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Polycythemia and hydration: effects on thermoregulation and blood volume during exercise-heat stress.
Am J Physiol. 1988 Sep; 255(3 Pt 2):R456-63.AJ

Abstract

We studied the effects of autologous erythrocyte infusion on thermoregulation and blood volume during exercise in the heat. Specifically, we wanted to determine whether heat-acclimated subjects, as well as hypohydrated subjects, would have a thermoregulatory advantage from acute polycythemia during exercise in the heat. Five heat-acclimated males attempted four heat stress tests (HSTs): two pre- and two postinfusion. Autologous erythrocyte infusion was accomplished with 500 ml of a NaCl-glucose-phosphate solution containing approximately 60% hematocrit. One HST, both pre- and postinfusion, was done while subjects were euhydrated, and one HST was done while subjects were hypohydrated (-5% of body wt). After 30 min of rest in a 20 degrees C antechamber, the HST consisted of a 120-min exposure (2 repeats of 15 min rest and 45 min walking) in a hot (35 degrees C, 45% relative humidity) environment. The findings concerning acute polycythemia in heat-acclimated subjects are summarized: 1) polycythemia increased (P less than 0.05) sweating rate and reduced (P less than 0.01) core temperature during exercise-heat stress for both euhydrated and hypohydrated subjects; 2) the erythrocyte infusion caused an increased (P less than 0.05) plasma volume and increased (P less than 0.01) blood volume; 3) the increased plasma volume was associated with an increased (P less than 0.05) total circulating protein mass; 4) the increased total circulating protein mass tended to better maintain plasma volume when hypohydrated; and 5) heat acclimation may increase extravascular protein mass. Therefore, it is concluded that erythrocyte infusion provides a thermoregulatory advantage during exercise in the heat for heat acclimated subjects when both euhydrated and hypohydrated.

Authors+Show Affiliations

US Army Research Institute of Environmental Medicine, Natick 01760-5007.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

3414840

Citation

Sawka, M N., et al. "Polycythemia and Hydration: Effects On Thermoregulation and Blood Volume During Exercise-heat Stress." The American Journal of Physiology, vol. 255, no. 3 Pt 2, 1988, pp. R456-63.
Sawka MN, Gonzalez RR, Young AJ, et al. Polycythemia and hydration: effects on thermoregulation and blood volume during exercise-heat stress. Am J Physiol. 1988;255(3 Pt 2):R456-63.
Sawka, M. N., Gonzalez, R. R., Young, A. J., Muza, S. R., Pandolf, K. B., Latzka, W. A., Dennis, R. C., & Valeri, C. R. (1988). Polycythemia and hydration: effects on thermoregulation and blood volume during exercise-heat stress. The American Journal of Physiology, 255(3 Pt 2), R456-63.
Sawka MN, et al. Polycythemia and Hydration: Effects On Thermoregulation and Blood Volume During Exercise-heat Stress. Am J Physiol. 1988;255(3 Pt 2):R456-63. PubMed PMID: 3414840.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Polycythemia and hydration: effects on thermoregulation and blood volume during exercise-heat stress. AU - Sawka,M N, AU - Gonzalez,R R, AU - Young,A J, AU - Muza,S R, AU - Pandolf,K B, AU - Latzka,W A, AU - Dennis,R C, AU - Valeri,C R, PY - 1988/9/1/pubmed PY - 1988/9/1/medline PY - 1988/9/1/entrez SP - R456 EP - 63 JF - The American journal of physiology JO - Am J Physiol VL - 255 IS - 3 Pt 2 N2 - We studied the effects of autologous erythrocyte infusion on thermoregulation and blood volume during exercise in the heat. Specifically, we wanted to determine whether heat-acclimated subjects, as well as hypohydrated subjects, would have a thermoregulatory advantage from acute polycythemia during exercise in the heat. Five heat-acclimated males attempted four heat stress tests (HSTs): two pre- and two postinfusion. Autologous erythrocyte infusion was accomplished with 500 ml of a NaCl-glucose-phosphate solution containing approximately 60% hematocrit. One HST, both pre- and postinfusion, was done while subjects were euhydrated, and one HST was done while subjects were hypohydrated (-5% of body wt). After 30 min of rest in a 20 degrees C antechamber, the HST consisted of a 120-min exposure (2 repeats of 15 min rest and 45 min walking) in a hot (35 degrees C, 45% relative humidity) environment. The findings concerning acute polycythemia in heat-acclimated subjects are summarized: 1) polycythemia increased (P less than 0.05) sweating rate and reduced (P less than 0.01) core temperature during exercise-heat stress for both euhydrated and hypohydrated subjects; 2) the erythrocyte infusion caused an increased (P less than 0.05) plasma volume and increased (P less than 0.01) blood volume; 3) the increased plasma volume was associated with an increased (P less than 0.05) total circulating protein mass; 4) the increased total circulating protein mass tended to better maintain plasma volume when hypohydrated; and 5) heat acclimation may increase extravascular protein mass. Therefore, it is concluded that erythrocyte infusion provides a thermoregulatory advantage during exercise in the heat for heat acclimated subjects when both euhydrated and hypohydrated. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/3414840/Polycythemia_and_hydration:_effects_on_thermoregulation_and_blood_volume_during_exercise_heat_stress_ L2 - https://journals.physiology.org/doi/10.1152/ajpregu.1988.255.3.R456?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -