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To test the hypothesis that heightened sympathetic outflow precedes and predicts the magnitude of the growth hormone (GH) response to acute exercise (Ex), we studied 10 men [age 26.1 +/- 1.7 (SE) yr] six times in randomly assigned order (control and 5 Ex intensities). During exercise, subjects exercised for 30 min (0900-0930) on each occasion at a...
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Objective: To compare anaerobic threshold (AT) intensities determined from blood lactate, blood glucose and ventilatory responses among sedentary (SD) and physically active (AD) type-2 diabetics and active non-diabetics (AND), and to correlate metabolic, hemodynamic and body composition variables with the AT. Method: The SD (n= 9, 56.7 +/- 11.9 yea...
The effects of coca chewing on prolonged submaximal exercise responses were investigated in chronic coca chewers and compared with a group of nonchewers. At rest, coca chewing during a 1-h period was followed by a significant increase in blood glucose, free fatty acid, and norepinephrine concentrations and a significant reduction in insulin plasma...
Identification of the anaerobic threshold in sedentary and physically active individuals with type 2 diabetes Objective: To compare anaerobic threshold (AT) intensities determined from blood lactate, blood glucose and ventilatory responses among sedentary (SD) and physically active (AD) type-2 diabetics and active non-diabetics (AND), and to correl...
Citations
... This hypothesis is reinforced by the study published by Weltman and collaborators. According to them, exercise-induced growth hormone release is dependent on sympathetic activation (30). Nevertheless, the activation of the muscle metaboreflex and the attenuation of the baroreflex response induced by physical activity explain not only the activation of the hypothalamic-hypophyseal-thyroid axis but also the significant increase in T3 levels. ...
International Journal of Exercise Science 15(2): 760-770, 2022. The present study aimed to compare the exercise order of an acute bout of resistance exercise (RT) on acute thyroid hormonal responses. Eight (n = 8) healthy men were randomly separated into two experimental groups: A) the order from multi-to single-joint exercises (MJ-SJ) and B) the order from single-to multijoint exercises (SJ-MJ). For all exercises in both orders, the subjects were submitted to 3 sets of 10 repetitions, with rest intervals of 2 minutes between sets and 3 minutes between exercises. Blood samples were collected at rest and 0, 15, 30, 60 and 120 min after the end of the exercise session. In thyroid-stimulating hormone (TSH), differences between groups (MJ-SJ < SJ-MJ) were observed within 15 minutes after the session. In 3,5,3'-triiodothyronine (T3), differences between groups were observed between 30 (MJ-SJ > SJ-MJ) and 120 minutes (MJ-SJ < SJ-MJ) after the session. In 3,5,3',5'-tetraiodothyronine (T4), differences between groups (MJ-SJ > SJ-MJ) were observed within 15 minutes after the RT session. The order of RT exercises significantly changes the hormonal responses of TSH, T3 and T4. In addition, the exercise order should be chosen according to the individual's objectives.
... The difference might be at least partially explained by altered endocrinological responses. After WBVE, GH levels were elevated compared with rest, and this response was apparently consistent with that observed after conventional exercise [20]. However, a recent study demonstrated that GH levels were higher after WBVE (i.e., exercise using WBV) than after exercise without WBV, suggesting that the stimulation of WBV per se would additionally increase GH levels [21]. ...
... Catecholamine levels are another important factor increasing plasma glucose levels. Previous studies demonstrated that noradrenaline rather than adrenaline levels were predominantly increased after conventional exercise [20]. Conversely, in the current study, adrenaline levels were significantly elevated 10 min after WBVE, whereas noradrenaline levels were not. ...
Purpose
Exercise on a whole body vibration (WBV) platform, namely WBV exercise (WBVE), has long-term beneficial effects on glucose metabolism, similarly to conventional moderate-intensity exercise. Conventional moderate-intensity exercise reduces post-load plasma glucose levels at the acute phase. This study aimed to reveal acute effects of WBVE on post-load glucose metabolism.
Methods
This randomized crossover trial enrolled 18 healthy men. They completed the following three interventions in a random order: (1) a 2-hour 75-g oral glucose tolerance test (OGTT) without WBVE (OGTT-alone), (2) 20-minute WBVE before an OGTT (WBVE → OGTT), and (3) 20-minute WBVE during an OGTT (OGTT → WBVE). Post-load glucose metabolism in the WBVE → OGTT and OGTT → WBVE interventions were compared with that in the OGTT-alone intervention.
