d’entraînement par hypoventilation chez les joueurs très entraînés,alors qu’aucun changement n’a été observé dans le groupe normoxie. L’entraînement en rugby à XV se caractérisepar la répétition d’efforts de haute intensité à dominante dynamique (courses) et statique (musculation, phases decombat) qui vont impacter le remodelage du ventricule gauche de manière spécifique. La troisième partie a montré,à partir d’échocardiographies de repos en mode 2D-strain, une hypertrophie physiologique majorée chez les avantscomparativement aux arrières. Cette hypertrophie s’accompagne d’une augmentation des pressions de remplissageet une diminution de la relaxation lors de la diastole, notamment chez les avants. Enfin, malgré une torsionventriculaire inchangée, les rotations et les vitesses de rotation sont plus grandes au niveau basal et plus faibles auniveau apical chez les joueurs de rugby à XV. Ainsi, cette thèse CIFRE apporte de nouvelles données au niveaude l’analyse de l’activité, des méthodes d’entraînement facilement applicables pour l’entraîneur, ainsi que desdonnées plus spécifiques à l’évaluation cardiaque de repos pour le clinicien.
... PaΟ 2 (mmHg) = 102-[0,33 x (Ηιηθία ζε έηε)]. ε έξεπλεο έρεη παξαηεξεζεί πσο ε άπλνηα πνπ ζπλνδεχεηαη απφ ππνμαηκία, πξνθαιεί δηαζηνιή ηεο LV ρσξίο σζηφζν λα ππάξρεη κεηαβνιή ζηε θαξδηαθή παξνρή θαη ηνλ SV (Pingitore et al., 2008) (Woorons et al., 2007;Marabotti, et al., 2009;Woorons et al., 2011). Οη παξαπάλσ κειέηεο πεξηγξάθνπλ ηηο άκεζεο αληαπνθξίζεηο ηεο άζθεζεο κε ΠΑ αιιά δελ είλαη γλσζηφ εάλ κπνξεί ν πεξηνξηζκφο απηφο λα πξνθαιέζεη πξνζαξκνγέο ζηε κνξθνινγία ηνπ κπνθαξδίνπ χζηεξα απφ καθξφρξνλε έθζεζε ζε ππνμία φπσο ζπκβαίλεη ζην πςφκεηξν. ...
... Ο κεραληζκφο ηεο ππεξθαπλίαο απμάλεη ηνλ πλεπκνληθφ αεξηζκφ πεξηζζφηεξν απφ εθείλα ηα επίπεδα πνπ είλαη απαξαίηεηα γηα ηελ επαξθή νμπγφλσζε ηνπ αίκαηνο (Υαηδεθσλζηαληίλνπ, 1993). Ο θνξεζκφο ηνπ αξηεξηαθνχ Ο 2 ζηελ πξψηε κέηξεζε ήηαλ ζηα θπζηνινγηθά επίπεδα θαη γηα ηηο δπν νκάδεο (>96) ελψ ζεκαληηθέο δηαθνξέο εκθαλίζηεθαλ κεηά ηελ πεξίνδν παξέκβαζεο θαη ηε δεχηεξε θνιπκβεηηθή δνθηκαζία (ρήκα 5) κε ηελ νκάδα κε ΠΑ λα εκθαλίδεη ππνμαηκία κεηά απφ ηελ πξνζπάζεηα (89% SpO 2 ) επξήκαηα ηα νπνία ζπκθσλνχλ κε πξνεγνχκελε κειέηε (Woorons et al., 2007). ...
Reduced breathing frequency (RBF) is used by finswimming (FSW) athletes during training and is likely to affect heart function and induce metabolic adaptation that boosts performance. The purpose of this study is to assess the effect of 16 weeks of training with RBF on cardiovascular function parameters and on performance of 28 FSW athletes divided into two groups of equal size. Participants followed the same daily training schedule with self-selected breathing frequency (SBF n=14) or RBF (n=14) at 40% of training distance and intensity corresponding to 70% of their personal best performance. Cardiac parameters related to heart morphology and arterial blood pressure were recorded at rest before and after training. Moreover, blood oxygen saturation (SpO2), and heart rate (HR) were recorded before and after 50 m apnea swimming. Timing at 50m apnea swimming and 400 m of finswimming were used as performance criteria. Intraventricular septum thickness during heart contraction (IVSs) and dilation (IVSd) increased in SBF (5±8 and 9±15%) and decreased in RBF (7±19 and 10±19%) after the training period revealing interaction between the two groups and initial-final measurements (IVSs and IVSd, p<0,05). Prior to training SpO2 dropped equally after 50 m in both groups but after training the reduction was greater (p<0,05) at RBF group (-7,3±3,4%) compared to SBF group (-2,5±1,6%). Performance at 50 and 400 m was improved in both groups (p<0,05) and RBF group was significantly improved at 400 m compared to SBF group (p<0,05). Improved performance and lower SpO2 in RBF group was probably the result of low ventilation and hypoxia tolerance. Furthermore, RBF training conditions could have resulted in increased metabolic adaptation compared to SBF group. RBF improves performance in 400 m but not in 50 m of finswimming. Despite the fact that cardiac morphology was not differentiated significantly between the two groups even after the 16 weeks training period, it showed a tendency for different adaptation in IVSs and IVSd.
... Expiration is considered a passive process during quiet breathing, but with an increased breathing effort, forced expiration can facilitate the activation of (Simpson, 1983). The pressure of intra-abdominal is increased and the diaphragm is moved upwards for forced expiration while the abdominal musculature contracts (Campbell and Green, 1953;Woorons et al, 2007). Therefore, forced expiration can be applied to abdominal curl-up exercise and the other core stabilizing exercise (Cho et al, 2013;Kim and Lee, 2013;Lee et al, 2013). ...
... Particularly, combined task of the cross knee curl-up and forced expiration would be beneficial with increasing abdominal muscle activity while as maintaining of neural spine during core stabilizing exercise. To the best of knowledge, this is the original study to examine the effects of slowly forced expiration (Woorons et al, 2007) on activity of abdominal muscles such as rectus abdominis (RA), external oblique (EO), and transverse abdominis/internal oblique (TrA/IO). These muscles are defined as major expiratory muscles (Neumann, 2002). ...
1) Cross knee curl-up is an ideal variation of abdominal curl up exercise to strengthen abdominal musculature without excessive lumbar flexion which can increase the loads on the disc and ligaments. In addition, slowly forced expiration can facilitate the activation of the abdominal musculature. The purpose of this study was to determine the effects of slowly forced expiration on activity of abdominal muscles, such as rectus abdominis (RA), external oblique (EO), and transverse abdominis/internal oblique (TrA/IO), while cross knee curl-up. Eleven young and healthy subjects (6 males and 5 females) participated. All subjects performed the cross knee curl-up slowly forced expiration and natural breathing. Paired t-test was performed in normalized electromyogram (EMG) muscle activity of the bilateral RA, EO, and TrA/IO to compare the differences between the cross curl-up with slowly forced expiration and natural breathing. Statistical significance was set at .05. There were no significant differences in normalized EMG muscle activity of the bilateral RA, EO, and TrA/IO between the cross curl-up with slowly forced expiration and natural breathing. The finding of this study designates that slowly forced expiration does not induce increasing activity of abdominal muscle in cross knee curl-up; hence, learning step of breathing control might not be necessary to strengthen abdominal muscle in cross knee curl-up.
... To perform this respiratory technique, immediately after each inspiration, the participants were asked to perform a passive expiration and then hold their breath 10 s until the next inspiration. According to previous studies [22], this expiration maneuver reduces SpO 2 . Additionally, exercise with apnea bouts also induces increased arterial carbon dioxide concentration, leading to respiratory acidosis [23]. ...
Introduction: Exercise-induced hypoalgesia is a phenomenon in which exercise bouts induce a reduction in pain sensitivity. Apnea training involves similar characteristics that could potentially induce hypoalgesia. Objectives: The objectives of this study are to explore the effect of apnea training on hypoalgesia; assess the correlation between conditioned pain modulation (CPM) response and apnea-induced hypoalgesia; and examine the association between hypoalgesia with hypoxemia, and heart rate (HR) during apnea. Methods: A randomized controlled trial was conducted comparing a walking protocol employing intermittent apnea compared with normal breathing in healthy volunteers. Hypoalgesia was tested with pressure pain thresholds (PPTs) and CPM. Oxygen saturation (SpO2) and HR were also tested. Results: Relevant but not significant changes were detected in the thumb (MD = 0.678 kg/cm2), and tibialis (MD = 0.718 kg/cm2) in favor of the apnea group. No significant differences were detected in CPM. The apnea group presented lower SpO2, but HR values similar to those of the control group during the intervention. Basal CPM and intrasession hypoxemia significantly correlated with the PPT response. However, HR did not correlate with the PPT response. Conclusions: The current results suggest a trend, though not statistically significant, toward an improvement in the PPT in favor of apnea training compared to normal breathing. Nevertheless, subjects who presented greater basal CPM and lower oxygen saturation during the session presented a greater PPT response, suggesting the possibility of mediators of response. Future investigations should clarify this phenomenon.
... Recently, a new active modality, the so-called voluntary hypoventilation at low lung volume (VHL), has been included in the nomenclature of the LLTH methods (Girard et al., 2017). The VHL technique, which consists of repeating short bouts of exercise (generally 4-6 s) with end-expiratory breath holding (EEBH), has been consistently reported to induce a drop in peripheral arterial oxygen saturation (SpO 2 ) (i.e., down to 86%-88% on average) and in muscle oxygenation as well as higher levels of blood and pulmonary carbon dioxide partial pressures as compared with the same exercise performed with unrestricted breathing (Kume et al., 2016;Toubekis et al., 2017;Woorons et al., 2007;Woorons et al., 2008;Woorons et al., 2010;Woorons et al., 2017). After several weeks of high-intensity VHL training, significant gains in anaerobic performance (Trincat et al., 2017;Woorons et al., 2016;Woorons et al., 2019a) and in repeated-sprint ability (RSA) (Ait Ali Braham et al., 2024;Brocherie et al., 2022;Fornasier Santos et al., 2018;Lapointe et al., 2020;Trincat et al., 2017;Woorons et al., 2019a;Woorons et al., 2020) have been reported in athletes of different sporting disciplines. ...
