O'Hara John P, Carroll Sean, Cooke Carlton B, King Roderick F G J
1Research Institute for Sport, Physical Activity and Leisure, Leeds Metropolitan University, Leeds, United Kingdom; and 2Department of Sport, Health and Exercise Science, University of Hull, Hull, United Kingdom.
J Strength Cond Res. 2014 Aug;28(8):2145-53. doi: 10.1519/JSC.0000000000000372.
This study evaluated the effects of the pre-exercise (30 minutes) ingestion of galactose (Gal) or glucose (Glu) on endurance capacity as well as glycemic and insulinemic responses. Ten trained male cyclists completed 3 randomized high-intensity cycling endurance tests. Thirty minutes before each trial, cyclists ingested 1 L of either 40 g of glucose, 40 g of galactose, or a placebo in a double-blind manner. The protocol comprised 20 minutes of progressive incremental exercise (70-85% maximal power output [Wmax]); ten 90-second bouts at 90% Wmax, separated by 180 seconds at 55% Wmax; and 90% Wmax until exhaustion. Blood samples were drawn throughout the protocol. Times to exhaustion were longer with Gal (68.7 ± 10.2 minutes, p = 0.005) compared with Glu (58.5 ± 24.9 minutes), with neither being different to placebo (63.9 ± 16.2 minutes). Twenty-eight minutes after Glu consumption, plasma glucose and serum insulin concentrations were higher than with Gal and placebo (p < 0.001). After the initial 20 minutes of exercise, plasma glucose concentrations increased to a relative hyperglycemia during the Gal and placebo, compared with Glu condition. Higher plasma glucose concentrations during exercise, and the attenuated serum insulin response at rest, may explain the significantly longer times to exhaustion produced by Gal compared with Glu. However, neither carbohydrate treatment produced significantly longer times to exhaustion than placebo, suggesting that the pre-exercise ingestion of galactose and glucose alone is not sufficient to support this type of endurance performance.
本研究评估了运动前（30分钟）摄入半乳糖（Gal）或葡萄糖（Glu）对耐力以及血糖和胰岛素反应的影响。十名经过训练的男性自行车运动员完成了3次随机高强度自行车耐力测试。在每次试验前30分钟，自行车运动员以双盲方式摄入1升含有40克葡萄糖、40克半乳糖或安慰剂的溶液。测试方案包括20分钟的渐进性增量运动（最大功率输出[Wmax]的70 - 85%）；以Wmax的90%进行十次90秒的运动回合，回合之间以Wmax的55%持续180秒；然后以Wmax的90%持续到力竭。在整个测试过程中采集血样。与摄入Glu（58.5±24.9分钟）相比，摄入Gal时的力竭时间更长（68.7±10.2分钟，p = 0.005），两者与安慰剂组（63.9±16.2分钟）相比均无差异。摄入Glu后28分钟，血浆葡萄糖和血清胰岛素浓度高于摄入Gal和安慰剂时（p < 0.001）。在最初20分钟的运动后，与摄入Glu的情况相比，摄入Gal和安慰剂时血浆葡萄糖浓度升高至相对高血糖状态。运动期间较高的血浆葡萄糖浓度以及休息时血清胰岛素反应减弱，可能解释了与摄入Glu相比，摄入Gal导致力竭时间显著更长的原因。然而，两种碳水化合物处理方式导致的力竭时间均未显著长于安慰剂组，这表明运动前单独摄入半乳糖和葡萄糖不足以支持此类耐力表现。
