Effect of acute severe hypoxia on peripheral fatigue and endurance capacity in healthy humans
Effect of acute severe hypoxia on peripheral fatigue and endurance capacity in healthy humans
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DOI：
10.1152/ajpregu.00269.2006
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发表时间：
2007-01-01
影响因子：
2.8
通讯作者：
Dempsey, Jerome A.
中科院分区：
文献类型：
--
作者：
Romer, Lee M.;Haverkamp, Hans C.;Dempsey, Jerome A.
我们假设，严重缺氧限制运动表现通过减少肢体运动肌肉的收缩。9名男性受试者[平均+/- SE最大摄氧量（VO 2 max）= 56.5 +/- 2.7 ml中心点kg（-1）中心点min（-1）]在>= 90%Vo（2）（max）时循环至常氧[NORM-EXH;吸入的O-2分数（FIO 2）= 0.21，动脉O-2饱和度（Sp（O2））= 93 +/- 1%]和缺氧（HYPOX-EXH; FIO 2 = 0.13，Sp（O2）= 76 +/- 1%）。受试者还在常氧条件下运动，运动时间与缺氧条件下相同（NORM-CTRL; Sp（O2）= 96 +/- 1%）。股四头肌抽搐力，在股神经（10-100 Hz）的超最大的单一（非增强和增强1 Hz）和成对的磁刺激，进行了评估前，并在2.5，35，和70分钟后运动。缺氧加剧了运动诱导的外周疲劳，如HYPOX-EXH与NORM-CTRL相比增强的抽搐力的更大降低所证明的（-39 +/-4vs.-24 +/-3%，P < 0.01）。HYPOX-EXH组与NORM-EXH组相比，至力竭时间缩短了三分之二以上（4.2 +/- 0.5 vs. 13.4 +/- 0.8 min，P < 0.01）;然而，HYPOX-EXH组与NORM-EXH组外周疲劳无差异（-34 +/- 4 vs. -39 +/-4%，P < 0.05）。血液乳酸浓度和肢体不适的感觉在整个HYPOX-EXH与NORM-CTRL中更高，但在HYPOX-EXH与NORM-EXH的运动结束时没有差异。我们的结论是，严重缺氧加剧外周疲劳的肢体运动肌肉，这种影响可能有助于，在一定程度上，提前终止运动。
We hypothesized that severe hypoxia limits exercise performance via decreased contractility of limb locomotor muscles. Nine male subjects [mean +/- SE maximum O-2 uptake (VO2 max) = 56.5 +/- 2.7 ml center dot kg(-1)center dot min(-1)] cycled at >= 90% Vo(2) (max) to exhaustion in normoxia [NORM-EXH; inspired O-2 fraction (FIO2) = 0.21, arterial O-2 saturation (Sp(O2)) = 93 +/- 1%] and hypoxia (HYPOX-EXH; FIO2 = 0.13, Sp(O2) = 76 +/- 1%). The subjects also exercised in normoxia for a time equal to that achieved in hypoxia (NORM-CTRL; Sp(O2) = 96 +/- 1%). Quadriceps twitch force, in response to supramaximal single (nonpotentiated and potentiated 1 Hz) and paired magnetic stimuli of the femoral nerve (10-100 Hz), was assessed pre- and at 2.5, 35, and 70 min postexercise. Hypoxia exacerbated exercise-induced peripheral fatigue, as evidenced by a greater decrease in potentiated twitch force in HYPOX-EXH vs. NORM-CTRL (-39 +/- 4 vs. -24 +/- 3%, P < 0.01). Time to exhaustion was reduced by more than two-thirds in HYPOX-EXH vs. NORM-EXH (4.2 +/- 0.5 vs. 13.4 +/- 0.8 min, P < 0.01); however, peripheral fatigue was not different in HYPOX-EXH vs. NORM-EXH (-34 +/- 4 vs. -39 +/- 4%, P < 0.05). Blood lactate concentration and perceptions of limb discomfort were higher throughout HYPOX-EXH vs. NORM-CTRL but were not different at end-exercise in HYPOX-EXH vs. NORM-EXH. We conclude that severe hypoxia exacerbates peripheral fatigue of limb locomotor muscles and that this effect may contribute, in part, to the early termination of exercise.