Plasma Volume Changes in Middle-Aged Male and Female Subjects during Marathon Running.

摘要

Circulatory fluid shifts were studied in middle-aged runners (six men and five women) during a 42.2 km marathon race. At 6 km body weight loss averaged less than 1% while plasma volume had reached 3.2% in men and 2.9% in women, but PV in both groups remained stable. Sweat rates during the race averaged 545 and 429 g/sq m/hr for men and women, respectively, with ad lib. water intake replacing 21-72 % of fluid loss. Increases in plasma protein concentration throughout the race reflected the observed initial decrease in PV. The ability to maintain stable PV can be explained in part by relationships among oncotic and hydrostatic pressures in the intra- and extra-vascular fluid compartments.