Baroreceptor and Chemoreceptor Reflex Contribution in Cardiovascular Changes during Exercise

During exercise, both baroreceptors and chemoreceptors contribute in bringing about the cardiovascular changes, but less is documented about the contribution made by either of these mechanisms. The purpose of the present study was to demonstrate the differential effects of baroreceptors and chemoreceptors on cardiovascular parameters during exercise. Twelve healthy individuals were subjected to exercise maneuver on stationary cycling machine. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and electrocardiogram (ECG) were recorded during rest and immediately after exercise. Heart rate (HR) and heart rate variability (HRV) was computed from ECG. SBP, DBP, mean arterial blood pressure (MABP) and HR significantly increased due to exercise. Increase in SBP, DBP, Pulse pressure (PP), MABP and HR were more pronounced when chemoreceptor influence was not considered as against when changes due to both baroreceptors and chemoreceptors were considered. The HRV analysis reflected increase in the low-frequency (LF) power % and decrease in high-frequency (HF) power % along with reduction in LF/HF ratio due to exercise, but these changes were statistically not significant. Baroreceptors through baroreflex mechanism overall increase the CVS parameters. The novel finding in this study was the opposing action of chemoreceptor mechanism to that of baroreceptor mechanism in cardiovascular homeostasis during exercise.