Purpose
To investigate the effects of a repeated-sprint training in hypoxia induced by voluntary hypoventilation at low lung volume (RSH-VHL) including end-expiratory breath holding (EEBH) of maximal duration.
Methods
Over a 4-week period, twenty elite judo athletes (10 women and 10 men) were randomly split into two groups to perform 8 sessions of rowing repeated-sprint exercise either with RSH-VHL (each sprint with maximal EEBH) or with unrestricted breathing (RSN, 10-s sprints). Before (Pre-), 5 days after (Post-1) and 12 days after (Post-2) the last training session, participants completed a repeated-sprint ability (RSA) test on a rowing ergometer (8 × 25-s “all-out” repetitions interspersed with 25 s of passive recovery). Power output (PO), oxygen uptake, perceptual-motor capacity (turning off a traffic light with a predetermined code), cerebral (Δ[Hbdiff]) and muscle (Δ[Hb/Mb]diff) oxygenation, cerebral total haemoglobin concentration (Δ[THb]) and muscle total haemoglobin/myoglobin concentration (Δ[THb/Mb]) were measured during each RSA repetition and/or recovery period.
Results
From Pre-to Post-1 and Post-2, maximal PO, mean PO (MPO) of the first half of the test (repetitions 1–4), oxygen uptake, end-repetition cerebral Δ[Hbdiff] and Δ[THb], end-repetition muscle Δ[Hb/Mb]diff and Δ[THb/Mb] and perceptual-motor capacity remained unchanged in both groups. Conversely, MPO of the second half of the test (repetitions 5–8) was higher at Post-1 than at Pre-in RSH-VHL only (p < 0.01), resulting in a lower percentage decrement score over the entire RSA test (20.4% ± 6.5% vs. 23.9% ± 7.0%, p = 0.01). Furthermore, MPO (5–8) was greater in RSH-VHL than in RSN at Post-1 (p = 0.04). These performance results were accompanied by an increase in muscle Δ[THb/Mb] (p < 0.01) and a concomitant decrease in cerebral Δ[THb] (p < 0.01) during the recovery periods of the RSA test at Post-1 in RSH-VHL.
Conclusion
Four weeks of RSH-VHL including maximal EEBH improved the ability of elite judo athletes to repeat high-intensity efforts. The performance improvement, observed 5 days but not 12 days after training, may be due to enhanced muscle perfusion. The unchanged oxygen uptake and the decrease in cerebral regional blood volume observed at the same time suggest that a blood volume redistribution occurred after the RSH-VHL intervention to meet the increase in muscle perfusion.
... This contributes to a decrease in cardiac output and low lung volume, which seems to cause a greater difference in O 2 concentration between arteries and alveoli and a consequent greater arterial O 2 desaturation (11). This latter apnea training mode also seems to lead to greater glycolytic activity, reflected in a higher lactate concentration and an earlier on-set of hypoxia, since in this case, hypercapnia is not a limiting factor and allows the establishment of hypoxemic conditions in the absence of a hypoxic environment (12). Differences can also be found as to whether apnea is static or dynamic. ...
López-Rebenaque O, Solís-Ferrer, Fierro-Marrero J, Asís-Fernández F. Acute effects of apnea bouts on hemoglobin concentration and hematocrit: a systematic review and meta-analysis. Undersea Hyperb Med. 2024 Second Quarter; 51(2):173-184. Objective: This study aimed to systematically analyze the existing literature and conduct a meta-analysis on the acute effects of apnea on the hematological response by assessing changes in hemoglobin (Hb) concentration and hematocrit (Hct) values. Methods: Searches in Pubmed, The Cochrane Library, and Web of Science were carried out for studies in which the main intervention was voluntary hypoventilation, and Hb and Hct values were measured. Risk of bias and quality assessments were performed. Results: Nine studies with data from 160 participants were included, involving both subjects experienced in breath-hold sports and physically active subjects unrelated to breath-holding activities. The GRADE scale showed a “high” confidence for Hb concentration, with a mean absolute effect of 0.57 g/dL over control interventions. “Moderate” confidence appeared for Hct, where the mean absolute effect was 2.45% higher over control interventions. Hb concentration increased to a greater extent in the apnea group compared to the control group (MD = 0.57 g/dL [95% CI 0.28, 0.86], Z = 3.81, p = 0.0001) as occurred with Hct (MD = 2.45% [95% CI 0.98, 3.93], Z = 3.26, p = 0.001). Conclusions: Apnea bouts lead to a significant increase in the concentration of Hb and Hct with a high and moderate quality of evidence, respectively. Further trials on apnea and its application to different settings are needed.
... Thus, the increased PaCO2 produced during exercise decreases pH and shifts the oxygen-hemoglobin dissociation curve to the right, and as a result also increases the frequency and range of respiration to return to normal through the process of hyperventilation, causing the activation of anaerobic metabolism and leading to an increased production of lactic acid. According to Woorons et al. [23], the mechanism of the neutralisation of lactic acid from NaHCO3 plasma leads to the production of lactate solution and the release of CO2, while this hypoxic-hypercapnic environment (e.g., ↓ oxygen saturation, ↓ pH, ↑ lactic acid, ↑ CO2 production, etc.) affects the quality of sleep [24]. ...
The aim of our study was to investigate the relationship between sleep quality and functional indices, swimming distance and gender in adolescent competitive swimmers. Forty-eight adolescent swimmers (boys, n = 22, 15.7 ± 1.0 years and girls, n = 26, 15.1 ± 0.8 years) were included in our study. They were assessed for handgrip strength, respiratory muscle strength and pulmonary function, answered a Pittsburg Sleep Quality Index questionnaire (PSQI), and recorded their anthropometric and morphological characteristics and training load for the last four weeks. The results showed differences between swimming distance and chest circumference difference, between maximal inhalation and exhalation (Δchest) (p = 0.033), PSQI score (p < 0.001), and sleep quality domains for “cannot breathe comfortably” (p = 0.037) and “have pain” (p = 0.003). Binary logistic regression (chi-square = 37.457, p = 0.001) showed that the variables Δchest (p = 0.038, 95% CI: 1.05–6.07) and PSQI score (p = 0.048, 95% CI: 0.1–1.07) remained independent predictors of the swim distance groups. Girls had a lower percentage of predicted values for the maximal inspiratory pressure (p < 0.001), maximal expiratory pressure (p = 0.027), forced expiratory volume within the first second (p = 0.026), forced vital capacity (p = 0.008) and sleep quality domains for “cough or snore loudly” (p = 0.032) compared to boys. A regression analysis showed that the sleep quality score was explained by the six independent variables: respiratory muscle strength (t = 2.177, β = 0.164, p = 0.035), Δchest (t = −2.353, β = −0.17, p = 0.023), distance (t = −5.962, β = −0.475, p < 0.001), total body water (t = −7.466, β = −0.687, p < 0.001), lean body mass (t = −3.120, β = −0.434, p = 0.003), and handgrip (t = 7.752, β = 1.136, p < 0.001). Our findings demonstrate that sleep quality in adolescent swimmers is a multifactorial result of morphometric characteristics, strength and respiratory function.
... Training with voluntary hypoventilation at low lung volume (VHL) is a method which consists of exercising while performing short bouts of end-expiratory breath holding (EEBH). Since 2007, this method has been consistently reported to acutely induce higher levels of blood and pulmonary carbon dioxide partial pressures as well as lower blood and muscle oxygenation compared with the same exercise performed with unrestricted breathing (Kume et al., 2016;Toubekis et al., 2017;Woorons et al., 2007Woorons et al., , 2010Woorons et al., , 2014Woorons et al., , 2017. Greater stimulation of anaerobic glycolysis, as a consequence of the hypoxic effect, has also been reported under this condition (Kume et al., 2016;Toubekis et al., 2017;Woorons et al., 2010Woorons et al., , 2014. ...
This study aimed to assess the physiological responses to repeated running exercise performed at supramaximal intensity and with end-expiratory breath holding (EEBH) up to the breaking point. Eight male runners participated in two running testing sessions on a motorized treadmill. In the first session, participants performed two sets of 8 repetitions at 125% of maximal aerobic velocity and with maximum EEBH. Each repetition started at the onset of EEBH and ended at its release. In the second session, participants replicated the same procedure, but with unrestricted breathing (URB). The change in cerebral and muscle oxygenation (Δ[Hbdiff]), total haemoglobin concentration (Δ[THb]) and muscle reoxygenation were continuously assessed. End-tidal oxygen (PETO2) and carbon dioxide pressure (PETCO2), arterial oxygen saturation (SpO2) and heart rate (HR) were also measured throughout exercise.On average, EEBH was maintained for 10.1 ± 1 s. At the breaking point of EEBH, PETO2 decreased to 54.1 ± 8 mmHg, whereas PETCO2 increased to 74.8 ± 3.1 mmHg. At the end of repetitions, SpO2 (nadir values 74.9 ± 5.0 vs. 95.7 ± 0.8%) and HR were lower with EEBH than with URB. Cerebral and muscle Δ[Hbdiff] were also lower with EEBH, whereas this condition induced higher cerebral and muscle Δ[THb] and greater muscle reoxygenation. This study showed that performing repeated bouts of supramaximal running exercises with EEBH up to the breaking point induced a fall in arterial, cerebral and muscle oxygenation compared with the URB condition. These phenomena were accompanied by increases in regional blood volume likely resulting from compensatory vasodilation to preserve oxygen delivery to the brain and muscles.
... For the practical methodological implementation, the question arises about the difference between holding the breath at high vs. low lung volume (i.e. after maximal inhalation or exhalation). Although breath-holding at high lung volume may help to simulate, to some extent, hypoxic conditions (Guimard et al., 2018;Joulia et al., 2003), only breath-holding at low lung volume creates fast physiological changes (i.e. a fast drop in arterial oxygen saturation) best mirroring hypoxic conditions to perform repeated sprints in hypoxia (Lapointe et al., 2020;Trincat et al., 2017;Woorons et al., 2007Woorons et al., , 2010Woorons et al., , 2017. Training repeated-sprint ability in hypoxia was found to provide better performance improvements in comparison to normoxic conditions . ...
