褪黑激素(Melatonin)是松果體分泌的荷爾蒙，具有夜高晝低的日夜節律(circadian rhythm)分泌特性。對於人體有助眠、降血壓、促進免疫力、清除自由基、增進抗氧化能力及抑制腫瘤壞死因子等生理益處。運動對於褪黑激素的影響，可能與運動時段、環境照明度、運動強度及持續時間有關。目前已知單次運動方面：白天運動褪黑激素的濃度會有短暫上升的現象或維持不變，夜間運動反而會減緩褪黑激素分泌；至於長期運動方面：漸進性的運動使褪黑激素濃度上升，劇烈運動會使褪黑激素動降低。未來研究可朝褪黑激素與過度訓練的關聯性加以邁進，為運動訓練和運動保健帶來新的契機。

Melatonin is a hormone which is secreted by the pineal gland. The secretion of its circadian rhythm is higher in the nighttime and lower in the daytime in characteristic. The physiological benefits of melatonin for humans are aiding sleep, reducing blood pressure, stimulating immune function, scavenging free radicals, enhancing antioxidative capacity, suppressing tumor necrosis factor and so on. The influence of exercise upon plasma melatonin may be related with the exercise time of day, circumstance illumination, exercise intensity and duration. At present we have known the aspect of single bout of exercise upon plasma melatonin as follows: exercise in the daytime elicits transient increases or keeps unchanged in plasma melatonin, but exercise at night blunts the nocturnal increase of plasma melatonin levels; As for the aspect of long term exercise: progressive exercise would rise plasma melatonin concentration, but vigorous exercise would diminish it. The future research can step toward the relevance of melatonin to overtraining to carry the new moment for sports training and sports health care.

褪黑激素; 日夜節律

Melatonin; Circadian rhythm