Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, PQ J1K 2R1, Canada.
Research Center on Aging, University of Sherbrooke, Sherbrooke, PQ J1H 4C4, Canada.
Nutrients. 2023 Oct 24;15(21):4500. doi: 10.3390/nu15214500.
A drinking strategy aiming to replace a given percentage of the sweat losses incurred during exercise should result in reproducible fluid intake volume and, hence, fluid balance from one exercise session to the other performed under similar scenarios. Whether this may also be the case with ad libitum drinking during exercise is unclear. We characterized the repeatability of ad libitum water intake during repeated 1 h exercise sessions and examined its effect over time on fluid balance and selected physiological functions and perceptual sensations. Twelve (3 women) healthy individuals participated in this study. At weekly intervals, they completed four 2 × 30 min walking/jogging exercise bouts (55% V˙O, 40 °C, 20-30% relative humidity) interspersed by a 3 min recovery period. During exercise, participants consumed water (20 °C) ad libitum. There were no significant differences among the four exercise sessions for absolute water intake volume (1000 mL·h), percent body mass loss (0.4%), sweat rate (1300 mL·h) and percent of sweat loss replaced by water intake (80%). Heart rate, rectal temperature, and perceived thirst and heat stress did not differ significantly between the first and fourth exercise sessions. Perceived exertion was significantly lower during the fourth vs. the first exercise session, but the difference was trivial (<1 arbitrary unit). In conclusion, ad libitum water intake during four successive identical 1 h walking/jogging sessions conducted in the heat will result in similar water intake volumes and perturbations in fluid balance, heart rate, rectal temperature, and perceived thirst, heat stress and exertion.
一种旨在替代运动中因出汗而损失的特定百分比的饮水策略，应该会产生可重复的液体摄入量，从而在相似的场景下从一次运动到另一次运动实现液体平衡。在运动中随意饮水是否也能达到这种效果尚不清楚。我们描述了在重复的 1 小时运动期间随意饮水的可重复性，并研究了其随时间对液体平衡和选定的生理功能和知觉感觉的影响。12 名（3 名女性）健康个体参与了这项研究。他们每周进行 4 次 2×30 分钟的步行/慢跑运动（55%的 V˙O2，40°C，20-30%的相对湿度），中间穿插 3 分钟恢复期。在运动期间，参与者随意饮用（20°C）水。四次运动中，绝对水摄入量（1000 毫升/小时）、体重损失百分比（0.4%）、出汗率（1300 毫升/小时）和水摄入量替代的出汗损失百分比（80%）没有显著差异。心率、直肠温度以及口渴感和热应激感在第一次和第四次运动之间没有显著差异。与第一次运动相比，第四次运动时的主观用力程度显著降低，但差异很小（<1 个任意单位）。总之，在热环境中进行的四个连续的 1 小时步行/慢跑运动期间随意饮水，将导致相似的水摄入量和液体平衡、心率、直肠温度以及口渴感、热应激和用力程度的变化。