Breathing techniques are predicted to affect specific physical and psychological states, such as relaxation or activation, that might benefit physical sport performance (PSP). Techniques include slow-paced breathing (SPB), fast-paced breathing (FBP), voluntary hyperventilation (VH), breath-holding (BH), and alternate- and uni-nostril breathing. A systematic literature search of six electronic databases was conducted in April 2022. Participants included were athletes and exercisers. In total, 37 studies were eligible for inclusion in the systematic review, and 36 were included in the five meta-analyses. Random effects meta-analyses for each breathing technique were computed separately for short-term and longer-term interventions. Results showed that SPB and BH were related to improved PSP, with large and small effect sizes for longer-term interventions, respectively. In short-term interventions, SPB, BH, and VH were unrelated to PSP. There was some evidence of publication bias for SPB and BH longer-term interventions, and 41% of the studies were coded as having a high risk of bias. Due to an insufficient number of studies, meta-analyses were not computed for other breathing techniques. Based on the heterogeneity observed in the findings, further research is required to investigate potential moderators and develop standardised breathing technique protocols that might help optimise PSP outcomes.
... specific logistic, cost). As an alternative, the use of voluntary hypoventilation at low lung volume (VHL), which consists in performing short bouts of end-expiratory breath holding while exercising, could induce severe drop (down to ∼87%) in arterial oxygen saturation (SpO 2 ) 14,15 leading to tissue hypoxia. 16,17 Although the hypoxic stimulus is not continuous when using this method, so that the physiological adaptations may not be similar to those of training in systemic hypoxia, exercise with VHL provides an additional physiological stress to produce greater or more rapid adaptations and consecutive performance enhancement compared to similar training in normoxia (i.e. with unrestricted breathing). ...
This study aimed to assess the effects of an off-season period of repeated-sprint training in hypoxia induced by voluntary hypoventilation at low lung volume (RSH-VHL) on off-ice re-peated-sprint ability (RSA) in ice hockey players.
Thirty-five high-level youth ice hockey players completed 10 sessions of running repeated sprints over a 5-week period, either with RSH-VHL (n =16) or with unrestricted breathing (RSN, n = 19). Before (Pre) and after (Post) the training period, subjects performed two 40-m single sprints (to obtain the reference velocity (Vref)) followed by a running RSA test (12 × 40 m all-out sprints with departure every 30 s).
From Pre to Post, there was no change in Vref or in the maximal velocity reached in the RSA test in both groups. In RSH-VHL, the mean velocity of the RSA test was higher (88.9 ± 5.4 vs. 92.9 ± 3.2 % of Vref; p < 0.01) and the percentage decrement score lower (11.1 ± 5.2 vs. 7.1 ± 3.3; p < 0.01) at Post than at Pre whereas no significant change occurred in the RSN group (89.6 ± 3.3 vs. 91.3 ± 1.9 % of Vref, p =0.11; 10.4 ± 3.2 vs. 8.7 ± 2.3 %; p = 0.13).
In conclusion, five weeks of off-ice RSH-VHL intervention led to a significant 4% improve-ment in off-ice RSA performance. Based on previous findings showing larger effects after shorter intervention time, the dose-response dependent effect of this innovative approach remains to be investigated.
... The maintenance of mean VO 2 between CONLD and CONLD-BH after the exercise on-transient response was supported not only by the microvasculature hemodynamic changes outlined earlier, but also by the increased VO 2 during the 25 s of regulated breathing (Table 4 and Figure 2A) and the reduced P ET O 2 immediately post-BH (Table 4 and Figure 2C) suggested earlier (Yamamoto et al., 1987). Specifically, Woorons et al. (2007) found that intermittent apneas performed at a high pulmonary volume (i.e., near total lung capacity) during higher intensity exercise (∼70% VO 2max ), similar to this study, maintained pulmonary arterial S at O 2 . ...
During competitive freestyle swimming, the change of direction requires a turn followed by ∼15 m of underwater kicking at various intensities that require a ∼5 s breath-hold (BH). Upon surfacing, breathing must be regulated, as head rotation is necessary to facilitate the breath while completing the length of the pool (∼25 s). This study compared the respiratory and muscle deoxygenation responses of regulated breathing vs. free breathing, during these 25–5 s cycles. It was hypothesized that with the addition of a BH and sprint during heavy-intensity (HVY) exercise, oxygen uptake (VO2) and oxygen saturation (SatO2) would decrease, and muscle deoxygenation ([HHb]) and total hemoglobin ([Hbtot]) would increase. Ten healthy male participants (24 ± 3 years) performed 4–6 min trials of HVY cycling in the following conditions: (1) continuous free breathing (CONLD); (2) continuous with 5 s BH every 25 s (CONLD-BH); (3) Fartlek (FLK), a 5 s sprint followed by 25 s of HVY; and (4) a combined Fartlek and BH (FLK-BH). Continuous collection of VO2 and SatO2, [Hbtot], and [HHb] via breath-by-breath gas analysis and near-infrared spectroscopy (normalized to baseline) was performed. Breathing frequency and tidal volumes were matched between CONLD and CONLD-BH and between FLK and FLK-BH. As a result, VO2 was unchanged between CONLD (2.12 ± 0.35 L/min) and CONLD-BH (2.15 ± 0.42 L/min; p = 0.116) and between FLK (2.24 ± 0.40 L/min) and FLK-BH (2.20 ± 0.45 L/min; p = 0.861). SatO2 was higher in CONLD (63 ± 1.9%) than CONLD-BH (59 ± 3.3%; p < 0.001), but was unchanged between FLK (61 ± 2.2%) and FLK-BH (62 ± 3.1%; p = 0.462). Δ[Hbtot] is higher in CONLD (3.3 ± 1.6 μM) than CONLD-BH (-2.5 ± 1.2 μM; Δ177%; p < 0.001), but was unchanged between FLK (2.0 ± 1.6 μM) and FLK-BH (0.82 ± 1.4 μM; p = 0.979). Δ[HHb] was higher in CONLD (7.3 ± 1.8μM) than CONLD-BH (7.0 ± 2.0μM; Δ4%; p = 0.011) and lower in FLK (6.7 ± 1.8μM) compared to FLK-BH (8.7 ± 2.4 μM; p < 0.001). It is suggested that the unchanged VO2 between CONLD and CONLD-BH was supported by increased deoxygenation as reflected by decreased Δ[Hbtot] and blunted Δ[HHb], via apneic-driven redistribution of blood flow away from working muscles, which was reflected by the decreased SatO2. However, the preserved VO2 during FLK-BH vs. FLK has been underpinned by an increase in [HHb].
... When hypoxia is induced by voluntary hypoventilation at a low lung volume (VHL), which causes relatively similar hypoxemia than altitude exposure (Woorons et al., 2007), encouraging results have been reported. In highly trained rugby players, for instance, RSH-VHL has shown larger improvements in repeated-sprint performance (∼60% more sprints on average during an exhaustive "open loop" test) than with an unrestricted breathing pattern (Fornasier-Santos et al., 2018). ...
With minimal costs and travel constraints for athletes, the “living low-training high” (LLTH) approach is becoming an important intervention for modern sport. The popularity of the LLTH model of altitude training is also associated with the fact that it only causes a slight disturbance to athletes' usual daily routine, allowing them to maintain their regular lifestyle in their home environment. In this perspective article, we discuss the evolving boundaries of the LLTH paradigm and its practical applications for athletes. Passive modalities include intermittent hypoxic exposure at rest (IHE) and Ischemic preconditioning (IPC). Active modalities use either local [blood flow restricted (BFR) exercise] and/or systemic hypoxia [continuous low-intensity training in hypoxia (CHT), interval hypoxic training (IHT), repeated-sprint training in hypoxia (RSH), sprint interval training in hypoxia (SIH) and resistance training in hypoxia (RTH)]. A combination of hypoxic methods targeting different attributes also represents an attractive solution. In conclusion, a growing number of LLTH altitude training methods exists that include the application of systemic and local hypoxia stimuli, or a combination of both, for performance enhancement in many disciplines.
... For instance, due to the UW nature AS competitions, practicing prolonged periods UW combined with intense muscle contraction could be utilized in combination with technical elements to improve overall AS performance. Previous studies in swimming has suggested short term periods of swimming with controlled/regulated breathing frequency or full apnea results in an elevated pulmonary function and capacity [73][74][75], which in turn may improve oxygen demand during periods UW through repeated periods of hypercapnia and the associated increase in P CO 2 and decrease in pH, all of which serve as mechanisms to encourage physiological adaptation [76][77][78]. In addition, other studies advocate the use of respiratory muscle training to improve pulmonary function and improve swimming performance [79]. ...
Artistic swimming (AS) is a very unique sport consisting of difficult artistically choreographed routines ranging in the number of athletes (one to ten: solo, duet, team, combination, highlight routine) and with elements performed quickly and precisely above, below, and on the surface of the water. As a result, the physical and physiological demands placed on an athlete are unique to the sport with the most pronounced adaptation being the bradycardic response to long apneic periods spent underwater while performing strenuous movements. This indeed influences training prescription and the desired training outcomes. This review paper explores the physiological demands of AS, the physiological characteristics that influence AS performance, and innovative approaches to enhancing training and performance in elite performers.
... 1:3 auf 1:5 bis 1:9 erhöht oder eine Strecke von 25-50m ohne zu atmen geschwommen [2,4]. Woorons et al. [15] ...
Background: High altitude training seems beneficial for
many athletes. However, training in altitude is always associated
with travel and high expenses. Thus, methods have
been developed to achieve similar effects as with high altitude
training. One method is voluntary hypoventilation training.
Although commonly used in training, the effectiveness
of this method has not been analysed sufficiently.
Methods: Intervention studies of voluntary hypoventilation
training were identified from searches in PubMed, SciVerse
Science Direct, Web of Science, Cochrane Library, EBSCOhost
and Google Scholar.
Results: Ten studies met the inclusion criteria. In seven studies,
an intervention of VHT lead to greater improvements of
the performance compared to a control programme.
Conclusions: The overall positive study results support the
usefulness of VHT for improving the performance and designing
a varied training. Due to the limited numbers of intervention
studies and the heterogeneous study designs, the
outcomes must be interpreted with caution.
