碳水化合物增補對耐力運動時肌肉激素－irisin及能量代謝指標之效應

Abstract

背景：Irisin為骨骼肌所分泌之激素，運動能刺激irisin分泌，促使脂肪產生棕化 (browning) 現象，除了運動本身所造成的能量負平衡外，還可能透過irisin之作用得到整體能量代謝上的益處。目的：本研究旨在探討單次長時間耐力運動與碳水化合物增補對irisin的效應，及其與能量代謝指標間之關係。方法：招募12名有運動習慣的男性，以重複量數、平衡次序之設計，進行跑步運動（70% VO2 max 90分鐘＋90% VO2 max漸增至衰竭）搭配增補碳水化合物或安慰劑兩種實驗處理，且於運動前分別增補高、低碳水化合物比例之飲食。每次實驗於基準值及隔日（24小時）安靜值時分別進行口服葡萄糖耐受度測驗 (OGTT)；運動第20、40、60、80分鐘各增補一次，每次增補每公斤體重2.5毫升、濃度10 % 之碳水化合物溶液，或相同甜度之等量安慰劑溶液。每次實驗共採血六次，分別為基準值、運動前、運動中（第80分鐘）、運動後立即、運動後1小時，及隔日（24小時）安靜值，檢驗血液irisin、葡萄糖、乳酸、胰島素之濃度。另外，實驗過程亦收集呼吸、心跳、自覺量表等數據。結果：碳水化合物增補與安慰劑處理間及各時間點間之irisin濃度無顯著差異 (p > .05)；碳水化合物增補與安慰劑處理間及各時間點間之OGTT數值無顯著差異 (p > .05)；碳水化合物增補處理之高強度運動至衰竭的時間顯著大於安慰劑處理 (318.58 ± 92.67秒vs. 256.42 ± 116.32秒) (p< .05)；碳水化合物增補處理在運動過程中的血糖濃度顯著高於安慰劑處理 (104.17 ± 9.20 mg/dL vs. 83.92 ± 9.54 mg/dL) (p < .05)。結論：單次長時間耐力運動前增補不同碳水化合物比例飲食及運動過程中搭配碳水化合物增補，皆不會改變血液irisin濃度。Background：Irisin is a novel exercise-induced hormone secreted by skeletal muscle and possibly mediating the positive effects of exercise on metabolism via inducing “browning” of adipose tissue or facilitating glucose metabolism in muscle. Purpose: It aimed to investigate the effects of acute endurance exercise and CHO supplementation on irisin levels. Method: 12 young physically active men were recruited and completed two trials in a randomized, double-blinded and crossover design. Each trial consists of a treadmill run at 70% VO2 max for 90 mins and then increasing speed from 90% VO2 max until exhaustion. Every 20 mins during the run, participants consumed CHO solutions (10%, 2.5ml/kg) or PLA solutions of same amount and sweetness. OGTT tests were conducted with over-night fasting at baseline (and 24 hr later) and followed by a standard meal with high/low CHO%, and then the run 1 hr after meals. Irisin, blood glucose, lactate and insulin levels were measured at baseline, pre-exercise, during exercise (the 80th min of run), immediately after exercise and 24 hrs after baseline. Results：There were no significant differences in irisin levels or OGTT between trials and time points (p > .05)；time to exhaustion is higher in CHO trial (318.58 ± 92.67 secs vs. 256.42 ± 116.32 secs) (p< .05)；glucose during exercise is higher in CHO trial (104.17 ± 9.20 mg/dL vs. 83.92 ± 9.54 mg/dL) (p < .05)。Conclusion: Meals with high/low CHO% before and CHO ingestion during acute endurance exercise might not affect irisin levels.