有氧運動前增補咖啡因對健康成年男性運動後低血壓與肱踝脈波傳導速率之影響

Effect of pre-exercise caffeine supplement on post-exercise hypotension and brachial-ankle pulse wave velocity to aerobic exercise in healthy adult men

緒論：運動後會產生短暫的血壓下降現象，稱之為運動後低血壓（post exercise hypotension, PEH），被認為是運動有利於降低高血壓患者血壓的可能機制，同時運動也有助於動脈硬化指標－脈波傳導速率（pulse wave velocity, PWV）的降低；然而，咖啡因（caffeine）是一項常見的運動增補劑，其對血壓與PWV的影響與運動相反，且咖啡因結合運動對血壓與PWV的影響仍需進一步釐清。本研究的目的在探討單次中強度有氧運動前增補咖啡因對運動後低血壓與PWV的影響。方法：研究對象為10名健康大專男生，依雙盲設計及平衡次序法分別接受咖啡因+運動（CE, 6 mg／kg）、安慰劑＋運動（PE）及咖啡因控制（CC）三種處理，其中CE與PE處理於增補後30分鐘，進行持續30分鐘70％ HRR（heart rate reserve, HRR）強度的跑步機運動，並於增補前（T1）、增補後30分鐘／運動前（T2）、運動後30分鐘（T3）、60分鐘（T4）及120分鐘（T5）檢測血壓與肱踝脈波傳導速率（baPWV），而CC處理則僅進行咖啡因增補，但不進行運動。本研究採重複量數二因子變異數分析進行統計處理。結果：收縮壓在處理與時間因子的交互作用達顯著（p＝.003），單純主要效果比較顯示PE處理的收縮壓在T4及T5皆顯著低於CC處理，CE在T5也顯著低於CC處理，CE與PE處理的收縮壓在各時間點均無顯著差異；而平均動脈壓（mean arterial pressure, MAP）在處理與時間因子的交互作用也達顯著（p＝.020），單純主要效果比較顯示PE處理的MAP在T3、T4及T5皆顯著低於CC處理，CE在T5也顯著低於CC處理，CE與PE處理各時間點之MAP無顯著差異。另外，baPWV在處理與時間因子的交互作用亦達顯著差異（p＜.001），CE處理在T3及T5的baPWV顯著低於CC處理，PE處理在T4及T5也顯著低於CC處理，而CE與PE處理的baPWV在各時間點均無顯著差異。結論：咖啡因增補會引發收縮壓與脈波傳導速率的顯著提升，但此上升現象會因從事有氧運動而抵消，健康成年男性從事有氧運動前增補咖啡因可能不會對周邊動脈造成短暫不良的影響。

Introduction: Post-exercise hypotension (PEH) induced transiently lowers blood pressure after exercise, and that could be a conducive mechanism to reduce blood pressure associated with hypertension. Simultaneously, exercise is beneficial in diminishing the marker for arterial stiffness (pulse wave velocity, PWV). In contrast to exercise, a caffeine supplement is adverse to blood pressure and PWV. However, it is still unknown what the effects are from the combination of caffeine and exercise on blood pressure and PWV. The purpose of this study was to investigate the effect of caffeine on PEH and PWV after moderately intense aerobic exercise. Methods: Ten healthy college males participated in this randomized, double-blind design study. Participants were asked to perform three different trials: caffeine plus exercise (CE, 6 mg/kg), placebo plus exercise (PE), and caffeine control (CC). Both CE and PE trials were performed with 30 min of running at 70% heart rate reserve (HRR) after 30 min of rest and oral supplements, and a CC trial without exercise. Blood pressure and brachial-ankle PWV (baPWV) were measured pre-supplement (T1), 30 min after supplement/pre-exercise (T2), and 30 min (T3), 60 min (T4), and120 min (T5) after exercise. Two-way repeated-measure ANOVA was used to compare the differences among trials and times. Results: The interaction effects of trials and time on systolic blood pressure (SBP) were statistically significant (p = .003). The simple main effect indicated that systolic blood pressure of PE at T4 and T5 were significantly lower than the CC trial. In addition, the systolic blood pressure of CE at T5 was significantly lower than the CC trial, but there was no significant difference between CE and PE trials. Then, there were statistically significant differences in mean arterial pressure (MAP) between trials and time points (p = .020). The simple main effect indicated that MAP of PE at T3-T5 was significantly lower than the CC trial. In addition, the MAP of CE at T5 was significantly lower than the CC trial, but no significant differences were found between CE and PE trials. Moreover, the index of baPWV was statistically significant (p < .001). That at T3, T5 in CE and T4, T5 in PE were all lower than the CC trial, but there was no difference in CE and PE. Conclusions: Supplies of caffeine could increase systolic blood pressure and PWV, but was offset by aerobic exercise. Caffeine supply, combined with aerobic exercise, will not have a negative impact on temporal peripheral arterial stiffening among healthy adult men.