Walking intensity as a hypotensive stimulus in postmenopausal women

Endurance exercise can be accompanied with reductions in blood pressure (BP), but the role of exercise intensity, or its effectiveness in postmenopausal (PM) women, is not clear. PURPOSE to determine whether walking, and its intensity, can lower BP, heart rate (HR), and affect their variability in PM women. METHODS A longitudinal study with 42 PM women, mean age 58 years and mean BMI 28.6 kg/m2, who walked 2.84 km/day, five days a week for 15 weeks at either a moderate or a high relative intensity. Target training intensity was either 95% or 125% of individual's ventilatory threshold (VT, intensity at which plasma acidification during transition from aerobic to anaerobic exercise triggers compensatory hyperventilation), but due to imperfect compliance, relative intensities ranged between 90 % and 134% of VT. BP was measured every 30 minutes for seven consecutive days before and after 15 weeks of training with an ambulatory HR-BP monitor (A & D Co, Tokyo, Japan). During HR-BP measurements subjects did not engage in training. Means and SDs as well as circadian double amplitudes of HR and BP were calculated after fitting the data to 24-h and 12-h cosinor curves. RESULTS Training intensity resulted in (1) significant proportional increase in aerobic capacity manifested as increase in VT (r = 0.658), and a non-significant trend toward a proportional decrease in (2) resting HR (r = −0.333), (3) SD of HR variability (r = −0.103), (4) BPdia (r = −0.269), (5) BPsys (r = −0.175), and (6) circadian double amplitude of BPsys (r = −0.296). (7) There was no influence of training intensity on exercise-induced tachycardia. CONCLUSION Intensities that can be generated through walking are not as effective for reduction of BP and HR as they are for increases in aerobic capacity in PM women. In addition, training effects were pleiotropic: some beneficial (1–2 and 4–6), some indifferent (7), and some detrimental (3) to cardiovascular health. Supported by NIH Grant M01 RR0042 to the UM General Clinical Research Center.