急性缺氧對無氧能力的影響

本研究旨在探討在不同氧壓環境下，急性缺氧對人體無氧能力的影響。以43位健康的男性為受試者，分為兩組參與上肢(N=22)和下肢(N=21)在平地和18,000呎（低壓艙）之30秒溫蓋特無氧能力測驗，事先估計個人的最大攝氧量。常氧和低氧的溫蓋特測驗乃探用標準測功計，每隔5秒鐘記錄輸出功率一次，並計算最大值、最小值、平均值、和衰減率。測驗後第30秒測量受試者的血氧飽和度和心跳率，第3分鐘測量血中乳酸濃度。在低壓艙內進行測驗時，皆以至善的氧氣裝備防範缺氧的危險。本研究的結果發現低氧顯著地減少上肢和下肢的最大功率和平白功率，可能導因於ATP的再合成不足，且上肢的最大和平均功率與個體的有氧能力有關；上、下肢運動後的血氧飽和度顯著地降低，似乎是肌肉的極度收縮妨礙了局部的血流；運動後的心跳率居高不下，推測為心臟血管系統的代價性調節，藉以償付非乳酸性氧債；運動後的血中乳酸濃度的升高值以低氧環境較低，可能是缺氧誘導周邊血管擴張的結果。本研究的結果可謹慎地推論於中等高度從事重度勞動作業的情況，顯示均衡的體適能有利於無氧能力的增進。此外，為了避免體力活動損害缺氧時的意識狀態，氧氣裝備的備便乃不可或缺。

關鍵字

急性缺氧；無氧能力；有氧能力；血乳酸濃度

並列摘要

Introduction. The present study was undertaken to investigate the effects of acute hypoxia on human anaerobic capacity. Methods. Forty-three physically healthy males volunteered to participate this study. They were assigned into two groups for testing work power of arms (N=22) and legs (N=21) at sea level and at 18,000 feet. Prior to the experimental protocol, individual maximal oxygen uptake and lean body weight were evaluated. A bicycle ergometer (Monark) was used to conduct the Wingate test under the normoxic and hypoxic conditions. Every 5 seconds work powers were recorded on the computer, which were computed as maximum, minimum, average powers and power drop at the end of test. Blood oxygen saturation and heart rate were measured using oximeter at the 30th sec. right after the maximal exercise. Blood sample was collected at the 3rd minimum of recovery period for analyzing lactate level. Oxygen equipment is available all the time for preventing subjects from hypoxic incidents. Results. A significant decrease in maximum and average powers were found both in arms and legs during acute hypoxia exposure, which might be caused by insufficient ATP re-synthesis and related to aerobic capacity. Blood oxygen saturation was seen much lower both in arm cranking and leg pedaling in the early phase of post-exercise. To the contrast, heart rate was seen much higher in the same period. This acceleration might be the compensatory mechanism paying for alactic oxygen debt. A lower lactate level also showed after the exhausted arm exercise in hypoxic condition, which was possibly caused by vasodilation. Conclusion. It is suggested that those who perform heavy work in the moderate altitude should be equipped with oxygen apparatus and aware of the hypoxic syndromes exacerbated by physical activity. Besides, physical fitness will improve the anaerobic capacity to some extent.

並列關鍵字

acute hypoxia ； anaerobic capacity ； aerobic capacity ； blood lactate

國際替代計量

急性缺氧對無氧能力的影響

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