Regular aerobic exercise modulates age-associated declines in cardiovagal baroreflex sensitivity in healthy men

1. Cardiovagal baroreflex sensitivity (BRS), the arterial baroreflex-mediat ed change in the R-R interval per unit change in systolic blood pressure, d ecreases with advancing age in sedentary adult humans. We determined the ef fects of regular aerobic exercise on the age-related decline in cardiovagal BRS. 2. In the cross-sectional study, 133 healthy men 18-79 years of age who wer e either sedentary performing moderate aerobic exercise, or endurance exerc ise trained were studied. Among the sedentary men, cardiovagal BRS (phase I V of Valsalva's manoeuvre) was progressively lower (P < 0.05) in the middle -aged (<similar to>33%) and older (similar to 60%) groups compared with the young group. In contrast, cardiovagal BRS was similar in the young and mid dle-aged men in the moderate exercise and endurance-trained groups. Cardiov agal BRS was lower (P < 0.05) in the older exercising men, but the magnitud e of decline across age (<similar to>30%) was only half as great as that in sedentary men. Cardiovagal BRS was 40-75% greater (P < 0.05) in middle-age d and older men who exercised regularly compared with their sedentary peers . 3. In the intervention study, a 3 month aerobic exercise intervention (prim arily walking) increased cardiovagal BRS by an average of 25% (P < 0.05) in 13 previously sedentary middle-aged and older (56 +/- 1 years) healthy men . 4. Our results demonstrate for the first time that regular aerobic exercise : (1) attenuates the age-associated decline in cardiovagal BRS; and (2) par tially restores the loss of cardiovagal BRS in previously sedentary middle- aged and older healthy men.