Whole-body vibration exercise therapy improves cardiac autonomic function and blood pressure in obese pre- and stage 1 hypertensive postmenopausal women

Objective: Whole-body vibration (WBV) is an unconventional exercise therapy that appears to provide the same benefits of resistance training in postmenopausal women while being more safe and gentle on the joints. This study evaluated the effect of an 8-week WBV exercise regimen on heart rate variability (HRV) and blood pressure (BP) in obese postmenopausal women. Design: Randomized controlled study with two parallel groups. Participants: Twenty-five (age 50-65 years) obese (body-mass index >30 and <40 kg/m²) postmenopausal women. Intervention: Participants were randomly assigned to a WBV training group or nonexercising control group. Participants in the WBV group completed the supervised training 3 times a week. WBV training consisted of four static and four dynamic leg exercises (normal, high, and wide-stance squats and calf-raises) with vertical vibration (25-40 Hz and low-high amplitude) progressed throughout the 8 weeks. Outcome measures: Brachial systolic BP (SBP) and diastolic BP (DBP) and HRV: Sympathovagal balance (natural logarithm of low frequency [LnLF]/natural logarithm of high frequency [LnHF]; normalized low frequency [nLF]/normalized high frequency [nHF]), parasympathetic tone (LnHF, nHF, natural logarithm of root mean square of successive differences [LnRMSSD]), sympathetic tone (LnLF, nLF), natural logarithm of total power, and heart rate (HR). Results: There were significant group × time interactions (p < 0.05) for brachial SBP, DBP, LnLF/LnHF, and nLF/nHF that significantly decreased (p < 0.01) after WBV, compared with no changes after control. There was a significant (p < 0.05) increase in nHF and decrease in nLF in the WBV group compared with baseline, yet the changes were not different than those in the control group. No significant changes were observed in LnTP, LnLF, LnHF, LnRMSSD, or HR after 8 weeks in either group. Conclusions: WBV training for 8 weeks is an adequate unconventional exercise intervention for improving sympathovagal balance and BP in previously sedentary obese postmenopausal women.