Volterman Kimberly A, Obeid Joyce, Wilk Boguslaw, Timmons Brian W
Child Health and Exercise Medicine Program, Department of Pediatrics, McMaster University, Hamilton, ON L8S 4K1, Canada.
Appl Physiol Nutr Metab. 2014 Nov;39(11):1257-64. doi: 10.1139/apnm-2014-0047. Epub 2014 Jul 7.
Low-fat milk is thought to be an effective postexercise rehydration beverage in adults; however, little is known about milk's rehydration ability in children after exercising in the heat. This study tested the hypothesis that because of its electrolyte and protein content, skim milk (SM) would be more effective than both water (W) and a carbohydrate/electrolyte solution (CES) in replacing body fluid losses in children following exercise in the heat. Thirty-eight (19 females) heat-acclimated pre- to early pubertal (PEP, aged 7-11 years) and mid- to late-pubertal (MLP, aged 14-17 years) children performed 3 sessions in 34.5 °C, 47.3% relative humidity, consisting of 2 × 20-min cycling bouts at 60% peak oxygen uptake followed by consumption of either W, CES, or SM. Each beverage was consumed immediately after exercise in a volume equal to 100% of their body mass loss during exercise. Urine samples were collected before, during, and after exercise, as well as the 2-h period following beverage consumption. On average, children dehydrated 1.3% ± 0.4%. Children ingested 0.40 ± 0.11 L (PEP) and 0.74 ± 0.20 L (MLP) of fluid. The fraction of the ingested beverage retained at 2 h of recovery was greater with SM (74% ± 18%) than W (47% ± 26%) and CES (59% ± 20%, p < 0.001 for both), and greater in CES than W (p < 0.001). All participants were in a hypohydrated state after 2 h of recovery, following the pattern SM < CES < W. In both PEP and MLP children, SM is more effective than W and CES at replacing fluid losses that occur during exercise in the heat.
低脂牛奶被认为是成年人运动后有效的补水饮料；然而，对于儿童在炎热环境中运动后牛奶的补水能力知之甚少。本研究检验了以下假设：由于其电解质和蛋白质含量，脱脂牛奶（SM）在炎热环境中运动后的儿童补充体液损失方面比水（W）和碳水化合物/电解质溶液（CES）更有效。38名（19名女性）经过热适应的青春期前至青春期早期（PEP，7 - 11岁）和青春期中期至晚期（MLP，14 - 17岁）儿童在34.5°C、相对湿度47.3%的环境中进行了3次训练，包括以60%的峰值摄氧量进行2×20分钟的骑行，随后饮用W、CES或SM。每种饮料在运动后立即饮用，饮用量等于其运动期间体重损失的100%。在运动前、运动期间、运动后以及饮用饮料后的2小时内收集尿液样本。平均而言，儿童脱水1.3%±0.4%。儿童摄入了0.40±0.11升（PEP）和0.74±0.20升（MLP）的液体。恢复2小时后，SM保留的摄入饮料比例（74%±18%）高于W（47%±26%）和CES（59%±20%，两者p均<0.001），且CES高于W（p<0.001）。恢复2小时后，所有参与者均处于轻度脱水状态，模式为SM < CES < W。在PEP和MLP儿童中，SM在补充炎热环境中运动期间发生的体液损失方面比W和CES更有效。
