咖啡因對中高強度間歇運動後超額攝氧量的影響

Effect of caffeine on excess post exercise oxygen consumption after moderate-high intensity interval exercise

目的：探討咖啡因對中高強度間歇運動後超額攝氧量（excess post exercise oxygen consumption，EPOC）的影響。方法：8位健康男性受試者（年齡：24.4±0.3歲、身高：174.7±2.4公分；體重：70.8±2.8公斤；V.O2peak：38.6±1.7mg/kg/min）參與兩次平衡交叉，雙盲且間隔至少一週的實驗處理，一次攝取250毫克的咖啡因膠囊，一次則為安慰劑，兩次增補後統一安靜休息90分鐘，隨即進行中高強度運動，運動方式為先以60％V.O2peak的強度進行腳踏車運動20分鐘後，再進行3組80％V.O2peak運動1分鐘，休息1分鐘的間歇性腳踏車運動。採集受試者攝取咖啡因或安慰劑後第0、25、55、85分鐘之安靜心跳率（heart rate，HR）、呼吸交換率 （respiratory exchange ratio，RER）及攝氧量（oxygenuptake，V.O2）。實驗過程中也採集受試者增補前（pre-90）、運動前立即（pre-exe）、運動後恢復期的第4分鐘、240分鐘及480分鐘（post-4、post-240、post-480）之前臂靜脈血液，以及運動後60分鐘之攝氧量。統計方法以相依樣本t考驗檢定總EPOC、快速期EPOC及慢速期EPOC；以重複量數雙因子（treatment╳time）變異數分析考驗HR、RER、V.O2及血乳酸濃度之交互作用及差異顯著情形。結果：安靜攝氧量部分，時間與組別交互作用達顯著（F=7.68，p=.028），咖啡因處理在第25分鐘（5.50±0.36ml/kg/min，p=.004）、第55分鐘（5.17±0.21ml/kg/min，p=.032）及第85分鐘（5.36±0.23ml/kg/min，p=.010）之攝氧量，皆顯著高於第0分鐘（4.35±0.19ml/kg/min）。EPOC部分，僅咖啡因處理（750.86±91.39ml）之EPOC快速期顯著高於安慰劑處理（600.27±72.19ml）（p=.043）。結論：攝取250mg咖啡因可顯著增加安靜時代謝速率，及中高強度間歇運動後之能量消耗，若日後欲進行中高強度間歇運動，且欲增加能量消耗時，建議可於運動前搭配攝取咖啡因。To investigate the effect of caffeine on excess post exercise oxygen consumption (EPOC) after moderate-high intensity exercise. Method: Eight healthy males (age: 24.4 ± 0.3 yr, height: 174.8 ± 2.4 cm, weight: 70.8 ± 2.8, V.O2peak: 38.6 ± 1.7 ml/kg/min) attended two randomized, cross-over, double-blind trials at least one week apart, one with 250 mg caffeine (Caf) and one with placebo (0 mg caffeine; Pla), and after 90 min rest then completed each exercise session (ES) on cycle ergometer. ES consisting of 20 min of cycling at 60% V.O2peak follow by 3 sets of 1-min cycling at 80% V.O2peak with a 1-min rest between sets. During each ES, resting V.O2 and 60-min post-exercise V.O2 were measured. Blood sample were drawn at 90 min before exercise, pre - exercise, and 30 min, 240 min, 480 min after exercise. Plasma was analyzed for lactate. V.O2 was measured for the 60 min after the exercise. Data from total EPOC, fast phase EPOC, and slow phase EPOC were analyzed by paired t-tests and p < .05 was considered statistically significant. HR, RER, V.O2 and lactate were compared initially through two-way (treatment × time) ANOVA with repeated measures. Result: No significant difference in HR and RER. However, the interaction effect of treatment and time on V.O2 was statistically significant (F = 7.68, p = .028). V.O2 was significantly increased at 25 (5.50 ± 0.36 ml/kg/min), 55 (5.17 ± 0.21 ml/kg/min) and 85 min (5.36 ± 0.23 ml/kg/min) than before (4.35 ± 0.19 ml/kg/min) (p = .004, p = .032, p = .010) supplementation in caffeine trail. Fast phase of EPOC in caffeine trail was significantly higher than placebo (750.86 ± 91.39 ml vs. 600.27 ± 72.19 ml, p = .043). Conclusion: Ingestion of caffeine 250 mg could increase the ratio of rest metabolism, as well as after middle- high intensity interval exercise.