Isotonic sports drink promotes rehydration and decreases proteinuria following karate training

Abstract Introduction: Adequate hydration status in the sport is essential for good health, yet the relationship between hydration, proteinuria and sports is little studied. Objective: To analyze the influence of an isotonic sports drink as rehydration strategy on the hydration status and proteinuria after karate training. Methods: Ten athletes participated in this study. In the first session of standard training, called observation training session (STO), the athletes hydrated themselves according to their habits, and in the second session of standard training, called nutritional intervention training session (STIN), an ideal practice of hydration protocol was followed, using an isotonic sports drink as a rehydration liquid during the training. The hydration status was verified by monitoring the body weight before and after training, the urine specific gravity pre-and post-training and the urine volume post-training. To observe the influence of practice of hydration on the renal function post exercise proteinuria was measured. Results: We observed a statistically significant difference in urine density between the samples pre- and post-exercise only on STIN (p = 0.047). When we compare the sessions, there was a lower variation in body weight (p = 0.011) and higher urinary volume (p < 0.001), on nutritional intervention training. In STO, there was a higher percentage of athletes who showed proteinuria (70%) compared to the STIN (50%) in the urine sample after training. Conclusion: The use of isotonic sports drink as practice of hydration by karate athletes promoted rehydration during one session of training and reduce post-training proteinuria.

摘要：运动中维持充足的体液水合状态对身体健康至关重要，但目前有关水合作用、蛋白尿（proteinuria）与运动三者间关联的研究仍较为匮乏。
研究目的：分析以等渗运动饮料（isotonic sports drink）作为补液策略，对空手道训练后运动员的体液水合状态及蛋白尿水平的影响。
研究方法：本研究共纳入10名运动员。在首次标准化训练（命名为观察性训练（observation training session, STO））中，运动员按照自身日常习惯进行补液；在第二次标准化训练（命名为营养干预训练（nutritional intervention training session, STIN））中，运动员遵循标准化补液方案，训练期间以等渗运动饮料作为补液介质。本研究通过监测训练前后的体重变化、训练前后的尿比重（urine specific gravity）以及训练后尿量，对受试者的体液水合状态进行评估；同时检测运动后蛋白尿水平，以明确补液方案对肾功能的影响。
研究结果：仅在营养干预训练（STIN）中，训练前后的尿比重存在统计学显著性差异（p=0.047）。对比两次训练，营养干预训练组的体重变化幅度更低（p=0.011），且训练后尿量更高（p<0.001）。训练后尿液样本检测显示，观察性训练组（STO）出现蛋白尿的运动员占比（70%）高于营养干预训练组（50%）。
研究结论：空手道运动员采用等渗运动饮料进行补液，可在训练过程中实现有效体液补充，并降低训练后蛋白尿的发生风险。