Arterial haemoglobin oxygen saturation is affected by F1O2 at submaximal running velocities in elite athletes
ABSTRACT 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 (F1O2). Six highly trained endurance athletes (5 women and 1 man, aged 25 ± 4 yr, VO2max 71.3 ± 5.0 ml · kg−1· min−1) ran 4 × 4 min on a treadmill in normoxia (F1O2 0.209), hypoxia (F1O2 0.155) and hyperoxia (F1O2 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 Sp2% 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 F1O2, 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 F1O2-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.
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ABSTRACT: The benefits of living and training at high altitude (HiHi) for an improved sea-level performance have been questioned because controlled studies have shown contradictory results. HiHi increases red blood cell mass (RCM), but training in hypoxia may be either an inadequate (low-intensity) or even harmful (to heart, muscle, and brain) stimulus. Recent studies indicate that the best approach to attain the benefits and overcome the problems of altitude training is to sleep at a natural or simulated moderate altitude and train at low altitude or sea level (HiLo). HiLo training increases RCM, as well as sea-level VO(2max) and performance (at least in responders), if certain prerequisites are fulfilled. The minimum dose seems to be more than 12 hours per day for over 3 weeks at an altitude or simulated altitude of 2100 to 2500 m. The effects of exposure to hypoxia seem to persist for a short period during the subsequent training or racing in normoxia.Current Sports Medicine Reports 09/2003; 2(4):233-8. · 1.51 Impact Factor
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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).Respiratory Physiology & Neurobiology 08/2007; 158(1):75-82. · 2.05 Impact Factor
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ABSTRACT: This study investigated the effects of training with voluntary hypoventilation (VH) at low pulmonary volumes. Two groups of moderately trained runners, one using hypoventilation (HYPO, n=7) and one control group (CONT, n=8), were constituted. The training consisted in performing 12 sessions of 55 min within 4 weeks. In each session, HYPO ran 24 min at 70% of maximal O(2) consumption ( [V(02max)) with a breath holding at functional residual capacity whereas CONT breathed normally. A V(02max) and a time to exhaustion test (TE) were performed before (PRE) and after (POST) the training period. There was no change in V(O2max), lactate threshold or TE in both groups at POST vs. PRE. At maximal exercise, blood lactate concentration was lower in CONT after the training period and remained unchanged in HYPO. At 90% of maximal heart rate, in HYPO only, both pH (7.36+/-0.04 vs. 7.33+/-0.06; p<0.05) and bicarbonate concentration (20.4+/-2.9 mmolL(-1) vs. 19.4+/-3.5; p<0.05) were higher at POST vs. PRE. The results of this study demonstrate that VH training did not improve endurance performance but could modify the glycolytic metabolism. The reduced exercise-induced blood acidosis in HYPO could be due to an improvement in muscle buffer capacity. This phenomenon may have a significant positive impact on anaerobic performance.Respiratory Physiology & Neurobiology 03/2008; 160(2):123-30. · 2.05 Impact Factor