The Combined Effects of Exercise and Post Dehydration Water Drinking on Plasma Argenine Vasopressin, Plasma Osmolality and Body Temperature in Healthy Males

The purpose of this study was to inves tigate the effect of exercise and post dehydration water drinking on varia tions in plasma arginine vasopressin (P A VP), plasma osmolality (Posm) and tympanic temperature (Ttym) in healthy males.

Materials and Methods: 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 V02 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 exer cise) were obtained through an indwelling ve nous cannula. Plasma concentrations for Na+, and AVP were determined. Posm was calculated using Na+ concentrations. Simultaneous varia tions in Ttym were also determined.

Results: Our results demonstrated a positive cor relation between increase in P A VP and both Posm and Ttym during exercise but not during the re covery period. When exercise was combined with water drinking a fast and significant sup pression in P A VP occurred (P<0.05). Conclusions: These results suggest that Posm and Ttym have no significant effect on AVP secretion post exercise, and thus other factors must be in volved in AVP secretion during post exercise re covery period.