Results
Plasma glucose levels in the WBVE → OGTT and OGTT → WBVE interventions were not significantly different from those in the OGTT-alone intervention at any time point except 15 min, wherein the WBVE → OGTT intervention had higher glucose levels (111 [interquartile range, 102–122] mg/dL vs 122 [111–134] mg/dL, P = 0.026). Higher plasma glucagon levels were observed at 0 min in the WBVE → OGTT intervention and at 60 min in the OGTT → WBVE intervention (P = 0.010 and 0.015). Cortisol, Growth hormone, and adrenaline levels were significantly increased after WBVE, whereas noradrenaline levels were not. Serum insulin levels in the WBVE → OGTT intervention were significantly higher than those in the OGTT-alone intervention at 0 min (P = 0.008).
Conclusions
WBVE did not decrease post-load plasma glucose levels at the acute phase. Acute effects of WBVE on post-load glucose metabolism would not be identical to those of conventional exercise.
The unique trial number and the name of the registry: UMIN000036520, www.umin.ac.jp, date of registration, June 12, 2019.
... However, while the plasma adrenaline and growth hormone concentrations were acutely elevated following HWI in the present study, it is important to point out that the halflife of these hormones is rather short. Adrenaline concentrations return to baseline within~30 min of recovery from exercise (Weltman et al. 2000) or HWI (Jimenez et al. 2007;Whitham et al. 2007;Laing et al. 2008); growth hormone concentrations return to baseline withiñ 60-90 min following exercise (Weltman et al. 2000) or HWI (Jurcovicov a et al. 1980). As the differences in glucose concentration between conditions in the present study were found in the second half of the OGTT (120-180 min post-HWI), the influence of catecholamines and growth hormone on glycemic control is likely to be indirect, by inducing processes with longer lasting effects. ...
... However, while the plasma adrenaline and growth hormone concentrations were acutely elevated following HWI in the present study, it is important to point out that the halflife of these hormones is rather short. Adrenaline concentrations return to baseline within~30 min of recovery from exercise (Weltman et al. 2000) or HWI (Jimenez et al. 2007;Whitham et al. 2007;Laing et al. 2008); growth hormone concentrations return to baseline withiñ 60-90 min following exercise (Weltman et al. 2000) or HWI (Jurcovicov a et al. 1980). As the differences in glucose concentration between conditions in the present study were found in the second half of the OGTT (120-180 min post-HWI), the influence of catecholamines and growth hormone on glycemic control is likely to be indirect, by inducing processes with longer lasting effects. ...
Chronic hot water immersion (HWI) confers health benefits, including a reduction in fasting blood glucose concentration. Here we investigate acute glycemic control immediately after HWI. Ten participants (age: 25 ± 6 years, body mass: 84 ± 14 kg, height 1.85 ± 0.09 m) were immersed in water (39°C) to the neck (HWI) or sat at room temperature (CON) for 60 min. One hour afterward they underwent an oral glucose tolerance test (OGTT), with blood collected before and after HWI/CON and during the 2 h OGTT. Glucose incremental area under the curve (iAUC) during the OGTT was higher for HWI (HWI 233 ± 88, CON 156 ± 79 mmol·L−1·2 h, P = 0.02). Insulin iAUC did not differ between conditions (HWI 4309 ± 3660, CON 3893 ± 3031 mU·L−1·2 h, P = 0.32). Core temperature increased to 38.6 ± 0.2°C during HWI, but was similar between trials during the OGTT (HWI 37.0 ± 0.2, CON 36.9 ± 0.4°C, P = 0.34). Directly following HWI, plasma average adrenaline and growth hormone concentrations increased 2.7 and 10.7‐fold, respectively (P < 0.001). Plasma glucagon‐like peptide‐1, peptide YY, and acylated ghrelin concentrations were not different between trials during the OGTT (P > 0.11). In conclusion, HWI increased postprandial glucose concentration to an OGTT, which was accompanied by acute elevations of stress hormones following HWI. The altered glycemic control appears to be unrelated to changes in gut hormones during the OGTT. We report higher postprandial blood glucose concentrations after 60 min of hot water immersion (HWI) at 39°C when compared with resting control. The postprandial gut hormone and hunger responses do not appear to be related to the differential glucose response as they were unaffected by HWI.
