Benton Melissa J, Swan Pamela D
College of Nursing, Valdosta State University, Valdosta, GA 31698, USA.
Int J Sport Nutr Exerc Metab. 2007 Dec;17(6):544-55. doi: 10.1123/ijsnem.17.6.544.
Research suggests that ingesting protein after resistance exercise (RE) increases muscle protein synthesis and results in greater muscle gains. The effect on energy expenditure and substrate utilization, however, is unclear. This study evaluated the effect of RE and postexercise protein on recovery energy expenditure and substrate utilization in 17 women (age 46.5 +/- 1.2 y). A whey-protein supplement (120 kcal, 30 g protein) was ingested immediately after 1 bout of RE (PRO) and a noncaloric placebo after another (PLA).VO2 and respiratory-exchange ratio (RER) were measured before and for 120 min after each exercise session. RE resulted in a significant increase in VO2 that persisted through 90 min of recovery (P < 0.01) and was not affected by protein supplementation. RE significantly lowered RER, resulting in an increase in fat oxidation for both PLA and PRO (P < 0.01). For PRO, however, RER returned to baseline values earlier than for PLA, resulting in a reduced fat-oxidation response (P = 0.02) and earlier return to preexercise baseline values than for PLA. Substrate utilization was significantly different between conditions (P = 0.02), with fat contributing 77.76% +/- 2.19% for PLA and 72.12% +/- 2.17% for PRO, while protein oxidation increased from 17.18% +/- 1.33% for PLA to 20.82% +/- 1.47% for PRO. Postexercise protein did not affect energy expenditure, but when protein was available as an alternate fuel fat oxidation was diminished. Based on these findings it might be beneficial for middle-aged women to delay protein intake after RE to maximize fat utilization.
研究表明，在抗阻运动（RE）后摄入蛋白质可增加肌肉蛋白质合成，并带来更大的肌肉增长。然而，其对能量消耗和底物利用的影响尚不清楚。本研究评估了RE和运动后蛋白质对17名女性（年龄46.5±1.2岁）恢复能量消耗和底物利用的影响。在1次RE后立即摄入乳清蛋白补充剂（120千卡，30克蛋白质）（PRO组），在另一次RE后摄入无热量安慰剂（PLA组）。在每次运动前及运动后120分钟测量VO₂和呼吸交换率（RER）。RE导致VO₂显著增加，该增加在恢复的90分钟内持续存在（P<0.01），且不受蛋白质补充的影响。RE显著降低了RER，导致PLA组和PRO组的脂肪氧化均增加（P<0.01）。然而，对于PRO组，RER比PLA组更早恢复到基线值，导致脂肪氧化反应降低（P = 0.02），且比PLA组更早恢复到运动前基线值。不同条件下的底物利用存在显著差异（P = 0.02），PLA组脂肪供能占77.76%±2.19%，PRO组为72.12%±2.17%，而蛋白质氧化从PLA组的17.18%±1.33%增加到PRO组的20.82%±1.47%。运动后蛋白质摄入不影响能量消耗，但当蛋白质可作为替代燃料时，脂肪氧化会减少。基于这些发现，中年女性在RE后延迟蛋白质摄入以最大化脂肪利用可能是有益的。
