Hemodynamic response to submaximal exercise after dehydration and rehydration in high school wrestlers

Cardiac output (Q), heart rate (HR), stoke volume (SV), and arteriovenous oxygen difference (AVD) were measured in 16 high school wrestlers during submaximal work (65%Vo2 Max) at normal weight (T1), after a four or five percent weight loss (T2), and following one hour of rehydration (T3). Weight losses were accomplished over 48 hours by fluid and food restriction as well as intermittent exercise. An ad libitum volume and commercial glucose-electrolyte solution was used to rehydrate the subjects. At T2 the mean weight loss was 4.6%, with the average plasma deficit estimated to be 4.9%. Under these conditions significantly higher HR and lower SV were observed during standardized exercise. Although Q was 7.8% lower and AVD was 7.3% higher after dehydration, neither change was statistically significant. Following rehydration all dependent variables returned to near T1 levels. It was concluded that despite a short rehydration period, the cardiovascular dynamics of these high school wrestlers rapidly returned to normal during moderately heavy work because of the small plasma changes that accompanied the 48-hour weight loss.