... The possible higher catecholamine secretion resulting from the greater sympathetic activation in response to the higher exercise intensity in the SIT might have driven lipolysis from visceral fat storage via β 3adrenoceptors (Zouhal et al., 2013;Maillard et al., 2018) in a greater extent in comparison to that of HIIT. Moreover, the greater central motor activity (Kjaer et al., 1996) in accomplishing the maximum power output in a repeated, transient "startstop" manner in SIT, along with the associated repeating stimulations in various signaling pathways including adrenergic pathway (Weltman et al., 2000;Gibala and Hawley, 2017) might have potentiated the exercise-induced growth hormone release, facilitating a reduction of visceral fat (Freda et al., 2008). The elevated exercise-induced lipolytic hormones in plasma which have been shown to sustain for more than an hour after a brief session of high-intensity interval exercise, might have also contributed to the specific fat loss in association to the postexercise fat metabolism (Williams et al., 2013;Sasaki et al., 2014). ...
Introduction: High-intensity interval training (HIIT) is an emerging lifestyle intervention strategy for controlling obesity. HIIT consisted of brief all-out supramaximal sprint intervals was termed as sprint interval training (SIT). This study was designed to examine the time-efficient characteristics of SIT in reducing abdominal visceral fat.
Methods: A randomized controlled trial was conducted to compare the specific adaptations of SIT (80 × 6 s all-out cycle sprints interspersed with 9 s passive recovery) with those resulting from a HIIT regimen with training volume relatively higher (repeated 4 min bouts of cycling at 90% V˙O2max alternated with 3 min rest, until the work of 400KJ was achieved), and with those of nonexercising control counterparts (CON). Forty-six obese young women (body fat percentage ≥30) received either SIT (n = 16), HIIT (n = 16), or no training (n = 14), 3–4 sessions per week, for 12 weeks. The abdominal visceral fat area (AVFA) and abdominal subcutaneous fat area (ASFA) of the participants were measured through computed tomography scans pre-intervention and post-intervention. Total fat mass and the fat mass of the android, gynoid, and trunk regions were assessed through dual-energy X-ray absorptiometry.
Results: Following the intervention, abdominal visceral and subcutaneous fat were reduced markedly (p < 0.05). The reduction in AVFA (−6.31, −9.7 cm²) was not different between SIT and HIIT (p > 0.05), while the reduction in ASFA (−17.4, −40.7 cm²) in SIT was less than that in HIIT (p < 0.05). Less reduction in the fat mass of the trunk (−1.2, −2.0 kg) region was also found in SIT, while the reductions in fat percentage (−1.9%, −2.0%), total fat mass (−2.0, −2.8 kg), and fat mass of the android (−0.2, −0.2 kg), and gynoid (−0.4, −0.3 kg) regions did not differ between the two regimes (p > 0.05). In contrast, the increase in V˙O2max was significant greater following the SIT than HIIT (p < 0.01). No variable changed in CON.
Conclusion: Such findings suggest that the lower training load and exercise time commitments of the SIT regime could optimize the time-efficiency advantage of the traditional HIIT, facilitating the abdominal visceral fat reduction in obese young women.
... The effects of leptin modulating satiety are directly related to NO production. A decrease in food consumption induced by leptin infusion was mitigated by L-arginine infusion in chicken 23 . Ventricular intra-brain infusions of leptin promoted an expected suppression of food intake and reduction in nNOS activity; both effects are antagonized by L-arginine infusions 1 . ...
... In addition, an increase in the absolute weight was observed in animals treated with L-arginine orally and chronically, which correlates with increased water intake that fits with ratios between total body mass and water replacement needs. Previous studies showed that L-arginine may act on two fronts in these events, one goes through an amplified signal for the production of GH via stimulus in the anterior hypophysis 25 , and the other through an alternate route in the process of creatine formation and consequently resulting in a sarcoplasmic hypertrophy from increased fluid retention 26 and increased contractile filaments 23 . ...
Objective:
This study investigated the chronic (oral) and acute (hypothalamic infusion) effects of L-arginine supplementation on feed intake, body composition, and behavioral changes in rats.
