Influence of exercise training on heart rate variability in post-menopausal women with elevated arterial blood pressure

Low heart rate variability (HRV) has been reported to be an independent risk factor for the development of coronary heart disease in women and has recently been identified as a risk factor for cardiac sudden death and all‐cause mortality. We have recently demonstrated that endurance‐trained post‐menopausal women demonstrate higher levels of HRV than sedentary control subjects. The purpose of the present study was to test the hypothesis that 12 weeks of regular aerobic exercise would increase HRV in sedentary post‐menopausal women with elevated arterial blood pressure (BP) (i.e. either high normal BP or stage I hypertension). A secondary aim was to test the hypothesis that the increase in HRV with exercise training, if observed, would be associated with an increase in spontaneous cardiac baroreflex sensitivity (SBRS), an important physiological determinant of HRV. To accomplish these aims, we studied eight sedentary post‐menopausal women (age=54·5±1·3 years) before and after 12 weeks of aerobic exercise training (3·3±0·3 days per week at 70%±2% of maximal heart rate for 43±3 min per day). Maximal oxygen uptake and body weight did not change (P>0·05) with training, but percentage fat (35·5±2·6% vs. 34·5±2·3%, P0·05). SBRS was also not different before and after aerobic exercise training (1062 vs. 1363 ms mmHg−1 respectively, P>0·05). In contrast, systolic and diastolic BP were reduced approximately 8 and approximately 5 mmHg with training (both P