Influence of Erythrocythemia on Blood Volume and Thermoregulation during Exercise-Heat Stress,
Abstract
We studied the effects of autologous erythrocyte infusion on blood volume and thermoregulation during exercise in the heat. Using a double blind design, nine unacclimated male subjects were infused with either 700 ml of a NaC1 glucose-phosphate solution containing a approx. 60% hematocrit (n=6, reinfusion) or 700 ml of this solution only (n=3, saline). A heat stress test (HST) was attempted approximately 2 wk pre-and 48 h post-infusion during the late spring months. After 30 min of rest in a 20 C antechamber, the HST consisted of a 120-min exposure (two repeats of 15-min rest and 45-min treadmill walking) in a hot (35c, 45% rh) environment while euhydrated. Red cell volume (RCV, 51 CR) and plasma volume (PV, 125I) were measured 24-h before each HST, and maximal oxygen uptake (VO2 max) was measured 24-h after each HST. Generally, no significant effects were found for the saline group. For the reinfusion group, RCV (11%, P<0.01) and V02 max (11%, P <0.05) increased after infusion, and the following observations were made: 1) the increased RCV was associated with a reduction in PV to maintain the same blood volume as during the preinfusion measurements; 2) erythrocythemia reduced total circulating protein, but did not alter F-cell ratio, plasma osmolality, plasma protein content, or plasma lactate at rest or during exercise-heat stress; (3) erythrocythemia did not change the volume of fluid entering the intravascular space from rest to exercise-heat stress; and 4) erythrocythemia reduced heat storage during exercise-heat stress.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1986
- Accession Number
- ADA165014
Entities
People
- Andrew J Young
- Michael N. Sawka
- Richard C. Dennis
- Richard R. Gonzalez
- Stephen R. Muza
Organizations
- United States Army Research Institute of Environmental Medicine