Polycythemia and Hydration Status: Effects on Blood Volume and Thermoregulation during Exercise-Heat Stress,
Abstract
We studied the effects of autologous erythrocyte reinfusion on blood volume and thermoregulation during exercise in the heat. Five heat-acclimated males attempted four Heat Stress Tests (HSTs): two pre- and two post-reinfusion. Autologous erythrocyte reinfusion was accomplished with 500 ml of a NaC1-glucose-phosphate solution containing about 60% hematocrit. Both pre- and post-reinfusion on e HST was done while euhydrated and one HST was done while hypohydrated (-5% of body weight). After 30 min of rest in a 20 C antechamber, the HST consisted of a 120-min exposure (2 repeats of 15 min rest and 45 min walking) in a hot (35 deg C, 45%rh) environment. The following new findings were made concerning acute polycythemia in heat-acclimated subjects: (1) the increased erythrocyte volume was associated with a small plasma volume expansion; (2) the plasma volume expansion was associated with an increased total circulating protein mass; (3) the increased total circulating protein mass defends plasma volume when hypohydrated; (4) polycythemia increased sweating rate and reduced core temperature during exercise-heat stress; and (5) this thermoregulatory advantage conferred by acute polycythemia was effective even during hypohydration. Additionally, observations were made providing evidence that heat acclimation may increase extravascular protein mass.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1987
- Accession Number
- ADA185946
Entities
People
- Andrew J Young
- Kent B. Pandolf
- Michael N. Sawka
- Richard R. Gonzalez
- Stephen R. Muza
Organizations
- Boston University