緒論：有氧運動可以降低動脈硬化指標－脈波傳導速率(pulse wave velocity, PWV)及血壓。相反的，立即性咖啡因增補會使PWV及血壓上升，但有氧運動降低PWV及血壓的效益是否會因運動後立即增補咖啡因而抵消仍有待釐清。本研究旨在探討有氧運動後增補咖啡因對踝臂脈波傳導速率(brachial-ankle pulse wave velocity, baPWV)及血壓的影響。方法：招募12名無規律運動及無飲用咖啡因習慣之健康男性，依平衡次序與雙盲原則，先進行70%儲備心跳率強度之跑步機運動30分鐘，接著以每公斤體重6 mg的咖啡因(Caf)或安慰劑(Pla)立即增補，並於運動前和運動後30、60、90及120分鐘檢測baPWV及血壓。統計採用重複量數二因子變異數分析。結果：baPWV之交互作用達顯著(p=.001)，Caf之baPWV在運動後30、60、90及120分鐘皆顯著高於Pla (p <.05)；收縮壓之交互作用達顯著(p<.001)，Caf之收縮壓在運動後30、60、90及120分鐘皆顯著高於Pla (p<.05)。平均動脈壓之交互作用達顯著(p=.001)，Caf之平均動脈壓在運動後30、60、90及120分鐘皆顯著高於Pla (p<.05)。另外，Caf之baPWV及收縮壓在運動後120分鐘顯著高於運動前(p<.05)，而平均動脈壓在運動後30、90及120分鐘皆顯著高於運動前(p<.05)；Pla之baPWV在運動後60及90分鐘皆顯著低於運動前(p<.05)，收縮壓在運動後30、60及90分鐘皆顯著低於運動前(p<.05)，而平均動脈壓在運動後各時間點皆與運動前無差異(p>.05)。結論：有氧運動降低baPWV及血壓的效益會因運動後立即增補咖啡因而抵消，甚至造成baPWV及血壓上升。若欲降低baPWV及血壓，建議運動後90分鐘期間避免一次增補每公斤體重6 mg的咖啡因。

Introduction: Aerobic exercise decreases pulse wave velocity (PWV) and blood pressure, whereas caffeine intake acutely increases both. However, whether caffeine consumption immediately after exercise offsets the beneficial effects of aerobic exercise on PWV and blood pressure remains unknown. The purpose of this study was to examine the effects of caffeine intake after aerobic exercise on brachial-ankle pulse wave velocity (baPWV) and blood pressure. Methods: Twelve healthy males were recruited for the investigation. None of the subjects exercised or consumed caffeine regularly. A counterbalanced double-blind experiment was performed. First, all subjects performed a running exercise on the treadmill at an intensity of 70% heart rate reserve for 30 minutes. Then, caffeine (6 mg/kg body weight) or a placebo was taken immediately. baPWV and blood pressure were measured before exercise and 30, 60, 90, and 120 minutes after exercise. The variables were analyzed using two-way ANOVA with repeated measures. Results: A significant interaction was found between caffeine treatment and baPWV (p = .001), systolic blood pressure (SBP; p < .001), and mean arterial pressure (MAP; p = .001). On caffeine treatment, baPWV, SBP, and MAP were significantly higher at 30, 60, 90, and 120 minutes after exercise compared to the placebo treatment (p < .05 for all comparisons). In addition, on caffeine treatment, both baPWV and SBP were significantly higher at 120 minutes after exercise and MAP was significantly higher at 30, 90, and 120 minutes after exercise compared to the baseline (p < .05 for all comparisons). On placebo treatment, baPWV was significantly lower at 60 and 90 minutes after exercise and SBP was significantly lower at 30, 60, and 90 minutes after exercise compared to the baseline (p < .05 for both), but MAP did not show a significant change after exercise (p > .05). Conclusion: Caffeine consumption immediately after aerobic exercise offsets the benefits of the exercise for reducing PWV and blood pressure and may even lead to an increase in baPWV and blood pressure. To maintain the reduction in baPWV and blood pressure, we recommend avoiding a caffeine intake of 6 mg/kg at least for 90 minutes after exercise.