... Despite the lack of physiological parameter modification, the swimmers perceived the exercise to be more difficult, as indicated by the higher RPE in apnoea than in NB. The cause of this higher perceived exertion could mainly relate, as suggested by Woorons et al. (2007), to the apnoea-induced hypercapnia (which brings about discomfort), combined with the longer duration of exercise. ...
The aim of this study was to determine the influence of swim intensity on acute responses to dynamic apnoea. 9 swimmers performed one 50 m front crawl trial in four different conditions: at 400 m velocity (V400) with normal breathing (NB), at V400 in complete apnoea (Ap), at maximal velocity (Vmax) with NB and at Vmax in Ap. Peak heart rate (HRpeak), blood lactate concentration after exercise (Lacpost ex) and Borg rating of perceived exertion (RPE) were measured. Arterial oxygen saturation (SpO2) was monitored with a pulse oximeter at forehead level during and after exercise. In Ap, swimming at V400 induced a significantly lower HRpeak and Lacpost ex than swimming at Vmax whilst RPE and the kinetics of SpO2 were not different at V400 and at Vmax. The minimal value of SpO2 in Ap was reached 10 to 11 s after the end of V400 and Vmax (81.7 ± 10.1% and 84.4 ± 10.6%, respectively). Swimming a 50 m front crawl in Ap resulted in a large decrease in SpO2 which occurred only after the cessation of exercise. The higher duration of apnoea during submaximal exercise could explain why SpO2 and RPE reached the same values as for maximal exercise.
... Such breathing rhythm enables them to swim mechanically more effectively (24,31) and therefore faster (5,31). Due to the occurrence of hypercapnia, respiratory and metabolic acidosis, reduced breathing frequency may lead to earlier occurrence of fatigue (16,44,45,48). Increases in arterial PCO2 stimulate breathing through both, the carotid bodies and the central chemoreceptors. ...
Abstract
The aim of the present study was to determine the effects of an 8-week hypercapnic-hypoxic (H-H or apnea) training program on respiratory muscles strength and 100 meter crawl swimming performance. The study was conducted on a sample of 26 elite Croatian swimmers (experimental group [EG] n=12, control group [CG] n=14). Both groups were subjected to the same swimming training programs and training sessions on a treadmill. The experimental group was additionally subjected to hypercapnic-hypoxic training program with increased muscular activity. Data on the following outcome variables was collected: the strength of respiratory muscles (maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP)), 100m front crawl swimming time (R100m) and breathing frequency during the same test (BF100m). A series of two way repeated measures ANOVAs has shown significant interactions between group (EG and CG) and the repeated-measure factor (pre- and post-test) (MIP: p = 0.006, MEP: p < 0.001, R100m, p < 0.001, FB100m, p < 0.001), all showing greater efficacy of the experimental program. It seems that the hypercapnic-hypoxic training program may provide substantial benefits for elite swimmers, in addition to their standard training sessions.
... Such breathing rhythm enables them to swim mechanically more effectively (24,31) and therefore faster (5,31). Due to the occurrence of hypercapnia, respiratory and metabolic acidosis, reduced breathing frequency may lead to earlier occurrence of fatigue (16,44,45,48). Increases in arterial PCO2 stimulate breathing through both, the carotid bodies and the central chemoreceptors. ...
The aim of the present study was to determine the effects of an 8-week hypercapnic-hypoxic (H-H or apnea) training program on respiratory muscles strength and 100 meter crawl swimming performance. The study was conducted on a sample of 26 elite Croatian swimmers (experimental group [EG] n=12, control group [CG] n=14). Both groups were subjected to the same swimming training programs and training sessions on a treadmill. The experimental group was additionally subjected to hypercapnic-hypoxic training program with increased muscular activity. Data on the following outcome variables was collected: the strength of respiratory muscles (maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP)), 100m front crawl swimming time (R100m) and breathing frequency during the same test (BF100m). A series of two way repeated measures ANOVAs has shown significant interactions between group (EG and CG) and the repeated-measure factor (pre- and post-test) (MIP: p = 0.006, MEP: p < 0.001, R100m, p < 0.001, FB100m, p < 0.001), all showing greater efficacy of the experimental program. It seems that the hypercapnic-hypoxic training program may provide substantial benefits for elite swimmers, in addition to their standard training sessions.
... However, there are reports indicating that hypoxia may occur during maximal and submaximal intensity swimming (Miyasaka et al., 2002;Woorons et al., 2014). In land exercise, repeated apnea or expiration close to the residual volume may contribute to progressive reduction of O2 saturation and this may be also accompanied by hypercapnia (deBruijn et al., 2008;Woorons et al., 2007;Woorons et al., 2010). Nevertheless, combined effects of hypoxia and hypercapnia in addition to dynamic apneic conditions have to be considered when trying to explain the improved performance in the 400 m test in the present study. ...
The purpose of this study was to examine the effects of training with intermittent breath holding (IBH) on respiratory parameters, arterial oxygen saturation (SpO2) and performance. Twenty-eight fin-swimming athletes were randomly divided into two groups and followed the same training for 16 weeks. About 40% of the distance of each session was performed with self-selected breathing frequency (SBF group) or IBH (IBH group). Performance time of 50 and 400 m at maximum intensity was recorded and forced expired volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and SpO2 were measured before and after the 50 m test at baseline and post-training. Posttraining, the respiratory parameters were increased in the IBH but remained unchanged in the SBF group (FEV1: 17 ±15% vs. -1 ±11%; FVC: 22 ±13% vs. 1 ±10%; PEF: 9 ±14% vs. -4 ±15%; p<0.05). Pre compared to post-training SpO2 was unchanged at baseline and decreased post-training following the 50 m test in both groups (p<0.05). The reduction was higher in the IBH compared to the SBF group (p<0.05). Performance in the 50 and 400 m tests improved in both groups, however, the improvement was greater in the IBH compared to the SBF group in both 50 and 400 m tests (p<0.05). The use of IBH is likely to enhance the load on the respiratory muscles, thus, contributing to improvement of the respiratory parameters. Decreased SpO2 after IBH is likely due to adaptation to hypoventilation. IBH favours performance improvement at 50 and 400 m fin-swimming.
... Such breathing rhythm enables them to swim mechanically more effectively (24,31) and therefore faster (5,31). Due to the occurrence of hypercapnia, respiratory and metabolic acidosis, reduced breathing frequency may lead to earlier occurrence of fatigue (16,44,45,48). Increases in arterial PCO2 stimulate breathing through both, the carotid bodies and the central chemoreceptors. ...
Introduction. Hypercapnia is known as a powerful cerebral vasodilator and ventilatory stimulants and represents an elevated partial pressure of carbon dioxide (pCO2) in arterial blood (Ivancev, 2009). Breathing muscles work while swimming is less economical because they have to, because of the short breaths; contract faster to gain a greater respiratory volume (Kapus, 2008). Specifically, breathing is difficult because the muscles involved in breathing performed additional work (Lomax & McConnell, 2003). The aim of this research is to determine the effects of hypercapnic-hypoxic training on result at 100 meters crawl swimming, together with determining respiratory muscles strength.
Methods . In order to collect data testing is carried out on 26 top swimmers (control (C, n = 14) and experimental (E, n = 12)) in the following tests: the strength of respiratory muscles, the result of the 100m freestyle swim and the number of breaths during that race.
Results. Results based on Wilks'Lambda = 0.42790, p = 0.000 at significant level p<0.05, we see that there is a statistically significant difference in multivariate space progress between groups "repeated measures MANOVA". A series of two-way univariate analysis of variance "repeated measures ANOVA" showed that all the variables show statistically significant differences in progress between groups (MIP, p = 0.006, MEP, p <0.0001, R100, p <0.0001, FB, p = 0.000).
Discussion. Because of the increased strength of respiratory muscles in swimmers of experimental group it is possible that there was an increased volume of breathing with each inhale and exhale. Greater amount of air in the lungs has a positive effect on the amount of oxygen available, the elimination of excess CO2 and the very buoyancy of swimmers. They were also able to achieve better result in 100m crawl swim as well as a reduced number of breaths during that swim. Breathing during swimming interferes with propulsion and causes time imbalance between the two strokes and is recommended for swimmers (Lerda et al., 2001; Seifert et al., 2007), especially in shorter races to try to swim with the smaller number of breaths
... A practice in free-diving results in spleen contraction , which enhances the oxygen transfer, increases the erythrocyte count, hematocrit level and hemoglobin concentration (Schagaty, et al., 2005; Prommer, et al., 2007 ). Previously conducted research studies (Woorons, et al., 2005Woorons, et al., , 2007) have shown that the type of an intermittent hypercapnic-hypoxic training influences arterial desaturation , induces hypercapnia and thus enhances the buffer capacity. However, it has not yet been proven that the hypercapnic-hypoxic training program improves hematological parameters and aerobic performance . ...
The aim of this research was to establish the effects of the 8-week hypercapnic-hypoxic training program on hemoglobin concentration (Hb) and the maximum oxygen uptake (VO2max) in swimmers. The research was conducted on a sample of 16 Croatian elite male swimmers (experimental group n=8, control group n=8). Both groups were subjected to the same swimming trainings and additional training sessions on a treadmill. The experimental group was subjected additionally to hypercapnic-hypoxic training program with enhanced muscular activity. The experiment lasted for eight weeks. The following variables were used: hemoglobin concentration (Hb) and maximum oxygen uptake (VO2max). The ANOVA series application for the repeated measurements have shown significant Hb and VO2max concentration differences related to the effect of both
groups. The hypercapnic-hypoxic training method, which was applied to elite swimmers, has resulted in a 5.35% higher Hb concentration at the end of the program, which also caused a 10.79% increase in the VO2max.
