Effects of aerobic exercise training and yoga on the baroreflex in healthy elderly persons

It is unclear whether the age-associated reduction in baroreflex sensitivity is modifiable by exercise training. The effects of aerobic exercise training and yoga, a non-aerobic control intervention, on the baroreflex of elderly persons was determined. Baroreflex sensitivity was quantified by the alpha-index, at high frequency (HF; 0.15-0.35 Hz, reflecting parasympathetic activity) and mid-frequency (MF; 0.05-0.15 Hz, reflecting sympathetic activity as well), derived from spectral and cross-spectral analysis of spontaneous fluctuations in heart rate and blood pressure. Twenty-six (10 women) sedentary, healthy, normotensive elderly (mean 68 years, range 62-81 years) subjects were studied. Fourteen (4 women) of the sedentary elderly subjects completed 6 weeks of aerobic training, while the other 12 (6 women) subjects completed 6 weeks of yoga. Heart rate decreased following yoga (69 +/- 8 vs. 61 +/- 7 min(-1), P < 0.05) but not aerobic training (66 +/- 8 vs. 63 +/- 9 min(-1), P = 0.29). VO2 max increased by 11% following yoga (P < 0.01) and by 24% following aerobic training (P < 0.01). No significant change in alpha(MF) (6.5 +/- 3.5 vs. 6.2 +/- 3.0 ms mmHg(-1), P = 0.69) or alpha(HF) (6.5 +/- 4.7 vs. 8.9 +/- 3.5 ms mmHg(-1), P = 0.65) occurred after aerobic training. Following yoga, alpha(HF) (8.0 +/- 3.6 vs. 11.5 +/- 5.2 ms mmHg(-1), P < 0.01) but not alpha(MF) (6.5 +/- 3.0 vs. 7.6 +/- 2.8 ms mmHg(-1), P = 0.29) increased. Short-duration aerobic training does not modify the alpha-index at alpha(MF) or alpha(HF) in healthy normotensive elderly subjects. alpha(HF) but not alpha(MF) increased following yoga, suggesting that these parameters are measuring distinct aspects of the baroreflex that are separetly modifable.