HORMONAL ALTERATIONS IN MEN EXPOSED TO HEAT AND COLD STRESS

Abstract

Three healthy, white males were exposed successively, after a preliminary 2-week period of physical conditioning, to 19 5.25-hr. periods of heat (107[degree]F, dry bulb, 89[degree]F, wet bulb); to 14 5-hr. periods of cold (-20[degree]F); to 5 re-exposures to heat; to a 5-week interval of no exposure to environmental stress or rigorous exercise; and finally, to 3 re-exposures to heat. Measurements of circulating eosinophiles, absolute lymphocytes, urinary uric acid-creatinine ratio, 24-hr. 17-ketosteroid excretion, and admn. of adrenocorticotropic hormone (ACTH) were used to evaluate adrenal cortical responses. Basal metabolic rates were used as an index of thyroid activity. A semi-micromethod for 17-ketosteroid analy-ysis was established using diethyl ether extraction in place of the more laborious CCl4 technique. The number of circulating eosinophiles, was significantly reduced in daily counts during exercise, a combination of heat and exercise, and a combination of cold and exercise, as compared to a baseline period without stress. There was no significant difference in the excretion of 17-ketos-teroids in any of the exptl. periods. This was also true of the daily urinary uric acid-creatinine ratio, and absolute lymphocyte count. The admn. of ACTH yielded the same pattern of response after heat and cold stress as after control expts. indicating that this method is not sensitive enough for this type of study. There was no significant change in basal metabolic rate throughout the exptl. period.