Methods:
Twenty rats were divided into two groups treated orally for 60 days; one group received L-arginine (1 g/kg body weight) and one group received saline (1 mL/NaCl 0.9%). Daily consumption of water and food were evaluated, and weight monitored. After the oral treatment, the rats underwent stereotactic biopsy and a group was injected with 2 µL of L-arginine (0.5 mM) and another received an injection of saline (0.9% NaCl), in the hypothalamic route, through micro infusion. Immediately after micro infusion, the animal behavior was evaluated through tests in the open field. Food and water consumption were evaluated at 12 and 24 hours after the micro infusion. Daily water consumption and weight gain evolution were evaluated. At the end of treatments, rats were euthanized and blood was collected for glucose, glycerol, and cholesterol evaluation, and histological analysis of vital organs.
Results:
Oral supplementation with L-arginine increased water intake (11%, p<0.05) and promoted weight gain (3%, p<0.05). However, hypothalamic infusion promoted a significant increase in chow intake (30%, p<0.05) after 24 hours of L-arginine administration.
Conclusion:
Chronic oral treatment with L-arginine was not effective on appetite modulation; however, an effect was observed when L-arginine was administered directly into the hypothalamus, suggesting a central regulation on appetite through nNOS sensitization. Chronic use of L-arginine did not cause substantial changes in anthropometric, biochemical, behavioral, or histological variables.
... Sympathetic activity may be an important mediator of the GH response to acute exercise, possibly via activation of central α 2 -adrenergic neurons. [1] Weltman et al. [129] demonstrated that peak plasma adrenaline and nor-adrenaline concentrations preceded the peak in serum GH concentrations. Multiple regression analysis revealed that prior increases in noradrenaline with resulting significant increments in GH could not be explained by adrenaline alone. ...
... Multiple regression analysis revealed that prior increases in noradrenaline with resulting significant increments in GH could not be explained by adrenaline alone. [129] In creases in serum GH and catecholamines with exercise are also similarly affected by exercise training. [115] Additionally, ghrelin, cholinergic and opioid pathways may also be involved. ...
Objective: The aim of this comparative experimental study designed is analyze the possible changes in GH serum and lactate during the performance of resistance exercise-induced ischemia in young athletes. A possible outcome will be to promote greater strength gains and muscle hypertrophy during the training protocol.
Design: This survey was conducted with 18 male football players 18 years of age. The athletes were divided into two groups; one group was subjected only to quadriceps exercises; the other group was subjected to quadriceps exercises associated with vascular occlusion. Levels of lactate and GH were observed before and after resistance exercise.
Results: Comparing intergroup data, there were no statistically significant results. However, when comparing data within the groups, there was an increase in Group 2 obtained for both the lactate threshold and GH. Group 1 showed an increase in the lactate threshold, but a decrease in GH.
Conclusions: This new method of resistance training should be analyzed, and further experiments are needed to optimize the protocol to reach optimum high intensity resistance training in young athletes.
... The actions of GH and testosterone are enhanced by catecholamines, which reflect the acute demands of exercise, and influence force production, muscle contraction rate and energy availability [65][66][67]. Research has reported low-intensity resistance exercise with BFR to increase norepinephrine secretion, in concert with GH and lactate levels, more than without BFR [8,18]. However, the relationship between GH and norepinephrine levels was not significant [18]. ...
It is generally believed that optimal hypertrophic and strength gains are induced through moderate- or high-intensity resistance training, equivalent to at least 60 % of an individual's 1-repetition maximum (1RM). However, recent evidence suggests that similar adaptations are facilitated when low-intensity resistance exercise (~20-50 % 1RM) is combined with blood flow restriction (BFR) to the working muscles. Although the mechanisms underpinning these responses are not yet firmly established, it appears that localized hypoxia created by BFR may provide an anabolic stimulus by enhancing the metabolic and endocrine response, and increase cellular swelling and signalling function following resistance exercise. Moreover, BFR has also been demonstrated to increase type II muscle fibre recruitment during exercise. However, inappropriate implementation of BFR can result in detrimental effects, including petechial haemorrhage and dizziness. Furthermore, as BFR is limited to the limbs, the muscles of the trunk are unable to be trained under localized hypoxia. More recently, the use of systemic hypoxia via hypoxic chambers and devices has been investigated as a novel way to stimulate similar physiological responses to resistance training as BFR techniques. While little evidence is available, reports indicate that beneficial adaptations, similar to those induced by BFR, are possible using these methods. The use of systemic hypoxia allows large groups to train concurrently within a hypoxic chamber using multi-joint exercises. However, further scientific research is required to fully understand the mechanisms that cause augmented muscular changes during resistance exercise with a localized or systemic hypoxic stimulus.