Keywords
hypercapnic-hypoxic training; hemoglobin concentration; maximum oxygen uptake; swimmers
... Since brief intermittent hypoxia exposures (IHE) have been shown to increase HVR r and HVR e (Katayama et al., 2001), IHE might therefore be considered as an effective acclimatization strategy to reduce the risk for high-altitude disorders during high altitude exposure (Wille et al., 2012). Recent studies suggest that training with voluntary hypoventilation-induced IHE could be an interesting way for athletes to benefit from intermittent hypoxia without going to altitude or using expensive devices to simulate the hypoxic environment (Woorons et al., 2007(Woorons et al., , 2010. We thus hypothesized that trained BHDs would have greater HVR r and HVR e compared with a control group, due to increases in both minute ventilation (V E ) and arterial oxygen saturation (SaO 2 ); we further hypothesized that these responses might also be associated with blunted HCVR. ...
tTrained breath-hold divers (BHDs) are exposed to repeated bouts of intermittent hypoxia and hyper-capnia during prolonged breath-holding. It has thus been hypothesized that their specific training maydevelop enhanced chemo-responsiveness to hypoxia associated with reduced ventilatory response tohypercapnia.Hypercapnic ventilatory responses (HCVR) and hypoxic ventilatory responses at rest (HVRr) and exer-cise (HVRe) were assessed in BHDs (n = 7) and a control group of non-divers (NDs = 7). Cardiac output (CO),stroke volume (SV) and heart rate (HR) were also recorded. BHDs presented carbon dioxide sensitivitysimilar to that of NDs (2.85 ± 1.41 vs. 1.85 ± 0.93 L min−1mmHg−1, p > 0.05, respectively). However, bothHVRr(+68%) and HVRe(+31%) were increased in BHDs. CO and HR reached lower values in BHDs thanNDs during the hypoxic exercise test.These results suggest that the exposure to repeated bouts of hypoxia/hypercapnia frequently experi-enced by trained breath-hold divers only enhances their chemo-responsiveness to poikilocapnic hypoxia,without altering HCVR.
... Since brief intermittent hypoxia exposures (IHE) have been shown to increase HVR r and HVR e (Katayama et al., 2001), IHE might therefore be considered as an effective acclimatization strategy to reduce the risk for high-altitude disorders during high altitude exposure (Wille et al., 2012). Recent studies suggest that training with voluntary hypoventilation-induced IHE could be an interesting way for athletes to benefit from intermittent hypoxia without going to altitude or using expensive devices to simulate the hypoxic environment (Woorons et al., 2010;Woorons et al., 2007). We thus hypothesized that trained BHDs would have greater HVR r and HVR e compared with a control group, due to increases in both minute ventilation (V E ) and arterial oxygen saturation (SaO 2 ); we further hypothesized that these responses might also be associated with blunted HCVR. ...
Trained breath-hold divers (BHDs) are exposed to repeated bouts of intermittent hypoxia and hypercapnia during prolonged breath-holding. It has thus been hypothesized that their specific training may develop enhanced chemo-responsiveness to hypoxia associated with reduced ventilatory response to hypercapnia. Hypercapnic ventilatory responses (HCVR) and hypoxic ventilatory responses at rest (HVRr) and exercise (HVRe) were assessed in BHDs (n=7) and a control group of non-divers (NDs=7). Cardiac output (CO), stroke volume (SV) and heart rate (HR) were also recorded. BHDs presented carbon dioxide sensitivity similar to that of NDs (2.85±1.41 vs. 1.85±0.93 l.min(-1).mmHg(-1), p>0.05, respectively). However, both HVRr (+68%) and HVRe (+31%) were increased in BHDs. CO and HR reached lower values in BHDs than NDs during the hypoxic exercise test. These results suggest that the exposure to repeated bouts of hypoxia/hypercapnia frequently experienced by trained breath-hold divers only enhances their chemo-responsiveness to poikilocapnic hypoxia, without altering HCVR.
... Atypical Antipsychotics are very useful in the treatment of schizophrenia and occasionally in the treatment of severe aggressive behaviors. But hyperprolactinemia, particularly in women and also in men, has been associated to treatment with both typical and atypical antipsychotics such as risperidone and probably to others [1][2][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. ...
... There is mounting evidence of arterial hypoxemia in athletes during submaximal exercise [11] and in endurancetrained athletes [12]. Prevalence of exercise-induced arterial hypoxemia (EIAH) ranges from 50% [13] to 67% [14]. ...
Doping with erythropoietic proteins such as erythropoietin (EPO) is a serious issue in sport. There is little information on the possible ophthalmologic alterations followed by frequent EPO abuse in athletes. EPO is a potent retinal angiogenic factor and is capable of stimulating retinal angiogenesis and neovascularization in the presence of ischemia. Systemic and intravitreal EPO concentrations are highly correlated. A linkage between EPO doping and retinal proliferation is possible and further studies are warranted. Gathering and analyzing data on retinal findings from these athletes, either retrospectively or prospectively might yield preliminary information to support the safety of those athletes. Implications of this hypothesis cover other kinds of neovascularizations and angiogenesis.
... Very recently, two studies have demonstrated that it could be possible to get a significant arterial desaturation during exercise without being placed in an hypoxic environment. [113,114] This is actually possible by voluntarily reducing the breathing frequency and by holding one's breath at low pulmonary volumes. Thus, repeatedly using this respiratory technique during training would represent an intermittent hypoxic exposure and could therefore be likened to IHT, although hypoventilation also induces hypercapnia. ...
New methods and devices for pursuing performance enhancement through altitude training were developed in Scandinavia and the USA in the early 1990s. At present, several forms of hypoxic training and/or altitude exposure exist: traditional ‘live high-train high’ (LHTH), contemporary ‘live high-train low’ (LHTL), intermittent hypoxic exposure during rest (IHE) and intermittent hypoxic exposure during continuous session (IHT). Although substantial differences exist between these methods of hypoxic training and/ or exposure, all have the same goal: to induce an improvement in athletic performance at sea level. They are also used for preparation for competition at altitude and/or for the acclimatization of mountaineers.
The underlying mechanisms behind the effects of hypoxic training are widely debated. Although the popular view is that altitude training may lead to an increase in haematological capacity, this may not be the main, or the only, factor involved in the improvement of performance. Other central (such as ventilatory, haemodynamic or neural adaptation) or peripheral (such as muscle buffering capacity or economy) factors play an important role.
LHTL was shown to be an efficient method. The optimal altitude for living high has been defined as being 2200–2500 m to provide an optimal erythropoietic effect and up to 3100m for non-haematological parameters. The optimal duration at altitude appears to be 4 weeks for inducing accelerated erythropoiesis whereas <3 weeks (i.e. 18 days) are long enough for beneficial changes in economy, muscle buffering capacity, the hypoxic ventilatory response or Na+/K+-ATPase activity. One critical point is the daily dose of altitude. A natural altitude of 2500 m for 20–22 h/day (in fact, travelling down to the valley only for training) appears sufficient to increase erythropoiesis and improve sea-level performance. ‘Longer is better’ as regards haematological changes since additional benefits have been shown as hypoxic exposure increases beyond 16 h/day. The minimum daily dose for stimulating erythropoiesis seems to be 12 h/day. For non-haematological changes, the implementation of a much shorter duration of exposure seems possible.
Athletes could take advantage of IHT, which seems more beneficial than IHE in performance enhancement. The intensity of hypoxic exercise might play a role on adaptations at the molecular level in skeletal muscle tissue. There is clear evidence that intense exercise at high altitude stimulates to a greater extent muscle adaptations for both aerobic and anaerobic exercises and limits the decrease in power. So although IHT induces no increase in V̇O2max due to the low‘altitude dose’, improvement in athletic performance is likely to happenwith high-intensity exercise (i.e. above the ventilatory threshold) due to an increase in mitochondrial efficiency and pH/lactate regulation. We propose a new combination of hypoxic method (which we suggest naming Living High-Training Low and High, interspersed; LHTLHi) combining LHTL (five nights at 3000 m and two nights at sea level) with training at sea level except for a few (2.3 per week) IHT sessions of supra-threshold training. This review also provides a rationale on how to combine the different hypoxic methods and suggests advances in both their implementation and their periodization during the yearly training programme of athletes competing in endurance, glycolytic or intermittent sports.
Purpose
To investigate the impact of voluntary hypoventilation at low lung volumes (VHL) during upper body repeated sprints (RS) on performance, metabolic markers and muscle oxygenation in Brazilian Jiu-Jitsu (BJJ) athletes.
Methods
Eighteen male well-trained athletes performed two randomized RS sessions, one with normal breathing (RSN) and another with VHL (RS-VHL), on an arm cycle ergometer, consisting of two sets of eight all-out 6-s sprints performed every 30 s. Peak (PPO), mean power output (MPO), and RS percentage decrement score were calculated. Arterial oxygen saturation (SpO2), heart rate (HR), gas exchange, and muscle oxygenation of the long head of the triceps brachii were continuously recorded. Blood lactate concentration ([La]) was measured at the end of each set. Bench press throw peak power (BPPP) was recorded before and after the RS protocol.
Results
Although SpO2 was not different between conditions, PPO and MPO were significantly lower in RS-VHL. E, HR, [La], and RER were lower in RS-VHL, and VO2 was higher in RS-VLH than in RSN. Muscle oxygenation was not different between conditions nor was its pattern of change across the RS protocol influenced by condition. [La] was lower in RS-VHL than in RSN after both sets.
Conclusion
Performance was significantly lower in RS-VHL, even though SPO2 was not consistent with hypoxemia. However, the fatigue index was not significantly affected by VHL, nor was the neuromuscular upper body power after the RS-VHL protocol. Additionally, [La] was lower, and oxygen consumption was higher in RS-VHL, suggesting a higher aerobic contribution in this condition.
Purpose: To investigate the effects of a repeated-sprint training with voluntary hypoventilation at low (RSH-VHL) and high (RS-VHH) lung volume on repeated-sprint ability (RSA) in female athletes. Methods: Over a six-week period, 24 female soccer players completed 12 sessions of repeated 30-m running sprints either with end-expiratory breath holding (RSH-VHL, n=8), end-inspiratory breath holding (RS-VHH, n=8) or unrestricted breathing (RS-URB, n=8). Before (Pre) and after (Post) training, a running RSA test consisting of performing 30-m all-out sprints until exhaustion was implemented. Results: From Pre to Post, the number of sprints completed during the RSA test was increased in both RSH-VHL (19.3±0.9 vs. 22.6±0.9; p<0.01) and RS-VHH (19.3±1.5 vs. 20.5±1.7; p<0.01) but not in RS-URB (19.4±1.3 vs.19.5±1.7; p=0.67). The mean velocity and the percentage decrement score calculated over sprint 1 to 17 were respectively higher (82.2 ± 1.8 vs. 84.6 ± 2.1% of maximal velocity) and lower (23.7±3.1 vs. 19.4±3.2%) in RSH-VHL (p<0.01) whereas they remained unchanged in RS-VHH and RS-URB. The mean arterial oxygen saturation recorded during training at the end of the sprints was lower in RSH-VHL (92.1±0.4%) than in RS-VHH (97.3±0.1 %) and RS-URB (97.8±0.1%). Conclusions: This study shows that female athletes can benefit from the RSH-VHL intervention to improve RSA. The performance gains may have been limited by the short sprinting distance with end-expiratory breath holding which provoked only moderate hypoxaemia. The increase in the number of sprints in RS-VHH seems to show that factors other than hypoxia may have played a role in RSA improvement.
