Adams William M, Scarneo-Miller Samantha E, Vandermark Lesley W, Belval Luke N, DiStefano Lindsay J, Lee Elaine C, Armstrong Lawrence E, Casa Douglas J
Department of Kinesiology, University of North Carolina at Greensboro.
Korey Stringer Institute, University of Connecticut, Storrs.
J Athl Train. 2021 Feb 1;56(2):203-210. doi: 10.4085/1062-6050-0436.19.
Hypohydration has been shown to alter neuromuscular function. However, the longevity of these impairments remains unclear.
To examine the effects of graded exercise-induced dehydration on neuromuscular control 24 hours after exercise-induced hypohydration.
Crossover study.
Laboratory.
A total of 23 men (age = 21 ± 2 years, height = 179.8 ± 6.4 cm, mass = 75.24 ± 7.93 kg, maximal oxygen uptake [VO2max] = 51.7 ± 5.5 mL·kg-1·min-1, body fat = 14.2% ± 4.6%).
INTERVENTION(S): Participants completed 3 randomized exercise trials: euhydrated arrival plus fluid replacement (EUR), euhydrated arrival plus no fluid (EUD), and hypohydrated arrival plus no fluid (HYD) in hot conditions (ambient temperature = 35.2°C ± 0.6°C, relative humidity = 31.3% ± 2.5%). Each trial consisted of 180 minutes of exercise (six 30-minute cycles: 8 minutes at 40% VO2max; 8 minutes, 60% VO2max; 8 minutes, 40% VO2max; 6 minutes, passive rest) followed by 60 minutes of passive recovery.
MAIN OUTCOME MEASURE(S): We used the Landing Error Scoring System and Balance Error Scoring System (BESS) to measure movement technique and postural control at pre-exercise, postexercise and passive rest (POSTEX), and 24 hours postexercise (POST24). Differences were assessed using separate mixed-design (trial × time) repeated-measures analyses of variance.
The magnitude of hypohydration at POSTEX was different among EUR, EUD, and HYD trials (0.2% ± 1%, 3.5% ± 1%, and 5% ± 0.9%, respectively; P < .05). We observed no differences in Landing Error Scoring System scores at pre-exercise (2.9 ± 1.6, 3.0 ± 2.1, 3.0 ± 2.0), POSTEX (3.3 ± 1.5, 3.0 ± 2.0, 3.1 ± 1.9), or POST24 (3.3 ± 1.9, 3.2 ± 1.4, 3.3 ± 1.6) among the EUD, EUR, and HYD trials, respectively (P = .90). Hydration status did not affect BESS scores (P = .11), but BESS scores at POSTEX (10.4 ± 1.1) were greater than at POST24 (7.7 ± 0.9; P = .03).
Whereas exercise-induced dehydration up to 5% body mass did not impair movement technique or postural control 24 hours after a prolonged bout of exercise in a hot environment, postural control was impaired at 60 minutes after prolonged exercise in the heat. Consideration of the length of recovery time between bouts of exercise in hot environments is warranted.
已有研究表明，轻度脱水会改变神经肌肉功能。然而，这些损伤的持续时间尚不清楚。
研究分级运动诱导的脱水对运动诱导的轻度脱水24小时后神经肌肉控制的影响。
交叉研究。
实验室。
共23名男性（年龄=21±2岁，身高=179.8±6.4厘米，体重=75.24±7.93千克，最大摄氧量[VO2max]=51.7±5.5毫升·千克-1·分钟-1，体脂率=14.2%±4.6%）。
参与者在炎热环境（环境温度=35.2°C±0.6°C，相对湿度=31.3%±2.5%）下完成3项随机运动试验：正常水合状态到达并补充液体（EUR）、正常水合状态到达但不补充液体（EUD）以及轻度脱水状态到达且不补充液体（HYD）。每项试验包括180分钟的运动（六个30分钟周期：40%VO2max强度下运动8分钟；60%VO2max强度下运动8分钟；40%VO2max强度下运动8分钟；6分钟被动休息），随后进行60分钟的被动恢复。
我们使用落地误差评分系统和平衡误差评分系统（BESS）在运动前、运动后和被动休息（POSTEX）以及运动后24小时（POST24）测量运动技术和姿势控制。使用单独的混合设计（试验×时间）重复测量方差分析评估差异。
EUR、EUD和HYD试验在运动后（POSTEX）的脱水程度不同（分别为0.2%±1%、3.5%±1%和5%±0.9%；P<.05）。在EUD、EUR和HYD试验中，运动前（2.9±1.6、3.0±2.1、3.0±2.0）、运动后（POSTEX，3.3±1.5、3.0±2.0、3.1±1.9）或运动后24小时（POST24，3.3±1.9、3.2±1.4、3.3±1.6）的落地误差评分系统得分均无差异（P=.90）。水合状态不影响BESS得分（P=.11），但运动后（POSTEX）的BESS得分（10.4±1.1）高于运动后24小时（7.7±0.9；P=.03）。
在炎热环境中进行长时间运动后24小时，高达5%体重的运动诱导脱水并未损害运动技术或姿势控制，但在炎热环境中长时间运动60分钟后姿势控制受损。在炎热环境中运动时，有必要考虑运动间歇的恢复时间长度。
