Vagal control of heart rate is increased during post‐exercise recovery

Abstract

Increases in exercise intensity are known to reset, in an upward and rightward direction, the arterial baroreflex (ABR) control of heart rate (HR) and mean arterial pressure (MAP). ABR function during recovery from exercise has not been extensively studied and therefore is unreported in the literature. We hypothesized that carotid baroreflex (CBR) function curves would recover with a trend opposite to the original intensity related resetting following exercise. To test this hypothesis, healthy young subjects performed cycling exercise at two workloads to establish HRs of 120 and 150 bpm. CBR function curves were collected using the neck pressure/neck suction technique. An increase in HR during recovery vs. rest (p=0.032) was recorded in all subjects without a change in MAP. From rest to recovery there were significant increases in the response range (RR) of HR (p=0.029) and the sensitivity or gain of the ABR function curves (p=0.036). The increase in HR without an increase in MAP was expected, but the RR increase during recovery due to an increase in threshold without a concomitant increase in saturation point was not. It is concluded that vagal control of HR during recovery from exercise is increased without a change in the CBR control of blood pressure.Supported by a TACSM SRDA.