Changes in Hematological Parameters Associated with multiple Cold Air Exposureand Triiodothyronine (T3) Supplement

摘要

Whole Blood hematocrit (HCT) decreases during cold acclimation (1). To betterunderstand this finding, we analyzed several hematological parameters before, during, and after a human cold acclimation protocol. Male volunteers were exposed to cold air (4 C), twice/day, 30 min/exposure, for a total of 80 exposures. Group A received placebo (n=8); Group B received triiodothyronine (T3) (30 mcg/day) (n=8). Blood was analyzed prior to and after every 20 exposures. Both groups reacted similarly. HCT decreased; mean corpuscular hemoglobin concentration (MCHC) and plasma volume (PV) increased; and red blood cells (RBC), hemoglobin (HGB), white blood cells (WBC), and mean corpuscular volume (MCV) were unchanged after cold exposure. Since HCT measured by centrifugation and Coulter counter calculations were similarly decreased, there was no apparent change in the deformability of the RBC with cold exposure. The increased MCHC observed during cold exposure may be attributed to a RBC subpopulation with a slightly smaller MCV to account for the lower HCT and increased PV. (jes)