綠茶萃取物增補對運動疲勞影響與未來應用潛力評估

A review of green tea supplementation on exercise-induced fatigue

緒論：運動訓練或競技比賽都可能誘發疲勞的現象，無法維持肌力或產生最大爆發力，導致運動表現下降。運動誘發的疲勞可分為中樞與周邊疲勞，可以透過血液生化指標進行評估，進而降低或避免疲勞的發生，以利於訓練的適應或運動後的恢復。適當的營養有助於促進訓練的適應、恢復或是組織的修復。綠茶是天然的茶樹製成，含有豐富的兒茶素與少量咖啡因，可能藉由調控脂肪的代謝與減緩自由基的氧化傷害，達到抗肥胖、抗氧化與抗發炎等生理作用，因此，潛在具有減緩運動疲勞的作用。方法：蒐集增補方式以綠茶萃取物膠囊或其萃取液為主的文獻，其中排除綠茶純化的單一成份之相關文獻。內文則根據肌肉疲勞的代謝變化與機制，依序就能量代謝、氧化壓力與發炎指標等三大類別指標進行討論，以探討綠茶萃取物增補對運動誘發的疲勞、運動表現與運動後恢復期生理機能的影響。結論：一、綠茶萃取物在動物研究上被證實可以提高力竭性運動的脂質代謝，節省肝醣的消耗，以提昇運動表現，但在人體試驗上則未獲得相同的結果。二、中等強度運動已經誘發最大脂肪氧化作用，增補綠茶萃取物無法造成體內脂肪代謝的改變。三、人體連續多天補充綠茶萃取物能促進高強度與阻力／重量訓練之脂肪氧化作用，並降低運動誘發的氧化壓力，但是不會改變運動引起的發炎反應。四、建議未來的人體研究以高強度或阻力／重量運動作為介入，或是提高綠茶萃取物的劑量，觀察對運動疲勞與運動表現的影響。

Introduction: Muscle fatigue during exercise training or competition is defined as the reduction in the ability to produce a give force or maximal muscle power that impairs athletic performance. Exercise-induced fatigue is usually divided into central and peripheral components. Fatigue assessment using blood biochemical markers is often used as a practical method of monitoring training load, fatigue and recovery in athletes. Appropriate nutrition can induce metabolic adaptations to training resulted in the attenuate in fatigue or muscle damage. Green tea is made from the leaves of the Camellia sinensis L plant, which is abundant in polyphenol catechins and less caffeine. The precise mechanisms of green tea regulate fat oxidation and oxidative stress generated by free radicals in relation to anti-obesity, anti-oxidative stress and anti-inflammatory properties, and showed the potential of positive effect in response to fatigue. Methods: A comprehensive literature search was conducted to identify relevant trials of the supplementation of green tea capsules or drinkers. Exclusion criteria were the isolation of the pure ingredients, epigallocatechin gallate (EGCG) from green tea. According to the mechanism and metabolic changes of muscle fatigue during exercise, three categories of biomarkers have been determined, included energy metabolism, oxidative stress and inflammatory biomarkers. We aimed to identify the effects of green tea on exercise-induced fatigue, performance and post-exercise recovery. Conclusion: This review article showed that 1) green tea supplementation would increase lipid metabolism and spare glycogen utilization that is beneficial in enhancing exercise performance in animals, but not in humans. 2) Green tea supplementation could not enough induce the changes in lipid metabolism during moderate intensity exercise that elicits the maximum fat oxidation rate in humans. 3) The evidence from human studies supported these adaptations that result in increased fat oxidation and decreased oxidative stress with high intensity and resistance/weight exercise, but not exercised-induced inflammation. Clearly, future studies are needed to elucidate the effects of high dose green tea with high intensity or resistance/weight exercise on fatigue and performance.