Morgan R M, Patterson M J, Nimmo M A
Strathclyde Institute for Biomedical Sciences, University of Strathclyde, Glasgow, UK.
Acta Physiol Scand. 2004 Sep;182(1):37-43. doi: 10.1111/j.1365-201X.2004.01305.x.
To determine whether acute exercise-heat-induced dehydration affects sweat composition, eight males cycled for 2 h at 39.5 +/- 1.6% VO2peak on two separate occasions in a hot-humid environment (38.0 +/- 0.0 degrees C, 60.0 +/- 0.1% relative humidity).
During exercise, subjects ingested either no fluid (dehydration) or a 20 mmol L(-1) sodium chloride solution (euhydration). The volume of solution, calculated from whole-body sweat loss and determined in a familiarization trial, was ingested at 0 min and every 15 min thereafter. Venous blood was collected at 0, 60 and 120 min of exercise and sweat was aspirated from a patch located on the dominant forearm at 120 min.
Following the 2-h cycling exercise, sweat [Na+] and [Cl-] was greater (P < 0.05) in the dehydration trial (Na+ 91.1 +/- 6.8 mmol L(-1); Cl- 73.3 +/- 3.5 mmol L(-1)) compared with the euhydration trial (Na+ 81.1 +/- 5.9 mmol L(-1); Cl- 68.5 +/- 3.3 mmol L(-1)). In addition, dehydration invoked a greater serum [Na+] (142.2 +/- 0.7 mmol L(-1); P < 0.05), [Cl-] (105.8 +/- 0.6 mmol L(-1); P < 0.05) and [K+] (5.27 +/- 0.2 mmol L(-1); P < 0.05) over the euhydration values for [Na+], [Cl-] and [K+], respectively (138.9 +/- 0.6, 102.9 +/- 0.5 and 4.88 +/- 0.1 mmol L(-1)). Plasma aldosterone was also significantly higher during exercise in the dehydration trial compared with the euhydration trial (53.8 +/- 3.8 vs. 40.0 +/- 4.3 ng dL(-1); P < 0.05).
Acute exercise-heat stress without fluid replacement resulted in a greater sweat [Na+] and [Cl-] which was potentially related to greater extracellular fluid [Na+], plasma aldosterone or sympathetic nervous activity.
为了确定急性运动热诱导的脱水是否会影响汗液成分，八名男性在炎热潮湿环境（38.0±0.0℃，相对湿度60.0±0.1%）中于两个不同场合以39.5±1.6%最大摄氧量进行了2小时的骑行。
运动期间，受试者要么不摄入液体（脱水），要么摄入20 mmol/L的氯化钠溶液（正常水合）。根据全身汗液流失量计算并在预试验中确定的溶液体积，在0分钟时摄入，此后每15分钟摄入一次。在运动的0、60和120分钟采集静脉血，并在120分钟时从优势前臂的贴片处抽吸汗液。
经过2小时的骑行运动后，与正常水合试验相比，脱水试验中的汗液[Na⁺]和[Cl⁻]更高（P<0.05）（Na⁺ 91.1±6.8 mmol/L；Cl⁻ 73.3±3.5 mmol/L），正常水合试验中Na⁺为81.1±5.9 mmol/L；Cl⁻为68.5±3.3 mmol/L）。此外，脱水导致血清[Na⁺]（142.2±0.7 mmol/L；P<0.05）、[Cl⁻]（105.8±0.6 mmol/L；P<0.05）和[K⁺]（5.27±0.② mmol/L；P<0.05）分别高于正常水合时的[Na⁺]、[Cl⁻]和[K⁺]值（138.9±0.6、102.9±0.5和4.88±0.1 mmol/L）。与正常水合试验相比，脱水试验中运动期间血浆醛固酮也显著更高（53.8±3.8对40.0±4.3 ng/dL；P<0.05）。
不补充液体的急性运动热应激导致汗液中[Na⁺]和[Cl⁻]更高，这可能与细胞外液[Na⁺]增加、血浆醛固酮或交感神经活动增强有关。
