Exercise training augments cardiopulmonary baroreflex control of forearm vascular resistance in middle-aged subjects.

Nine subjects (average age 56 +/- 7 years old) underwent sitting cycle ergometer exercise for four months. Exercise capacity and maximal VO2 increased after exercise training in these subjects. Forearm vascular responses to lower body negative pressure (LBNP) at -10 and -40 mmHg were compared before and after exercise training. The magnitude of reflex forearm vasoconstriction in response to LBNP at -10 mmHg was greater after exercise training than before. The decreases in central venous pressure during LBNP at -10 mmHg were similar before and after exercise training. The pressor and forearm vasoconstrictive responses to the cold pressor test also did not differ before and after exercise training. These results suggest that mild exercise training in middle-aged subjects augments the tonic inhibitory influence of the cardiopulmonary receptors on forearm vascular resistance.