Five untrained females having no history of heat exposure worked in a cool (16-20°C DB, 28% RH) environment on day 1 and a warm environment of day 2 (45°C DB, 28% RH). Work rate (bicycle ergometer) was 30% of individual VO2 max values and work time on both days was 45 min. Venous blood samples were obtained at rest, after 40 min of work and 25 min after work ceased. Analysis of blood samples indicated an 8.3% increase in HCT during work on D1, and a plasma volume reduction of 12.8% though total circulation protein increased 11.5%. Except for K+, all parameters approximated control values within 25 min post exercise. On D2, work in heat caused a 12% increase in HCT and a plasma volume reduction of 17.7%. Mean total protein did not significantly change from resting values. These data indicated that for a given % VO2 max, untrained females suffer greater reductions in plasma volumes than do exercised males. Similar to males, dilatation of the cutaneous vascular bed in unacclimatized females resulted in loss of protein from the vascular volume.
|Number of pages||11|
|Journal||Journal of Immunology|
|State||Published - Dec 1 1974|