... En respuesta al ejercicio se ha observado un incremento de los niveles de catecolaminas a medida que aumenta la intensidad de ejercicio (Weltman et al., 2000), describiéndose incluso un denominado umbral de catecolaminas (Schwarz y Kinderman, 1990;Weltman et al., 1994) que coincide con la denominada transición aeróbicaanaeróbica (Schneider, McLellan y Gass, 2000) y que tendría por objeto adaptar la función cardíaca y metabólica al ejercicio (Christensen y Galbo, 1983). Si realizamos una extrapolación del comportamiento de las catecolaminas al ejercicio, podríamos pensar que el incremento de éstas frente a condiciones de hipoxia, serían las responsables de explicar el incremento de la frecuencia cardíaca y de la tensión arterial, aún en condiciones de reposo. ...
Entre las distintas estrategias empleadas con objeto de mejorar el rendimiento deportivo se ha empleado tradicionalmente las concentraciones de entrenamiento en altura. En la actualidad dicha práctica se ha hecho más común, al posibilitarse la realización de exposiciones a estímulos de hipoxia intermitente, gracias a la utilización de distintas tecnologías como las cámaras hipobáricas. Algunos estudios han intentado comprobar el efecto de distintos protocolos de exposición a ambientes hipóxicos sobre el rendimiento deportivo y sobre las variables relacionadas con el sistema sanguíneo. Sin embargo, con frecuencia, no se tiene en cuenta que, como respuesta a la hipoxia, el cuerpo reacciona con una serie de respuestas y adaptaciones a nivel multisistémico. Además, el descubrimiento de la hepcidina ha hecho comprender mejor el conocimiento existente acerca del metabolismo del hierro. Dado que condiciones de hipoxia podrían alterar la síntesis de hepcidina, el objetivo del presente estudio de revisión bibliográfica ha sido doble: I) comprobar las distintas respuestas y adaptaciones a nivel multisistémico a condiciones de hipoxia; II) integrar la hepcidina como posible variable que interviene en las respuestas que tienen lugar en relación al metabolismo del hierro.
... Stress hormones are released into the circulation as the intensity of exercise increases. Plasma adrenaline, noradrenaline and growth hormone concentrations rise in an exponential manner with increasing intensity (93)(94)(95). By contrast, plasma cortisol concentration only increases above exercise intensities of >60% V . ...
Interaction between the endocrine and immune system is necessary to regulate our health. However, under some conditions, stress hormones can overstimulate or suppress the immune system, resulting in harmful consequences (1). Stress is often considered negative, yet it is an intrinsic part of everyday life. Stress is not clearly defined; it is context-specific and depends on the nature of factors that challenge our body. Internal stimuli will elicit different stress reactions compared with external stimuli (1). Similarly, some stressors will induce responses that may benefit survival, whereas others will cause disturbances that may endanger our health. Stress also depends on how our bodies perceive and respond to stressful stimuli (1).
... Similar to lactate, catecholamines also show an inflection point during incremental exercise. Such threshold in the concentration of catecholamines is highly correlated with the accumulation of blood lactate (bLac) and occurs at equivalent work rates (Weltman et al. 2000). Traditionally, this threshold has been referred to as the lactate threshold and may be defined as an abrupt transition, from a slowly increasing phase to a rapidly accelerating phase in the accumulation of bLac during incremental exercise (Svedahl and MacIntosh 2003). ...
This study examined intra-individual variations in salivary lactate (sLac), alpha-amylase (sAA) and chromogranin A (sCgA) with reference to the accumulation of blood lactate (bLac) during incremental maximal exercise in swimmers. Samples of blood and saliva were collected simultaneously from 12 male professional athletes during an incremental test that consisted of eight series of 100 m in front crawl with increasing velocity (0.03 m s(-1) each) and 70-s intervals. The concentration of blood and salivary lactate was determined by an electro-enzymatic assay, whereas sAA and CgA were analysed by Western blotting. Inflection points in the concentration of bLAc, sLac, sAA and CgA were found in all subjects. The accumulation of lactate in saliva followed the same pattern observed in blood with a high correlation between the two (r = 0.91). Similar results were observed between the dynamics of sAA (r = 0.81) and sCgA (r = 0.82) in relation to bLac. These findings support the usefulness of saliva for the determination of the lactate threshold and provide the first demonstration of sCgA as a novel marker of exercise intensity in well-trained men.
