間歇低氧訓練對有氧適能與心率變異性表現之影響

Abstract

間歇性常壓低氧訓練是藉由低濃度氧氣製造器，營造常壓低氧環境， 訓練操作爲吸入低氧混合氣 5 至 15 分鐘，再間歇吸入一般正常空氣 5 至 15 分鐘，一次訓練重複 4 至 6 次循環，以 5 至24 天爲一訓練階段。研究 目的：探討連續15 日間歇低氧刺激結合運動訓練對有氧運動能力與心臟 自主神經系統調控之影響。研究方法： 30 位男性運動員隨機分配為間歇 低氧運動訓練組（intermittent hypoxic training, IH+E, 12%O2; N=10）、間 歇常氧運動訓練組（intermittent normoxia training, IN+E, 21%O2; N=10）與 間歇低氧未運動訓練組（intermittent hypoxic control group, IH, 12%O2; N=10）等三組。連續執行 15 日間接低/常氧刺激，結合踩踏腳踏車功率器 運動訓練/安靜操作 5 分鐘，間接常氧休息恢復 5 分鐘，配合運動負荷為 65% 攝氧峰值負荷強度，共 6 循環計 60 分鐘，紀錄實驗操作前後之心率 與呼吸頻率變異性；另評估 15 日實驗操作前、後之有氧運動能力（攝氧 峰值、乳酸閾值作功值）及相關生理調控表現（身體組成、血液學指標、 兒茶酚胺濃度）之變化。結果：一、間歇低氧運動訓練組顯著提升紅血球 生成素（23%）、網狀紅血球計數（10.4%）與血紅素（14.7%）之生理表 現，另亦增加攝氧峰值（26.7%）與乳酸閾值作功值（43.9%）等有氧運動 能力；二、各組間身體組成並無差異；三、間歇低氧運動訓練組經連續15 日間歇低氧刺激結合運動訓練後，其耗竭運動後去甲基腎上腺素分泌濃度 變化率提升206.2%， 明顯高於其他二組；四、連續15 日間歇低氧結合運 動訓練初期調控心臟之自主神經系統活性下降47.3%，副交感神經系統活 性下降64.3%，另交感神經系統活性於初期顯示先迅速增加再行劇烈下降 之震盪趨勢，三者均於中、後訓練階段逐步提升，顯示為適應間歇低氧結 合運動訓練之強烈刺激，體內乃誘發較佳之自主神經系統調控心臟能力； 然而身體須於訓練初期忍受自主神經系統驅策力之劇烈震盪調適。結論： 結合運動之間歇低氧訓練有利於強化有氧運動能力，並誘發體內較佳之自 主神經系統調控驅策心臟能力；然而為確保訓練初期體內自主調適之安全 性，需於運動訓練過程，針對心率變異性加以持續監控。Objective: Interval normobaric hypoxic training (IHT) consists of repeated (three to more times) short periods (5-15 min each) of steady or progressive hypoxia, interrupted by similar periods of rest/recovery. Aim: to determine the effects of IHT on aerobic endurance and cardiac autonomic modulation in adolescents. Method: Thirty male adolescents completed a 15 days IHT regimen (5:5-min hypoxia-to-normoxia ratio for 60 min) of intermittent normobaric hypoxia (12%O2) combining 65% peak oxygen comsumption (V ‧ O2peak) (IH+E), intermittent normobaric normoxia (21%O2) combining 65% V ‧ O2peak (IN+E) or intermittent normobaric hypoxia (12%O2) only at rest (IH). Transfer function analysis of heart rate variability (HRV) and respiration were measured during IHT used to characterize low- (mainly sympathetic) and high-frequency (vagal) cardiovascular fluctuations. Before and after IHT experimental protocol, we recorded body composition and hematologic indexes at rest in the morning. Subjects were performed the incremental exercise test. Lactate threshold (LT), V ‧ O2peak and catecholamines changes (CAs) were determined to refer as the aerobic capacity. Results: (1)There were significantly increased hematologic indexes in EPO (23%), reticularcyte count (10.4%) and hemoglobin (14.7%) after IHT in IH+E. (2)No significant changes were found on body composition. (3)The performances of LT (43.9%) and relatived V ‧ O2peak（ 26.7%）were improved after IHT in IH+E. Plasma noradrenaline level after exhaustion test were increasing 206.2% significantly in IH+E. (4) IHT decreased sympathovagal tone in the initial stage and recovered progressively in later period. Chronic IHT combining exercise induced better sympathovagal balance, leading to greater tolerance of chronic hypoxia. Conclusion: These results suggested that exercise in combination with IHT might have a benefit for the aerobic performance and cardiac autonomic modulation.