Adams J D, Kavouras Stavros A, Robillard Joseph I, Bardis Costas N, Johnson Evan C, Ganio Matthew S, McDermott Brendon P, White Michael A
1Department of Health, Human Performance, and Recreation, Human Performance Laboratory, University of Arkansas, Fayetteville, Arkansas; and2Sun Prairie Storm Swim Club, Racine, Wisconsin.
J Strength Cond Res. 2016 Mar;30(3):621-5. doi: 10.1519/JSC.0000000000001132.
Swimming, either competitively or leisurely, is a unique activity that involves prolonged exercise while immersed in stable water temperatures. This environment could have an influence on the hydration status of swimmers independently of fluid balance. Forty-six healthy adolescent swimmers (26 males and 20 females; 12.8 ± 2.3 years; 50.6 ± 13.4 kg) were studied during a typical training session in an indoor swimming pool. First morning, prepractice and postpractice urine samples were tested for osmolality and specific gravity, whereas all athletes consumed fluids ad libitum. Sixty-seven percent of the athletes were hypohydrated (urine osmolality [Uosm] ≥700 mmol·kg(-1)) based on their first morning urine sample, which increased to 78% immediately before training. During the 2-hour swimming practice, the minimal sweat loss (0.39 ± 0.27 L) combined with ad libitum fluid availability resulted in unchanged body weight (0.1 ± 0.3 kg). Additionally, thirst was similar (before practice: 46 ± 26, after practice: 55 ± 33 mm on a 100-mm visual analog scale) at pretraining and posttraining time points (p > 0.05). Interestingly, postpractice Uosm was reduced significantly compared with the prepractice value (630 vs. 828 mmol·kg(-1); p = 0.001), without any significant change in body weight (0.1 ± 0.3 kg; p > 0.05). In conclusion, the present data indicated that more than two-thirds of the young swimmers appeared in their practice suboptimally hydrated. Although no changes in body mass were observed during the swimming practice, the decrease in urine hydration markers after swimming might less accurately reflect hydration state.
无论是竞技游泳还是休闲游泳，都是一项独特的活动，需要在水温稳定的水中进行长时间锻炼。这种环境可能会独立于液体平衡对游泳者的水合状态产生影响。在室内游泳池的一次典型训练期间，对46名健康的青少年游泳者（26名男性和20名女性；年龄12.8±2.3岁；体重50.6±13.4千克）进行了研究。在第一天早晨、训练前和训练后采集尿液样本，检测尿渗透压和比重，而所有运动员可随意饮水。根据第一天早晨的尿液样本，67%的运动员处于轻度脱水状态（尿渗透压[Uosm]≥700 mmol·kg⁻¹），在训练前这一比例增至78%。在2小时的游泳训练期间，最小出汗量（0.39±0.27升）加上可随意获取的液体，导致体重没有变化（0.1±0.3千克）。此外，在训练前和训练后的时间点，口渴程度相似（训练前：100毫米视觉模拟量表上为46±26，训练后：55±33毫米；p>0.05）。有趣的是，与训练前的值相比，训练后的尿渗透压显著降低（630对828 mmol·kg⁻¹；p = 0.001），而体重没有任何显著变化（0.1±0.3千克；p>0.05）。总之，目前的数据表明，超过三分之二的年轻游泳者在训练时水合状态欠佳。虽然在游泳训练期间未观察到体重变化，但游泳后尿液水合指标的下降可能无法准确反映水合状态。
