Acute Albumin-Induced Plasma Volume Expansion and Exercise in the Heat: Effects on Hormonal Responses in Men.

摘要

To assess the responses of plasma hormones to acute expansion of plasma volume and exercise in the heat, 50 g of albumin or 200 ml saline was administered intravenously followed by exercise (40% VO sub 2 max) in the heat (45 C/20% rh). Blood samples were obtained after sitting in the heat for one hour, one hour after completion of infusion, after standing for 30 minutes, and 15, 30, 45 and 60 minutes after commencing exercise. While plasma cortisol was generally unaffected by these treatments, postural and exercise effects were manifested in the absence of the diurnal decrease that ordinarily occurs during the morning hours. Aldosterone levels were generally decreased and growth hormone levels were unaffected by albumin administration, while exercise in the heat resulted in an increase in both these hormones in the control and experimental groups. Angiotensin I levels were significantly decreased at several sampling intervals by albumin administration, but unaffected by exercise; however, vasopressin was unaffected by all experimental procedures. No correlations could be drawn between the intensity of these adaptational responses and the ability to complete the exercise protocol. (Author)