短期「高住低訓」訓練方式對單次運動後人體骨骼肌肉肝醣合成之影響

The influence of short-term normoxic exercise training and recovery in hypoxic condition on glycogen synthesis in exercised human skeletal muscle

目的：探討短期「高住低訓」的訓練方式，是否能提高單次運動後人體肌肉肝醣合成能力。方法：八名健康且規律運動男性進行交叉實驗設計，排空期為二十一天。受試者隨機接受每天一小時70％最大攝氧量（V.O2max）訓練且常壓常氧環境睡眠共七天（控制實驗），或每天一小時運動訓練（70％V.O2max）且常壓低氧環境睡眠十小時（低氧實驗）共七天。兩種實驗皆在第八天進行單次一小時70％V.O2max腳踏車運動，隨後採集肌肉樣本，再給予補充高碳水化合物飲食，後續第四小時執行第二次肌肉採樣。血液樣本於單次運動前後、運動後四小時期間每三十分鐘採血。研究數據以重複量數雙因子變異數分析。結果：低氧實驗在運動後肌肉肝醣濃度顯著高於控制實驗（p＜.05）；低氧實驗的游離脂肪酸與甘油濃度在運動前、後與運動後三十分鐘顯著低於控制實驗（p＜.05）；兩種實驗的血漿葡萄糖、血漿葡萄糖曲線下面積、胰島素、胰島素曲線下面積、皮質醇濃度在不同時間點皆未達顯著差異。結論：短期高住低訓可能加速運動恢復初期的人體骨骼肌肉肝醣合成速率，提高人體對醣類的利用與儲存，具肝醣超補的作用。To investigate whether short-term normoxic exercise training and recovery in hypoxic condition could enhance the glycogen synthesis in human skeletal muscle. Method: In this cross-over designed study, eight healthy males were categorized into two trials. Subjects in first trial exercised at 70% V.O2max for 60 minutes per day and recovered at sea level (control), and subjects in second trial exercised at 70% V.O2max for 60 minutes per day at sea level and recovered in a hypoxic chamber (living high and training low, LHTL) for 7 days in random order. On 8th day, subjects in both trials performed a 60-min cycling exercise at 70% V.O2max, and subsequently consumed a high carbohydrate meal. Biopsied muscle samples were obtained from vastus lateralis immediately and 4 h after exercise. Blood samples were collected before exercise, immediately after exercise, and for every 30 min during 4-h post-exercise recovery. The same procedures were repeated after three weeks washout period. Result: Muscle glycogen level response at post-exercise 4 h markedly higher in LHTL than in control (p < .05). Both of non-ester fatty acid and glycerol level were markedly lower before exercise, immediately after exercise, and 30 min during recovery period in LHTL compared to control (p < .05). However, blood glucose, blood glucose area under curve, insulin, insulin area under curve, and cortisol levels were not altered between trails (p > .05). Conclusion: LHTL could increase the rate of muscle glycogen synthesis immediately after a single bout of exercise and promote glucose uptake as result to enhance glycogen supercompensation in humans.