期刊
JOURNAL OF APPLIED PHYSIOLOGY
卷 97, 期 3, 页码 1077-1081出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/japplphysiol.01321.2003
关键词
oxidative capacity; mitochondria; exercise; intracellular oxygenation; 31-phosphorous-magnetic resonance spectroscopy
资金
- NHLBI NIH HHS [HL-17731] Funding Source: Medline
Previously, it was demonstrated in exercise-trained humans that phosphocreatine (PCr) recovery is significantly altered by fraction of inspired O-2 ((FI)(), suggesting that in this population under normoxic conditions, O)(O2)(2) (availability limits maximal oxidative rate. Haseler LJ, Hogan ML, and Richardson RS. J Appl Physiol 86: 2013 - 2018, 1999. To further elucidate these population-specific limitations to metabolic rate, we used 31P-magnetic resonance spectroscopy to study the exercising human gastrocnemius muscle under conditions of varied FIO)(2) (in sedentary subjects. To test the hypothesis that PCr recovery from submaximal exercise in sedentary subjects is not limited by O)(2) (availability, but rather by their mitochondrial capacity, six sedentary subjects performed three bouts of 6-min steady-state submaximal plantar flexion exercise followed by 5 min of recovery while breathing three different FI)(O2) ((0.10, 0.21, and 1.00). PCr recovery time constants were significantly longer in hypoxia (47.0 +/- 3.2 s), but there was no difference between hyperoxia (31.8 +/- 1.9 s) and normoxia (30.0 +/- 2.1 s) (mean +/- SE). End-exercise pH was not significantly different across treatments. These results suggest that the maximal muscle oxidative rate of these sedentary subjects, unlike their exercise-trained counterparts, is limited by mitochondrial capacity and not O)(2) (availability in normoxia. Additionally, the significant elongation of PCr recovery in these subjects in hypoxia illustrates the reliance on O)(2) (supply at the other end of the O)(2) availability spectrum in both sedentary and active populations.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据