combined effects of exercise and post dehydration water drinking on plasma argenine vasopressin, plasma osmolality and body temperature in healthy males

ABSTRACT

The purpose of this study was to investigate the effect of exercise and post dehydration water drinking on variations in plasma arginine vasopressin [PAVP], plasma osmolality [Posm] and tympanic temperature [Ttym] in healthy males. Eight healthy young males [27.4 +/- 0.8 yrs old] volunteered for the study. They performed constant work exercise, at a rate of 60 rpm at 50% of individual work load for VO2 peak for 30 minutes. Six blood samples [at minutes 0, 15 and 30 during exercise and at minutes 3, 15 and 30 after termination of exercise] were obtained through an indwelling venous cannula. Plasma concentrations for Na+, and AVP were determined. Posm was calculated using Na+ concentrations. Simultaneous variations in Ttym were also determined. Our results demonstrated a positive correlation between increase in PAVP and both Posm and Ttym during exercise but not during the recovery period. When exercise was combined with water drinking a fast and significant suppression in PAVP occurred [P<0.05]. These results suggest that Posm and Ttym have no significant effect on AVP secretion post exercise, and thus other factors must be involved in AVP secretion during post exercise recovery period