動物實驗指出綠茶萃取物(green tea extract, GTE)補充可促進脂肪氧化的作用,節省運動期間的肝醣分解,提升衰竭運動表現。本研究目的在探討人體單次補充去咖啡因綠茶萃取物,明顯提升自行車力竭性運動表現。招募14名健康男性大學生,執行單盲交叉設計,受試者隨機分配進行綠茶試驗(GTE)與安慰劑試驗(placebo),兩次試驗至少間隔七天以上。試驗當天早上受試者食用300kcal的輕食早餐,同時補充含有1,500mg綠茶萃取物膠囊或安慰劑膠囊,安靜休息2小時後執行60%最大功率騎至力竭之原地自行車計時運動挑戰,綠茶或安慰劑補充前、運動前與運動結束後立即採集靜脈血液。研究結果顯示,GTE運動至力竭時間明顯高於placebo;GTE在運動結束時甘油濃度明顯高於Placebo;其他血液指標血糖、游離脂肪酸、血氨、肌酸激酶與尿素濃度皆未達顯著差異,本研究結論認為單次1,500mg去咖啡因綠茶萃取物補充後2小時運動期間能量需求偏向於脂肪分解作用,同時提升自行車計時運動表現。
Animal studies have consistently shown that green tea extract (GTE) can increase energy substrate reliance on fat oxidation, which improves endurance performance due to the glycogen sparing during exercise periods. The purpose of the present study is to demonstrate the effect of acute decaffeinated GTE supplementation prior to exercise on cycling time-trial performance. Fourteen healthy male college students completed a time-trial cycling performance that was assessed at 60% Wmax until exhaustion under 300 kcal breakfast meal consumption with either GTE (1,500 mg) or a placebo capsule two hours before the exercise challenge, using a single-blind crossover design separated by one week. Blood samples were collected before meal ingestion, prior to exercise, and immediately after exercise. The results showed that acute GTE supplementation significantly improved cycling performance to exhaustion compared to the placebo. Serum glycerol concentration was notably higher immediately after exercise in GTE compared to the placebo trial. However, blood parameters regarding glucose, non-esterified fatty acid, ammonia, serum urea, and creatine kinase were unchanged between the two trials. We conclude that 1,500 mg GTE supplementation improves cycling performance due to increased energy substrate reliance on fat oxidation during an exercise period.