咖啡因攝取時機對阻力運動後睪固酮與皮質固醇反應之影響

Timing Effects of Caffeine Ingestion on Acute Testosterone and Cortisol Responses to Resistance Exercise

緒論：本研究主要目的在探討不同咖啡因攝取時機對於阻力運動後荷爾蒙反應之影響。方法：本研究以12名有阻力訓練習慣之男性為受試者 (age, 21.4±1.9 yr; mass, 70.1±4.8 kg)。所有受試者在實驗前皆接受最大肌力 (1RM) 測驗，隨後以重複量數與對抗平衡次序分配進行運動前60分鐘攝取 (PRE60, 6 mg/kg)、運動前立即攝取 (PRE-EXE, 6 mg/kg)、運動中攝取 (EXE, 6 mg/kg) 與控制 (CON) 等4次實驗處理，每次實驗間隔7天，受試者按實驗處理攝取咖啡因，隨後進行阻力運動 (5組；75%1RM強度進行10次反覆；2個動作；每組休息時間為2分鐘)。在安靜休息期 (baseline, BL) 與運動後0、15、30分鐘 (P0、P15、P30) 血液進行分析。本研究以相依樣本二因子 (攝取時機×時間) 變異數分析 (ANOVA) 咖啡因攝取時機對荷爾蒙的反應 (睪固酮與皮質固醇) 與能量代謝指標 (血糖、血乳酸、血中游離脂肪酸) 之間是否有顯著差異。顯著水準α訂為.05。結果：在咖啡因攝取後，PRE60的血清游離脂肪酸與CON有顯著差異 (FFA: 0.57±0.09 vs. 0.41±0.10 mmol/L, p < .05)，而血清睪固酮 (P0, P15, P30) (PRE60: 676.75±145.82, 643.38±149.25 and 575.50±192.44; PRE-EXE: 654.25±121.23, 619.50±121.63 and 573.25±125.01 vs. CON: 584.75±136.19, 531.25 ±146.57 and 496.38±137.42 ng/dl, p < .05) 與皮質固醇 (P0, P15, P30) (PRE60: 23.31±3.00, 22.02±2.16 and 20.13±2.78; PRE-EXE: 22.29±2.84, 21.86±2.23 and 20.3±4.40 vs. CON: 18.40±2.30, 17.92 ±2.41 and 16.21±2.10 µg/dl, p < .05) 的反應則顯著高於CON。結論：本研究結果指出阻力運動前攝取咖啡因 (PRE60 and PRE-EXE) 會顯著影響阻力運動後立即之同化性與異化性荷爾蒙的反應，但是在運動中攝取則皆無顯著影響。

 

Introduction: The purpose of this study was to examine the effects of different caffeine ingestion timing on hormonal responses immediate after resistance exercise (RE). Methods: Twelve university male students (age, 21.4±1.9 yr; mass, 70.1±4.8 kg) who regularly performed RE participate in this study. All subjects performed 1RM test, then assigned to four treatments: caffeine ingestion 60 min prior to RE (PRE60, 6 mg.kg-1), caffeine ingestion immediately prior to RE (PRE-EXE, 6 mg.kg-1), caffeine ingestion during RE (EXE, 6 mg.kg-1) and control (CON) in counter balance order and within subject crossover design. All subjects ingested caffeine according to each treatment, then, the subjects performed RE (two exercises, 5 sets of 10 repetitions at 75% of 1RM). Blood samples were collected prior to caffeine ingestion (baseline, BL) and 0, 15, 30 min post to RE (P0, P15, P30) for analysis of testosterone, cortisol, blood lactic acid, glucose and free fatty acid. Each experiment separated by 7 days. In this study, statistical analysis of a two-way analysis of variance (treatment by time) with repeated measures was applied. Statistical significance set at α=.05. Results: After ingesting caffeine, the concentration of free fatty acid (P0) in PRE60 was significantly higher than CON (0.57±0.09 vs. 0.41±0.10 mmol/L) (p < .05). The responses of testosterone (P0, P15, P30) (PRE60: 676.75±145.82, 643.38±149.25 and 575.50±192.44; PRE-EXE: 654.25±121.23, 619.50±121.63 and 571.25±123.97 vs. CON: 584.75±136.19, 531.25 ±146.57 and 496.38±137.42 ng/dl, p < .05) and cortisol (P0, P15, P30) (PRE60: 23.31±3.00, 22.02±2.16 and 20.13±2.78; PRE-EXE: 22.29±2.84, 21.86±2.23 and 20.3±4.40 vs. CON: 18.40±2.30, 17.92 ±2.41 and 16.21±2.10 µg/dl, p < .05) were significantly higher than CON in PRE60 and PRE-EXE. Conclusion: The results of this study indicated that caffeine ingestion prior to RE (PRE60 and PRE-EXE) will significant affect the acute hormonal responses. However, caffeine ingestion during RE might not significantly change acute responses of anabolic and catabolic hormones.