Restoration of Plasma Volume after 16 Days of HeaD-Down Tilt Induced by a SingleBout of Maximal Exercise

摘要

Restoration of plasma volume after 16 days of head-down tilt induced by a singlebout of maximal exercise. Am. J. Physiol. 270 (Regulatory Integrative Comp. Physiol. 39): R3-R10, 1996. Seven healthy men performed maximal exercise 24 h before the end of 16 days exposure to 60 head-down tilt (HDT) to test the hypothesis that such an exercise technique could restore plasma volume (PV) at the end of a simulated space mission. Exercise consisted of supine cycling with graded work rates increasing by 16 W/min to volitional fatigue and required an average of 16 min. The experimental protocol was a standard cross-over design in which the order of treatment (exercise or control) was counterbalanced across all seven subjects. PV, fluid intake (ad libitum), urine output, renal function, and hormones associated with fluid homeostasis were measured before HDT, 24 h before the end of HDT just prior to exercise, and at the end of HDT 24 h after exercise. HDT reduced PV by 16% in both control and exercise conditions. Maximal exercise