Intermittent hypoxia does not increase exercise ventilation at simulated moderate altitude
Intermittent hypoxia does not increase exercise ventilation at simulated moderate altitude
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DOI：
10.1055/s-2006-955895
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发表时间：
2007-06-01
影响因子：
2.5
通讯作者：
Miyamura, M.
中科院分区：
文献类型：
--
作者：
Katayama, K.;Sato, K.;Miyamura, M.
最近的人体研究表明，静息低氧缓解反应（HVR），这是一个指标的缓解化学敏感性缺氧，增加后，短期间歇性缺氧休息。此外，在模拟高海拔运动期间，间歇性低氧导致通气量和动脉血氧饱和度（SaO（2））增加，通气量增加与HVR的变化相关。然而，还没有研究已经澄清的化学敏感性和运动通气在中度高原间歇性缺氧后，在休息状态下之间的关系。本研究的目的，因此，是阐明是否间歇性低氧在休息时引起的通气量增加，在中度海拔运动，伴随着低氧化疗敏感性的增加。18名受过训练的男性跑步者被分为三组，即，第一低氧组（H-1组，n = 6）、第二低氧组（H-2组，n = 6）和对照组（C组，n = 6）。低氧帐篷系统用于间歇性低氧，并且帐篷中的氧水平对于H-1组保持在15.5 +/-0.1%（模拟海拔2500），对于H-2组保持在12.3 +/-0.2%（模拟海拔4300）。H-1组和H-2组每天在低氧帐篷中呆1h，持续1周。在间歇性缺氧前后进行呼吸15.5 +/-0.01%O-2（模拟海拔2500 m）的最大和次最大运动试验。静息HVR也确定在每一个主题使用渐进式等二氧化碳缺氧方法。H-2组HVR在间歇性缺氧后显著增加（p < 0.05），而H-1组和C组HVR无明显变化。在模拟海拔2500米的最大和次最大运动期间，两组在每天1小时持续1周的间歇性低氧后，通气量和SaO（2）均未发生变化。这些结果表明，短期间歇性低氧后静息低氧化学敏感性的变化不影响在中度高原运动期间的通气。
Recent human studies have shown that resting hypoxic ventilatory response (HVR), which is an index of ventilatory chemosensitivity to hypoxia, increased after short-term intermittent hypoxia at rest. In addition, intermittent hypoxia leads to increases in ventilation and arterial oxygen saturation (SaO(2)) during exercise at simulated high altitude, with the increase in ventilation correlated to the change in HVR. However, no study has been made to clarify the relationship between ventilatory chemosensitivity and the exercise ventilation at moderate altitude following intermittent hypoxia during a resting state. The purpose of the present study, therefore, was to elucidate whether intermittent hypoxia at rest induces the increase in ventilation during exercise at moderate altitude that is accompanied by an increase in hypoxic chemosensitivity. Eighteen trained male runners were assigned to three groups, i.e., the first hypoxic group (H-1 group, n = 6), the second hypoxic group (H-2 group, n = 6), and a control group (C group, n = 6). The hypoxic tent system was utilized for intermittent hypoxia, and the oxygen levels in the tent were maintained at 15.5 +/- 0.1 % (simulated 2500 in altitude) for the H-1 group and 12.3 +/- 0.2 % (simulated 4300 in altitude) for the H-2 group. The H-1 and H-2 groups spent 1 hour per day in the hypoxic tent for 1 week. Maximal and submaximal exercise tests while breathing 15.5 +/- 0.01 % O-2 (simulated altitude of 2500 m) were performed before and after intermittent hypoxia. Resting HVR was also determined in each subject using a progressive isocapnic hypoxic method. In the H-2 group, HVR increased significantly (p < 0.05) following intermittent hypoxia, while no change in HVR was found in the H-1 or C group. Neither ventilation nor SaO(2) during maximal and submaximal exercise at a simulated altitude of 2500 m were changed in either group after 1 hour per day for 1 week of intermittent hypoxia. These results suggest that the change in resting hypoxic chemosensitivity after short-term intermittent hypoxia does not affect ventilation during exercise at moderate altitude.