Purpose : Repeated-sprint training in hypoxia (RSH) has been shown as an efficient method for improving repeated sprint ability (RSA) in team-sport players but has not been investigated in swimming. We assessed whether RSH with arterial desaturation induced by voluntary hypoventilation at low lung volume (VHL) could improve RSA to a greater extent than the same training performed under normal breathing (NB) conditions. Methods : 16 competitive swimmers completed six sessions of repeated sprints (two sets of 16×15 m with 30 s send-off) either with VHL (RSH-VHL, n=8) or with NB (RSN, n=8). Before (pre-) and after (post-) training, performance was evaluated through an RSA test (25m all-out sprints with 35 s send-off) until exhaustion. Results : From pre- to post-, the number of sprints was significantly increased in RSH-VHL (7.1 ± 2.1 vs 9.6 ± 2.5; p<0.01) but not in RSN (8.0 ± 3.1 vs 8.7 ± 3.7; p=0.38). Maximal blood lactate concentration ([La]max) was higher at post compared to pre- in RSH-VHL (11.5 ± 3.9 vs 7.9 ± 3.7 mmol.l-137 ; p=0.04) but was unchanged in RSN (10.2 ± 2.0 vs 9.0 ± 3.5 mmol.l-138 ; p=0.34). There was a strong correlation between the increases in the number of sprints and in [La]max in RSH-VHL only (R=0.93; p<0.01).
Conclusion : Repeated sprint training in hypoxia induced by voluntary hypoventilation at low lung volume improved repeated sprint ability in swimming, probably through enhanced anaerobic glycolysis. This innovative method allows inducing benefits normally associated with hypoxia during swim training in normoxia.
Purpose: This study aimed to determine whether hypoventilation training at supramaximal intensity could improve swimming performance more than the same training carried out under normal breathing conditions.
Methods: Over a 5-week period, sixteen triathletes (12 men, 4 women) were asked to include twice a week into their usual swimming session one supramaximal set of 12 to 20 x 25m, performed either with hypoventilation at low lung volume (VHL group) or with normal breathing (CONT group). Before (Pre-) and after (Post-) training, all triathletes performed all-out front crawl trials over 100, 200 and 400m.
Results: Time performance was significantly improved in VHL in all trials [100m: - 3.7 ± 3.7s (- 4.4 ± 4.0%); 200m: - 6.9 ± 5.0s (- 3.6 ± 2.3%); 400m: - 13.6 ± 6.1s (-3.5 ± 1.5%)] but did not change in CONT. In VHL, maximal lactate concentration (+ 2.35 ± 1.3 mmol.L-1 on average) and the rate of lactate accumulation in blood (+ 41.7 ± 39.4%) were higher at Post- than at Pre- in the three trials whereas they remained unchanged in CONT. Arterial oxygen saturation, heart rate, breathing frequency and stroke length were not altered in both groups at the end of the training period. On the other hand, stroke rate was higher at Post- compared to Pre- in VHL but was not different in CONT. The measurements of gas exchange over the 400-m trial revealed no change in peak oxygen consumption as well as in any pulmonary variable in both groups.
Conclusion: This study demonstrated that VHL training, when performed at supramaximal intensity, represents an effective method for improving swimming performance, partly through an increase in the anaerobic glycolysis activity.
Aim:
This study examined the effect of intermittent breath holding (IBH) on physiological response, including oxygenation in working muscle, to moderate-intensity exercise.
Methods:
Thirteen men performed bicycle exercise for 5 min at 65% of peak oxygen uptake with normal breathing (NB) and with IBH. Muscle oxygenation, concentration changes of oxyhemoglobin (ΔOxy-Hb), deoxyhemoglobin (ΔDeoxy-Hb) and total hemoglobin (ΔTotal-Hb), in the right vastus lateralis were continuously monitored using near-infrared spectroscopy (NIRS). Finger capillary blood samples were taken after exercise for analyzing blood lactate concentration (BLa).
Results:
NIRS parameters showed acute changes to each BH episode in the IBH condition (Total-Hb and ΔOxy-Hb decreased, ΔDeoxy-Hb increased). Accordingly, in the IBH condition, ΔOxy-Hb was lower (P<0.05) and ΔDeoxy-Hb was higher (P<0.05) compared to that in the NB condition, whereas there was no difference in ΔTotal-Hb in the both conditions. BLa levels were greater (P<0.05) in the IBH condition compare to the NB condition.
Conclusion:
These results suggest that IBH during moderate-intensity exercise provokes consistent changes in muscle oxygenation, leading to lower tissue oxygenation. Our data also indicate that exercise with IBH induces higher BLa.
Atypical antipsychotic-induced hyperprolactinemia can cause important clinical symptoms, particularly in young women and also in men, such as impotence, loss of libido, gynecomastia, anovulation and galactorrhea.
Observational over one-year follow-up of six patients (four women and two men, mean age of 31.1 years, range 26-37), treated with different atypical antipsychotics in an outpatient psychiatric device, who had clinical complications associated to high prolactin serum levels. All of them were treated with standard doses of cabergoline.
Most patients experienced significant clinical improvement after treatment with standard doses of cabergoline (mean dosage 1.08 mg/week), maintained for a mean of 18 month. Normal prolactin levels were achieved after the first months of treatment with cabergoline. No side effects or worsening of psychotic or behavioral symptoms were observed.
Long-term treatment with cabergoline seems to be safe in atypical antipsychotic-treated patients.
This study aimed to determine the cardiovascular responses during a prolonged exercise with voluntary hypoventilation (VH). 7 men performed 3 series of 5-min exercise at 65% of normoxic maximal O (2) uptake under 3 conditions: (1) normal breathing (NB) in normoxia (NB (0.21)), (2) VH in normoxia (VH (0.21)), (3) NB in hypoxia (NB (0.157), inspired oxygen fraction=0.157). In both VH (0.21) and NB (0.157), there was a similar drop in arterial oxygen saturation and arterial O (2) content (CaO (2)) which were lower than in NB (0.21). Heart rate (HR), stroke volume, and cardiac output (-) were higher in VH (0.21) than in NB (0.21) during most parts of exercise whereas there was no difference between NB (0.157) and VH (0.21) or NB (0.21). HR variability analysis suggested an increased sympathetic modulation in VH (0.21) only. O (2) transport and oxygen uptake were generally not different between interventions. Mixed venous O (2) content (C-O (2)) was lower in NB (0.157) than in both VH (0.21) and NB (0.21) and not different between the latter. CaO (2)-C-O (2) was not different between NB (0.157) and NB (0.21) but lower in VH (0.21). This study shows that a prolonged exercise with VH leads to a greater cardiac activity, independent from the hypoxic effect. The greater - in VH compared to normal breathing seems to be the main factor for compensating the drop of arterial oxygen content.
Metabolic and cardiorespiratory responses of swimmers were compared during a 'hypoxic swim training' session with those during a training session with normal breathing. 'Hypoxic swimming' in the sense used by most coaches is defined as swimming with controlled breathing, i.e., by breathing less often. During 10 x 100 m repeats, as well as during 5 x 200 m repeats, heart rates and blood lactate levels were significantly lower with controlled swimming than with normal swimming. End-tidal oxygen and carbon dioxide tensions were on the average 77 and 56 mmHg, respectively, during the 10 x 100 m repeats; this finding indicates severe hypercapnia conditions rather than true hypoxic conditions. Similar, but less extreme, values were obtained during the 5 x 200 m with controlled breathing. The 5 x 200 m protocol was also performed in a swimming flume by five swimmers. Oxygen uptake, pulmonary ventilation, and expired oxygen concentration were significantly lower during the controlled repeats compared with normal repeats. Heart rates and blood lactate values were not significantly different under the two breathing conditions. Our results lend no support to the view that hypoxic swim training has an advantage over normal swim training in increasing aerobic or anaerobic power. On the other hand, it is suggested that controlled breathing per se might have acute biomechanical effect, improving stroke mechanics and reducing drag.
Arterialized ear lobe blood samples have been described as adequate togauge gas exchange in acute and chronically ill patients. It is a safe procedure, usually performed by medical technicians. We have conducted a prospective study toverify the validity of this method. One hundred and fifteen consecutive adult patients were studied. Blood samples were drawn simultaneously from arterialized earlobe and radial artery. Values of partial pressure of oxygen ,(PO2) and of carbon ,dioxide (PCO2) were measured by means of blood gas electrodes. The correlation coefficients between the two samples were 0.928 for PO2 and 0.957 for PCO2 values. In spite of a highly significant correlation, the limits of agreement between the two methods were wide for PO2. Earlobe values of PO2 were usually lower than arterial values, with larger differences in the range of normal arterial PO2. Onthe other hand, the error and the limits of agreement were smaller for PCO2. Weconclude that, in adult patients, arterialized earlobe blood PO2 is not a reli- able mirror of arterial PO2. Eur Respir J., 1996, 9: 186‐189. Division de Pneumologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland Correspondence: J.W. Fitting
The intention of this study was to determine the metabolic consequences of reduced frequency breathing (RFB) at total lung capacity (TLC) in competitive cyclists during submaximal exercise at moderate altitude (1520 m; barometric pressure, P
B=84.6 kPa; 635 mm Hg). Nine trained males performed an RFB exercise test (10 breaths · min −1) and a normal breathing exercise test at 75–85% of the ventilatory threshold intensity for 6 min on separate days. RFB exercise induced significant (P<0.05) decreases in ventilation (V
E), carbon dioxide production (VCO2), respiratory exchange ratio. (RER), ventilatory equivalent for O2 consumption (V
E/VO2), arterial O2 saturation and increases in heart rate and venous lactate concentration, while maintaining a similar OZ consumption (VO2). During recovery from RFB exercise (spontaneous breathing) a significant (P< 0.05) decrease in blood pH was detected along with increases in V
E, VO2, VCO2, RER, and venous partial pressure of carbon dioxide. The results indicate that voluntary hypoventilation at TLC, during submaximal cycling exercise at moderate altitude, elicits systemic hypercapnia, arterial hypoxemia, tissue hypoxia and acidosis. These data suggest that RFB exercise at moderate altitude causes an increase in energy production from glycolytic pathways above that which occurs with normal breathing.
