Home-based lower leg heat therapy in postmenopausal women with hypertension. I. Effects on blood pressure

Despite conventional drug treatment for hypertension, postmenopausal women in the U.S. maintain relatively poor blood pressure (BP) control rates. Alternatives, such as heat therapy, represent promising adjuvant treatments that may reduce BP. This study tested the hypothesis that 8-weeks of home-based, lower leg heating would induce acute BP reductions that may contribute to sustained BP lowering in postmenopausal women with hypertension. Fifty-nine participants completed a randomized trial to receive either a thermoneutral sham (i.e., sham; 35 °C; n=30, 69±5y) or heat therapy (42 °C; n=29, 69±5y). Participants completed 8-weeks of home-based, lower leg water immersion (≈4 sessions/week; 45 min/session). Acute BP responses were assessed pre-to-post immersion, while pre-to-post intervention BPs were assessed using 24-hour ambulatory monitoring. The average acute reductions in BP and increases in heart rate pre-to-post immersion were greater in heat therapy (sham, systolic: -2±4mmHg, diastolic: -2±2mmHg, heart rate: -3±3bpm; heat therapy, systolic: -6±6mmHg, diastolic: -5±3mmHg, heart rate: 5±4bpm; all P<0.01). However, these acute responses did not translate into significant reductions in ambulatory BP, whereby ΔBP did not differ between groups (sham, systolic: 0±8mmHg, diastolic: 1±5mmHg; heat therapy, systolic: 2±8mmHg, diastolic: 1±5mmHg; all P≥0.412). Our data demonstrate that 8-weeks of home-based lower leg heat therapy reduces BP acutely, but was not associated with a chronic BP lowering effect in postmenopausal women with hypertension. Therefore, these findings suggest that home-based lower leg heat therapy is insufficient to elicit sustained BP reductions, despite consistent acute BP reductions, in postmenopausal women with either treated or untreated, hypertension.