School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, UK.
Int J Sport Nutr Exerc Metab. 2009 Dec;19(6):598-606. doi: 10.1123/ijsnem.19.6.598.
This study investigated fluid and electrolyte balance in well-trained male and female swimmers during 2 training sessions. Participants were 17 nationally ranked swimmers measured during a period of intensive training. Sweat loss was assessed from changes in body mass after correction for fluid intake and urine collection. Sweat composition was measured from waterproof absorbent patches applied at 4 skin sites. Air and pool-water temperatures were 36 degrees C and 27.4 degrees C, respectively. Training lasted 105 min in each session. All measured variables were similar on the 2 testing days. Mean sweat-volume loss was 548 +/- 243 ml, and mean sweat rate was 0.31 +/- 0.1 L/hr. Mean fluid intake was 489 +/- 270 ml. Mean body-mass loss was 0.10 0.50 kg, equivalent to 0.1% +/- 0.7% dehydration. Mean pretraining urine osmolality was 662 +/- 222 mOsm/kg, which was negatively associated with both mean drink volume consumed (p = .044, r = .244) and mean urine volume produced during training (p = .002, r2 = .468). Mean sweat Na+, K+, and Cl- concentrations (mmol/L) were 43 +/- 14, 4 +/- 1, and 31 +/- 9, respectively; values were not different between males and females and were not different between days except for a marginal difference in K+ concentration. The average swimmer remained hydrated during the session, and calculated sweat rates were similar to those in previous aquatic studies.
本研究调查了 2 次训练期间训练有素的男性和女性游泳运动员的液体和电解质平衡。参与者为 17 名全国排名游泳运动员，在强化训练期间进行了测量。通过在 4 个皮肤部位使用防水吸收垫来测量汗液成分，从身体质量的变化来评估汗液损失，在对液体摄入和尿液收集进行校正后。空气和泳池水的温度分别为 36°C 和 27.4°C。每次训练持续 105 分钟。在 2 天的测试中，所有测量的变量都相似。平均汗液损失量为 548 +/- 243 ml，平均出汗率为 0.31 +/- 0.1 L/hr。平均液体摄入量为 489 +/- 270 ml。平均体重损失为 0.10 +/- 0.50 kg，相当于 0.1% +/- 0.7%脱水。训练前尿液渗透压的平均值为 662 +/- 222 mOsm/kg，与平均饮料量（p =.044，r =.244）和训练期间平均尿液量（p =.002，r2 =.468）呈负相关。平均汗液中 Na+、K+和 Cl-浓度（mmol/L）分别为 43 +/- 14、4 +/- 1 和 31 +/- 9；男性和女性之间的数值没有差异，除了 K+浓度略有差异外，两天之间的数值也没有差异。游泳运动员在训练期间保持水分，计算出的出汗率与以前的水上研究相似。
