Augmented cardiopulmonary baroreflex control of forearm vascular resistance in young athletes.

Abstract

The aim of this study was to examine the effect of exercise training on reflex control of vascular resistance in human males. Forearm vascular responses to lower body negative pressure (LBNP) at -10 and -40 mm Hg were compared between highly trained young athletes (21.5 +/- 0.5 years old, n = 14) and age-matched nonathletes (20.7 +/- 0.5 years old, n = 16). Resting heart rate was lower in athletes than in nonathletes. Resting blood pressure, central venous pressure, forearm blood flow, and forearm vascular resistance were not different between the two groups. The magnitude of reflex forearm vasoconstriction in response to LBNP at -10 mm Hg, which decreased central venous pressure but did not alter blood pressure or heart rate, was greater in athletes than in nonathletes. The slope of the regression line relating changes in central venous pressure and forearm vascular resistance was steeper in athletes than in nonathletes. Vasoconstrictive responses to intraarterially administered norepinephrine and angiotensin II did not differ between athletes and nonathletes. These results suggest that the tonic inhibitory influence of the cardiopulmonary receptors is augmented in athletes. This augmentation may contribute to some of cardiovascular and endocrine adaptations that occur with exercise training.