Effect of ambient temperature on human skeletal muscle metabolism during fatiguing submaximal exercise
Effect of ambient temperature on human skeletal muscle metabolism during fatiguing submaximal exercise
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DOI：
10.1152/jappl.1999.86.3.902
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发表时间：
1999-03-01
影响因子：
3.3
通讯作者：
Febbraio, MA
中科院分区：
文献类型：
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作者：
Parkin, JM;Carey, MF;Febbraio, MA
为了研究环境温度对疲劳亚极量运动期间代谢的影响，8名男子在三个不同的场合，至少间隔1周，在需要70%峰值肺氧摄取的工作量下骑自行车到精疲力竭。这些试验在3摄氏度（CT）、20摄氏度（NT）和40摄氏度（HT）的环境温度下进行。虽然在运动前没有观察到肌肉或直肠温度的差异，但肌肉和直肠温度都较高疲劳时，HT组较CT组和NT组运动时间延长（P < 0.05），而NT组运动时间又较HT组延长（P < 0.05）（分别为85 +/- 8 vs. 60 +/- 11 vs. 30 +/- 3 min; P < 0.05）。当比较三种试验时，在休息或疲劳时血浆肾上腺素浓度没有差异，但是当HT与NT相比时，这种激素的浓度更高（P < 0.05），运动20分钟后，HT又高于CT（P < 0.05）。当比较三项试验时，静息时肌糖原浓度没有差异，但与NT和CT相比，HT在疲劳时更高，两者没有差异（分别为299 +/- 33与153 +/- 27和116 +/- 28 mmol/kg干重; P < 0.01）。当三个试验比较时，安静时肌内乳酸浓度没有差异，但在疲劳时HT组比CT组更高（P < 0.05）。当比较试验时，在运动前或运动后观察到总肌内腺嘌呤核苷酸池（ATP + ADP + AMP）、磷酸肌酸或肌酸的浓度无差异。尽管在比较三项试验时，运动前后肌内IMP浓度没有统计学差异，但IMP存在运动诱导的增加（P < 0.01）。这些结果表明，在炎热条件下长时间运动期间的疲劳与碳水化合物的可用性无关。此外，与NT相比，CT的耐力增加可能是由于糖原分解率降低。
To examine the effect of ambient temperature on metabolism during fatiguing submaximal exercise, eight men cycled to exhaustion at a workload requiring 70% peak pulmonary oxygen uptake on three separate occasions, at least 1 wk apart. These trials were conducted in ambient temperatures of 3 degrees C (CT), 20 degrees C (NT), and 40 degrees C (HT). Although no differences in muscle or rectal temperature were observed before exercise, both muscle and rectal temperature were higher (P < 0.05) at fatigue in HT compared with CT and NT Exercise time was longer in CT compared with NT, which, in turn, was longer compared with HT (85 +/- 8 vs. 60 +/- 11 vs. 30 +/- 3 min, respectively; P < 0.05). Plasma epinephrine concentration was not different at rest or at the point of fatigue when the three trials were compared, but concentrations of this hormone were higher (P < 0.05) when HT was compared with NT, which in turn was higher (P < 0.05) compared with CT after 20 min of exercise. Muscle glycogen concentration was not different at rest when the three trials were compared but was higher at fatigue in HT compared with NT and CT, which were not different (299 +/- 33 vs. 153 +/- 27 and 116 +/- 28 mmol/kg dry wt, respectively; P < 0.01). Intramuscular lactate concentration was not different at rest when the three trials were compared but was higher (P < 0.05) at fatigue in HT compared with CT. No differences in the concentration of the total intramuscular adenine nucleotide pool (ATP + ADP + AMP), phosphocreatine, or creatine were observed before or after exercise when the trials were compared. Although intramuscular IMP concentrations were not statistically different before or after exercise when the three trials were compared, there was an exercise-induced increase (P < 0.01) in IMP. These results demonstrate that fatigue during prolonged exercise in hot conditions is not related to carbohydrate availability. Furthermore, the increased endurance in CT compared with NT is probably due to a reduced glycogenolytic rate.