Seasonal Fluctuations in Blood Volume

Abstract

The plasma volume was measured by T1824 dilution in groups of normal young male subjects at regular intervals over the course of 3 years. The plasma volume increased during the summer and decreased during the winter, but this change was variable from subject to subject and was not as marked during 1 year as during the other 2. Ascorbic acid in daily supplement of 400 mg., taken during the first year of the study, did not influence the plasma volume fluctuations. The red blood cell mass, circulating haemoglobin, and total circulating plasma protein varied in the same way and the mean corpuscular haemoglobin concentration also increased during the summer in 2 of the 3 years. The changes in plasma volume are attributed to the influence of environmental temperature and indicate some degree of seasonal acclimatization. Serial measurements of total body water and extracellular space on a few subjects suggest that the seasonal fluctuation affects mainly the vascular system.

Iron Status of Young Males and Females Performing Weight-Training Exercise

“…A plasma volume change due to seasonal variation is the most likely explanation for the observed decline in hemoglobin concentration. Resting plasma volume levels have been shown to undergo seasonal variation and reach peak levels during the summer months (7). In the present study, plasma volume increased to a significantly greater extent in the summer (9.7%) than in the fall (2.5%).…”

Studies of I131-Albumin Catabolism and Distribution in Normal Young Male Adults*

“…and the error of the method determined (76). However, with two exceptions (74,77), there is a paucity of published data regarding the variability of serial plasma volumes determined with labeled albumin in normal subjects over long intervals. Care was taken in this study to avoid the recognizable errors (78, 79).…”

Variations in the hematological parameters of shrews

“…D e b & Hart (1956) observed a decrease in M CHC in rats k e p t in low tem p eratu res. A decrease in M CHC in w in ter w as also observed in hum ans (Doupe, Ferguson & Hildes, 1957). Sealander (1966) found an inversely proportional relatio n in C lethrionom ys ru tilu s betw een M CHC and a ir tem p e ra tu re , w ith the exception of J a n u a ry and F eb ru ary , w hen this index d istin ctly decreased.…”