To compare two situations with similar magnitudes of mitochondrial substrate flux but different blood oxygen contents, one-legged training was employed. Ten healthy subjects trained one leg under normobaric conditions and the other under hypobaric conditions. At each session the subjects trained each leg for 30 min. The absolute work intensity was the same for both legs and was chosen to correspond to 65% of the average (right and left) pretraining one-legged maximal work capacity. There were three to four training sessions per week for 4 wk. Muscle biopsies from each leg were taken before and after training and analyzed for fiber types, capillaries, myoglobin, and oxidative and glycolytic enzymes. The most striking finding was a greater increase of citrate synthase activity under hypobaric conditions than under normobaric conditions. In addition, the myoglobin content increased in the leg trained under hypobaric conditions, whereas it tended to decrease in the normobarically trained leg. Because both legs were trained at the same intensity, the oxygen turnover and the substrate flux through the carboxylic acid cycle and the respiratory chain must have been of similar magnitude. Thus a difference in substrate flux is less likely to have caused the differences in enzyme activities and myoglobin content between training under normobaric and hypobaric conditions. Instead, the stimulus seems to be related to the blood oxygen content or tension.
Sampling arterialized earlobe blood is thought to be easier and less painful than direct arterial puncture, and to allow measurement of blood gas values during exercise without the need to insert an arterial cannula. However, arterialized earlobe oxygen tension (PO2) often underestimates arterial PO2 at rest, and is not fully validated during exercise. We have therefore conducted a prospective study to compare values of PO2 and carbon dioxide tension (PCO2) and the discomfort experienced by adult subjects undergoing the two methods of blood sampling during exercise. Seventy consecutive adult patients were studied. Blood samples were drawn simultaneously from the radial artery and arterialized earlobe of each patient during the last minute of an 8 min exercise. Values of PO2 and PCO2 were measured by means of blood gas electrodes. The correlation coefficients between the two samples were 0.92 for PO2 and 0.91 for PCO2. However, the bias and the limits of agreement between the two methods were wide for PO2 (mean+/-2SD of the differences between the two methods: 0.63+/-1.50 kPa (4.7+/-11.2 mmHg)). The bias and the limits of agreement were smaller for PCO2. Patients felt that the earlobe method was not associated with less discomfort than radial artery puncture. We conclude that arterialized earlobe blood oxygen tension is not a good substitute for arterial oxygen tension during exercise, and should not be used to assess arterial oxygen tension in adults during exercise.
This study was conducted to determine whether arterial desaturation would occur at submaximal workloads in highly trained endurance athletes and whether saturation is affected by the fraction of oxygen in inspired air (F(I)O2). Six highly trained endurance athletes (5 women and 1 man, aged 25+/-4 yr, VO2max 71.3+/-5.0 ml x kg(-1) x min(-1)) ran 4x4 min on a treadmill in normoxia (F(I)O2 0.209), hypoxia (F(I)O2 0.155) and hyperoxia (F(I)O2 0.293) in a randomized order. The running velocities corresponded to 50, 60, 70 and 80% of their normoxic maximal oxygen uptake (VO2max). In hypoxia, the arterial haemoglobin oxygen saturation percentage (SpO2%) was significantly lower than in hyperoxia and normoxia throughout the test, and the difference became more evident with increasing running intensity. In hyperoxia, the SpO2% was significantly higher than in normoxia at 70% running intensity as well as during recovery. The lowest values of SpO2% were 94.0+/-3.8% (P<0.05, compared with rest) in hyperoxia, 91.0+/-3.6% (P<0.001) in normoxia and 72.8+/-10.2% (P<0.001) in hypoxia. Although the SpO2% varied with the F(I)O2, the VO2 was very similar between the trials, but the blood lactate concentration was elevated in hypoxia and decreased in hyperoxia at the 70% and 80% workloads. In conclusion, elite endurance athletes may show an F(I)O2-dependent limitation for arterial O2 saturation even at submaximal running intensities. In hyperoxia and normoxia, the desaturation is partly transient, but in hypoxia the desaturation worsens parallel with the increase in exercise intensity.
The goal of this study was to investigate to what extent intermittent exposure to altitude in a hypobaric chamber can improve performance at sea-level. Over a 10-day period, elite male triathletes trained for 2 h each day on a cycle ergometer placed in a hypobaric chamber. Training intensity was 60–70% of the heart rate reserve. Eight subjects trained at a simulated altitude of 2.500 m (hypoxia group), the other eight remained at sea-level (sea-level group). Baseline measurements were done on a cycle ergometer at sea-level, which included an incremental test until exhaustion and a Wingate Anaerobic Test. Nine days after training in hypoxia, significant increases were seen in all important parameters of the maximal aerobic as well as the anaerobic test. A significant increase of 7.0% was seen in the mean maximal oxygen uptake per kilogram body weight (
), and the mean maximal power output per kilogram body weight (W
max) increased significantly by 7.4%. The mean values of both mean power per kilogram body weight and peak power per kilogram body weight increased significantly by 5.0%, and the time-to-peak decreased significantly by 37.7%. In the sea-level group, no significant changes were seen in the above-mentioned parameters of both the maximal aerobic and the maximal anaerobic test at the second post-test. The results of this study indicate that intermittent hypobaric training can improve both the aerobic and the anaerobic energy-supply systems.
Several pulse oximeter manufacturers have recently developed instruments that are claimed to be resistant to the effects of patient motion. We performed a laboratory volunteer experiment to compare the performances of several of these instruments, as well as some older models, during combinations of motion and hypoxemia. Twenty oximeters were studied. A motorized table produced different hand motions, and each motion was studied during both room air breathing and hypoxemia. Pulse oximeters on the nonmoving hand were used to provide control measurements for comparison. The Masimo SET((R)) pulse oximeter exhibited the best overall performance, with a performance index (percentage of time in which the SpO(2) reading is within 7% of control value) of 94%. The Agilent Viridia 24C was next, with an 84% index, followed by the Agilent CMS (80%), the Datex-Ohmeda 3740 (80%), and the Nellcor N-395 (69%). For comparison with older oximeter technology, the Criticare 5040 had an index of 28%. Recent technology changes have significantly improved pulse oximeter performance during motion artifact, with the Masimo oximeter leading the way. IMPLICATIONS. New improvements in pulse oximeter technology have resulted in significantly better accuracy and reliability during patient motion. The Masimo pulse oximeter demonstrated the best performance of the 20 instruments tested.
The efficiency of "living high, training low" (LHTL) remains controversial, despite its wide utilization. This study aimed to verify whether maximal and/or submaximal aerobic performance were modified by LHTL and whether these effects persist for 15 days after returning to normoxia. Last, we tried to elucidate whether the mechanisms involved were only related to changes in oxygen-carrying capacity. Eleven elite middle-distance runners were tested before (Pre), at the end (Post1), and 15 days after the end (Post2) of an 18-day LHTL session. Hypoxic group (LHTL, n = 5) spent 14 h/day in hypoxia (6 nights at 2,500 m and 12 nights at 3,000 m), whereas the control group (CON, n = 6) slept in normoxia (1,200 m). Both LHTL and CON trained at 1,200 m. Maximal oxygen uptake and maximal aerobic power were improved at Post1 and Post2 for LHTL only (+7.1 and +3.4% for maximal oxygen uptake, +8.4 and +4.7% for maximal aerobic power, respectively). Similarly oxygen uptake and ventilation at ventilatory threshold increased in LHTL only (+18.1 and +12.2% at Post1, +15.9 and +15.4% at Post2, respectively). Heart rate during a 10-min run at 19.5 km/h decreased for LHTL at Post2 (-4.4%). Despite the stimulation of erythropoiesis in LHTL shown by the 27.4% increase in serum transferrin receptor and the 10.1% increase in total hemoglobin mass, red cell volume was not significantly increased at Post1 (+9.2%, not significant). Therefore, both maximal and submaximal aerobic performance in elite runners were increased by LHTL mainly linked to an improvement in oxygen transport in early return to normoxia and probably to other process at Post2.
This study investigates whether a 6-wk intermittent hypoxia training (IHT), designed to avoid reductions in training loads and intensities, improves the endurance performance capacity of competitive distance runners. Eighteen athletes were randomly assigned to train in normoxia [Nor group; n = 9; maximal oxygen uptake (VO2 max) = 61.5 +/- 1.1 ml x kg(-1) x min(-1)] or intermittently in hypoxia (Hyp group; n = 9; VO2 max = 64.2 +/- 1.2 ml x kg(-1) x min(-1)). Into their usual normoxic training schedule, athletes included two weekly high-intensity (second ventilatory threshold) and moderate-duration (24-40 min) training sessions, performed either in normoxia [inspired O2 fraction (FiO2) = 20.9%] or in normobaric hypoxia (FiO2) = 14.5%). Before and after training, all athletes realized 1) a normoxic and hypoxic incremental test to determine VO2 max and ventilatory thresholds (first and second ventilatory threshold), and 2) an all-out test at the pretraining minimal velocity eliciting VO2 max to determine their time to exhaustion (T(lim)) and the parameters of O2 uptake (VO2) kinetics. Only the Hyp group significantly improved VO2 max (+5% at both FiO2, P < 0.05), without changes in blood O2-carrying capacity. Moreover, T(lim) lengthened in the Hyp group only (+35%, P < 0.001), without significant modifications of VO2 kinetics. Despite similar training load, the Nor group displayed no such improvements, with unchanged VO2 max (+1%, nonsignificant), T(lim) (+10%, nonsignificant), and VO2 kinetics. In addition, T(lim) improvements in the Hyp group were not correlated with concomitant modifications of other parameters, including VO2 max or VO2 kinetics. The present IHT model, involving specific high-intensity and moderate-duration hypoxic sessions, may potentialize the metabolic stimuli of training in already trained athletes and elicit peripheral muscle adaptations, resulting in increased endurance performance capacity.
