McConell G K, Burge C M, Skinner S L, Hargreaves M
Department of Physiology, University of Melbourne, Parkville, Victoria, Australia.
Acta Physiol Scand. 1997 Jun;160(2):149-56. doi: 10.1046/j.1365-201X.1997.00139.x.
The effect of different rates of fluid ingestion on heart rate, rectal temperature, plasma electrolytes, hormones and performance was examined during prolonged strenuous exercise conducted at 21 degrees C. Seven well-trained males (24 +/- 1 yr; 68.6 +/- 2.9 kg; VO2 peak = 4.69 +/- 0.17 L min-1; mean +/- SEM) cycled for 2 h at 69 +/- 1% VO2 peak while receiving either no fluid replacement (NF), a volume of water estimated to prevent body weight loss (FR-100 = 2.32 +/- 0.10 L 2 h-1) or 50% of this volume (FR-60 = 1.16 +/- 0.05 L 2 h-1). The 2-h exercise bout was followed by a ride to exhaustion at a workload estimated to be 90% VO2 peak. After 2 h of exercise, NF was associated with a 3.2 +/- 0.1% weight loss, while FR-50 and FR-100 resulted in losses of 1.8 +/- 0.1 and 0.1 +/- 0.1%, respectively. Compared with FR-100, heart rate and rectal temperature were elevated (P < 0.05) during the second hour of exercise in NF, with FR-50 intermediate. Reductions in plasma volume during exercise were greater in NF and FR-50, compared with FR-100 and plasma sodium concentration was elevated in NF, decreased slightly in FR-100, with FR-50 intermediate. Plasma renin activity, aldosterone and atrial natriuretic peptide increased to similar extents in the three trials. Plasma vasopressin remained unchanged for FR-100, increased for NF, with intermediate values for FR-50. Exercise time to exhaustion at 90% VO2-peak was longer in FR-100 (328 +/- 93 s) than NF (171 +/- 75 s) with FR-50 (248 +/- 107 s) not significantly different from either FR-100 or NF. In conclusion, the responses of heart rate, rectal temperature, plasma sodium, and vasopressin during, and performance following, prolonged cycling exercise conducted at 21 degrees C are related to the amount of fluid ingested (i.e. the degree of dehydration).
在21摄氏度下进行长时间剧烈运动期间，研究了不同补液速率对心率、直肠温度、血浆电解质、激素及运动表现的影响。七名训练有素的男性（24±1岁；68.6±2.9千克；最大摄氧量=4.69±0.17升/分钟；均值±标准误）在以69±1%最大摄氧量的强度骑行2小时期间，分别接受无补液（NF）、估计可防止体重减轻的水量（FR-100 = 2.32±0.10升/2小时）或该水量的50%（FR-60 = 1.16±0.05升/2小时）。2小时的运动时段后，接着以估计为90%最大摄氧量的工作量骑行至力竭。运动2小时后，NF组体重减轻3.2±0.1%，而FR-50组和FR-100组分别减轻1.8±0.1%和0.1±0.1%。与FR-100相比，NF组在运动第二小时心率和直肠温度升高（P<0.05），FR-50组处于中间水平。与FR-100相比，NF组和FR-50组运动期间血浆量减少更多，NF组血浆钠浓度升高，FR-100组略有下降，FR-50组处于中间水平。三项试验中血浆肾素活性、醛固酮和心钠素升高程度相似。FR-100组血浆血管加压素保持不变，NF组升高，FR-50组处于中间值。在90%最大摄氧量时，FR-100组运动至力竭的时间（328±93秒）长于NF组（171±75秒），FR-50组（248±107秒）与FR-100组或NF组无显著差异。总之，在21摄氏度下进行长时间骑行运动期间及之后，心率、直肠温度、血浆钠和血管加压素的反应以及运动表现与补液量（即脱水程度）有关。
