Comparison of basal plasma and blood volumes of Negro and white males

¹ Physiology Branch, Environmental Protection Research Division, Quartermaster Research and Engineering Command, U.S. Army, Quartermaster Research and Engineering Center, Natick, Massachusetts

Basal plasma and blood volumes of U.S. Negro soldiers were compared with those of white soldiers. Plasma volume (PV) was determined with T-1824; blood volume (BV) was calculated from PV and hematocrit. Both groups were matched with respect to height, weight, fatness-leanness and age; daily activity and diet were the same for all men for 2 weeks prior to measurements. The Negro group had significantly lower PV, BV and hemoglobin concentration than the white group. Hematocrits were the same for both groups. Mean values were (Negro vs. white): PV, 2.72 vs. 3.06 l.; BV, 5.05 vs. 5.71 l.; hematocrit, 46.2 vs. 46.5%; hemoglobin, 14.4 vs. 15.1 gm %. The limitations in attributing a significant role in cold or heat tolerance to differences in basal blood volume are discussed.