Acclimatization to moderate high altitude accompanied by training at low altitude (living high-training low) has been shown to improve sea level endurance performance in accomplished, but not elite, runners. Whether elite athletes, who may be closer to the maximal structural and functional adaptive capacity of the respiratory (i.e., oxygen transport from environment to mitochondria) system, may achieve similar performance gains is unclear. To answer this question, we studied 14 elite men and 8 elite women before and after 27 days of living at 2,500 m while performing high-intensity training at 1,250 m. The altitude sojourn began 1 wk after the USA Track and Field National Championships, when the athletes were close to their season's fitness peak. Sea level 3,000-m time trial performance was significantly improved by 1.1% (95% confidence limits 0.3–1.9%). One-third of the athletes achieved personal best times for the distance after the altitude training camp. The improvement in running performance was accompanied by a 3% improvement in maximal oxygen uptake (72.1 ± 1.5 to 74.4 ± 1.5 ml · kg ⁻¹ · min ⁻¹ ). Circulating erythropoietin levels were near double initial sea level values 20 h after ascent (8.5 ± 0.5 to 16.2 ± 1.0 IU/ml). Soluble transferrin receptor levels were significantly elevated on the 19th day at altitude, confirming a stimulation of erythropoiesis (2.1 ± 0.7 to 2.5 ± 0.6 μg/ml). Hb concentration measured at sea level increased 1 g/dl over the course of the camp (13.3 ± 0.2 to 14.3 ± 0.2 g/dl). We conclude that 4 wk of acclimatization to moderate altitude, accompanied by high-intensity training at low altitude, improves sea level endurance performance even in elite runners. Both the mechanism and magnitude of the effect appear similar to that observed in less accomplished runners, even for athletes who may have achieved near maximal oxygen transport capacity for humans.
This study was carried out to investigate the early changes in erythropoietin (EPO) formation in humans in response to hypoxia. Six volunteers were exposed to simulated altitudes of 3,000 and 4,000 m in a decompression chamber for 5.5 h. EPO was measured by radioimmunoassay in serum samples withdrawn every 30 min during altitude exposure and also in two subjects after termination of hypoxia (4,000 m). EPO levels during hypoxia were significantly elevated after 114 and 84 min (3,000 and 4,000 m), rising thereafter continuously for the period investigated. Mean values increased from 16.0 to 22.5 mU/ml (3,000 m) and from 16.7 to 28.0 mU/ml (4,000 m). This rise in EPO levels corresponds to 1.8-fold (3,000 m) and 3.0-fold (4,000 m) increases in the calculated production rate of the hormone. After termination of hypoxia, EPO levels continued to rise for approximately 1.5 h and after 3 h declined exponentially with an average half-life time of 5.2 h.
The effects of respiratory acidosis on glycolysis in the autoperfused canine gastrocnemius-plantaris were studied using anesthetized dogs that were ventilated either with air (n = 30) or with 4% CO2-21% O2-75% N2 (n = 30). The left muscle group was stimulated at 3 Hz for up to 20 min, after which the active and the contralateral resting muscles were removed and frozen in liquid N2. Blood flow, VO2, Vco2, and tension development were unaffected by CO2. Glycogen catabolism was not affected, but lactate release (La) was lower (P less than 0.05) during activity with CO2; and greater fructose 6-phosphate, fructose 6-phosphate/fructose 1,6-diphosphate, and alpha-glycerophosphate/dihydroxyacetone phosphate ratios resulted (P less than 0.05). With respiratory acidosis, muscle lactate tended to accumulate early in contractions, but a net lactate uptake occurred during the last 10 min of contractions. Thus, respiratory acidosis reduced lactate efflux and there was a net uptake late in the contraction period. Glycogen phosphorylase did not appear to be affected by the respiratory acidosis, but there was evidence of inhibition at the phosphofructokinase step as well as a tendency for lactate to accumulate within the muscle. La often occurred in a direction contrary to the muscle-venous lactate concentration difference with either air or CO2 and La also decreased far more rapidly over time than did the arterial-venous H+.
In a previous study of normal subjects exercising at sea level and simulated altitude, ventilation-perfusion (VA/Q) inequality and alveolar-end-capillary O2 diffusion limitation (DIFF) were found to increase on exercise at altitude, but at sea level the changes did not reach statistical significance. This paper reports additional measurements of VA/Q inequality and DIFF (at sea level and altitude) and also of pulmonary arterial pressure. This was to examine the hypothesis that VA/Q inequality is related to increased pulmonary arterial pressure. In a hypobaric chamber, eight normal subjects were exposed to barometric pressures of 752, 523, and 429 Torr (sea level, 10,000 ft, and 15,000 ft) in random order. At each altitude, inert and respiratory gas exchange and hemodynamic variables were studied at rest and during several levels of steady-state bicycle exercise. Multiple inert gas data from the previous and current studies were combined (after demonstrating no statistical difference between them) and showed increasing VA/Q inequality with sea level exercise (P = 0.02). Breathing 100% O2 did not reverse this increase. When O2 consumption exceeded about 2.7 1/min, evidence for DIFF at sea level was present (P = 0.01). VA/Q inequality and DIFF increased with exercise at altitude as found previously and was reversed by 100% O2 breathing. Indexes of VA/Q dispersion correlated well with mean pulmonary arterial pressure and also with minute ventilation. This study confirms the development of both VA/Q mismatch and DIFF in normal subjects during heavy exercise at sea level. However, the mechanism of increased VA/Q mismatch on exercise remains unclear due to the correlation with both ventilatory and circulatory variables and will require further study.
The purpose of the present study was to investigate the blood lactate (LA−) responses to hypoventilation induced by reduced frequency breathing (RFB) during recovery from exercise. Five male subject performed 16 4 min cycling bouts alternating with 16 min rest periods. Exercise intensities were chosen at power outputs corresponding to 30% at 2mMLA−, at 4 mMLA−, and 90% in each subject. Breathing frequency was voluntarily controlled starting 10 s before each 3rd min of exercise and maintained throughout the rest of the exercise period. Four different breathing patterns at each exercise intensity were used: normal breathing (NB), breathing every 4 s, breathing every 8 s, and maximal RFB. Except for the NB trials, subjects held their breath at functional residual capacity during each breathing interval. The concentration difference of LA− between the 3rd min sample and the 4th min sample was defined as the lactate change during exercise (Δ LA−ex), and that between the 4th min sample and the sample at the 3rd min after the end of the exercise as the lactate change during recovery (Δ LA−rec). An ANOVA showed significant (p<0.05) differences in breathing procedures only in ΔLA−rec. ΔLA−rec seemed to increase as compared to NB only at at 4 mMLA− and 90% , while ΔLA−ex remained unchanged as compared to NB in spite of reduced ∵V
A. These results might indicate that RFB inhibited lactate removal from working muscles during exercise.
It is uncertain that exercise with reduced frequency breathing (RFB) results in arterial hypoxemia. This study was designed to investigate whether RFB during exercise creates a true hypoxic condition in arterial blood by examining arterial oxygen saturation (SaO2) directly. Six subjects performed ten 30 s periods of exercise on a Monark bicycle ergometer at a work rate of 210 W alternating with 30 s rest intervals. The breath was controlled to use 1 s each for inspiration and expiration, and two trials with different breathing patterns were used; a continuous breathing (CB) trial and an RFB trial consisting of four seconds of breath-holding at functional residual capacity (FRC). Alveolar oxygen pressure during exercise showed a slight but significant (p less than 0.05) reduction with RFB as compared to CB. However, a marked increase in alveolar-arterial pressure difference for oxygen (A-aDO2) (p less than 0.05) with RFB over CB resulted in a marked (p less than 0.05) reduction in arterial oxygen pressure. Consequently, SaO2 fell as low as 88.8% on average. Additional examination of RFB with breath-holding at total lung capacity showed no increases in A-aDO2 in spite of the same amount of hypoventilation as compared with that at FRC. These results indicate that RFB during exercise can result in arterial hypoxemia if RFB is performed with breath-holding at FRC, this mechanism being closely related to the mechanical responses due to lung volume restriction.
Hypoxic Training, which has been popular in swimming for the past few years, is more correctly called Controlled Breathing Swimming (CBS). This study investigated the acute effects of CBS on blood glucose (GL), lactate (LA), pH, PvCO2, and recovery oxygen uptake. Six male swimmers were studied in two separate swimming sessions using two breathing patterns--free breathing (FB), and 7-stroke breathing (7B). For each session venous blood samples were drawn prior to the swim (Rest), immediately after the swim (IA), and during the 6th minute of recovery (6-R). Analyses for GL, LA, pH, and PvCO2 were carried out, and recovery VO2 (20 minutes) was calculated. Significant increased due to the exercise sessions themselves were found in both GL (p less than 0.05), and LA (p less than 0.05) concentrations. Between the two swim protocols, no significant difference was observed except for a significantly greater % CO2 production after the 7B swim (p less than 0.05). These results indicated that the acute CBS did not induce more glycolytic metabolic activity than did the normal swimming protocol.
Seven normal awake males were studied to define the mechanisms and impact of lung volume on the hypoxemia occurring during apnea. During repeated 30-s voluntary breath holding, these subjects were studied at different lung volumes, during various respiratory maneuvers, and in the sitting and supine body positions. Analysis of expired gases and arterial O2 saturation during these repeated breath holdings yielded the following conclusions. Apnea of 30-s duration at low lung volumes is accompanied by severe arterial O2 desaturation in normal awake subjects. Initial lung volume is the most important determinant of hypoxemia during apnea. The hypoxemia of apnea at most lung volumes can be explained by simple alveolar hypoventilation in a uniform lung. The lung does not behave as a single-compartment model at lung volumes at which dependent airways are susceptible to closure.