Lifelong Exercise Improves Cardiac Baroreflex Function But Not Dynamic Cerebral Autoregulation In Older Adults

Abstract

Previous studies suggest that aerobic exercise training improves cardiac baroreflex function. However, the effects of aerobic exercise training on dynamic cerebral autoregulation (dCA) are not clear. The purpose of this study was to determine the effect of lifelong exercise on cardiac baroreflex function and dCA in older adults. Eleven Masters athletes (MA) (8 males, age 73±6 yrs, aerobic training>15 yrs) and 9 healthy sedentary elderly (SE) (6 males, age 73±4 yrs) participated in this study. Blood pressure (BP), cerebral blood flow velocity (CBFV) and heart rate were measured continuously during resting conditions and repeated sitstand maneuvers. Baroreflex gain was assessed using transfer function analysis of spontaneous changes in systolic BP and RR‐interval in the low (0.05–0.15 Hz; LF) and high (0.15–0.35 Hz; HF) frequency ranges. dCA was assessed using transfer function analysis of induced changes in mean BP and CBFV during repeated sit‐stand maneuvers at 0.05 Hz (10s sit, 10s stand). MA showed higher cardiac baroreflex gain compared to SE (LF: MA: 7.69±7.95, SE: 3.13±1.22, ms/mmHg, P=0.001, HF: MA: 11.13±7.33, SE: 4.11±2.70, ms/mmHg, P=0.006). However, dCA was similar between the two groups (normalized gain: MA: 1.50±0.56, SE: 1.42±0.40, %CBFV/mmHg, P=0.743). These findings suggest that lifelong exercise improves cardiac baroreflex function, but does not alter dCA in older adults.