有氧運動訓練強度對中老年人執行功能之影響

Effects of Aerobic Training Intensity on Executive Functions in Middle-to-Old Age Adults

近年來許多研究指出，以有氧運動訓練方式提升中、老年人身體活動量，可促進其認知功能。然而，這些實驗多半直接比較訓練組與對照組之差異，實驗結果僅能提供關於「有」與「無」訓練的前、後測差異。關於不同訓練參數對認知能力的影響，則只能藉由統合性分析推估。本研究目的在探討不同強度之長期有氧運動訓練，對於中、老年人三種不同的中央執行功能影響。我們在篩選後招募中、老年人共四十人，隨機分為兩組以保留心跳率之40%（低等強度）及60%（中等強度）進行三個月的有氧飛輪訓練，並且於訓練第一週、第六週及第十二週，對兩組受試者進行三種中央執行功能成份，進行訓練前、後急性效果的測量。結果發現：中等強度訓練比低等強度訓練有效提升體適能指標（六分鐘行走距離）；在中央執行功能的轉換（shifting）、干擾抑制（inhibition）以及訊息更新（updating）等三種成份表現上，只有轉換能力的混合代價（mixing cost）指標呈現訓練強度與急性階段以及長期訓練時間點的交互作用，其餘成份皆未有此效果。有氧訓練強度差異並非一致性地影響中央執行功能的所有成份運作效能；較高強度訓練會選擇性地在作業轉換功能上展現其優勢。

The beneficial effects of physical exercise, especially aerobic training, on cognitive functions in middle or old age adults have been demonstrated in a sizable amount of recent studies. However, the majority of these research works mainly contrasts the difference between the training and the non-training control groups. Hence their results only reflect the pre- vs. post-training difference between groups “with” and “without” training, and do not reveal the training effect parametrically. The current study aims to investigate how aerobic training with different intensity influences executive functions in middle-to-old age people. Two groups of middle-to-old adults were recruited and randomly assigned to a low-intensity (40% HRR) and a moderate intensity (60% HRR) group for a 12-week cyclic ergometer training program. Tests for components of executive functions, including shifting, inhibition, and updating, were administered immediately before, during, and immediately after the training program. We found that moderate intensity training effectively enhanced physical fitness, in terms of six-minute walking distance, to a larger extent than low intensity. Among the three components of executive function, only the mixing cost of task-switching showed dependence on training intensity in terms of both acute and long-term effect. In conclusion, intensity of aerobic training does not uniformly modulate all components of executive function.