INFLUENCE OF ENVIRONMENTAL TEMPERATURE AND POSTURE ON VOLUME AND COMPOSITION OF BLOOD

Abstract

Values for blood vol. (by CO), Hb concn., protein concn., and hematocrit were obtained on 2 young men who lived for periods of about 10 days in a controlled temp. room. The room was maintained uncomfortably warm (91 [degree]F, D.B.; 82 [degree]F, W.B.) during part of each of the 2 expts. performed and uncomfortably cold (69[degree]F, D.B.; 60[degree]F, W.B.) during the remainder of the periods. The influence of bodily posture on vol. and composition of circulating blood was also studied in connection with these expts. on the effects of environmental temp. Hb and plasma protein conens. were less in the heat than in the cold. The quantity of circulating Hb was not influenced by exposure to either environmental extreme. However, plasma protein increased progressively in amt. during the first few days of exposure to heat and decreased somewhat more rapidly on exposure to cold. In addition to the well-known effects of bodily posture on the concn. of the blood, there was observed a progressive increase in amt. of circulating plasma protein during maintenance of the erect posture and a progressive decrease during recumbency. A detectable change in amt. of circulating Hb was not observed in these postural expts. which lasted several hrs.