Physical Activity Reduces Blood Pressure Load Indices in African- American Women

Abstract

0688 The prevalence of hypertension is disproportionate among African-American women compared to Caucasians with the greatest disparity in incidence occurring at younger ages. Although physical activity is recommended as first step therapy for the prevention and treatment of hypertension, the ideal physical activity profile (type, intensity, duration) to best achieve optimal blood pressure outcomes among hypertension-prone African-American women remains unclear given that physical activity must also be feasible for, and acceptable to, the target population. PURPOSE: This ongoing single-blinded, randomized, parallel-group study examines the effects of accumulated, lifestyle physical activity on blood pressure indices in sedentary, untreated mildly hypertensive African-American women aged 18–45. METHODS: Women (n = 5 to date) randomized to an 8-week intervention were instructed to engage in lifestyle compatible (e.g., walking, stair climbing) physical activity for 10-minutes, 3-times/day, 5-days/week at a prescribed heart rate corresponding to an intensity of 50 – 60% heart rate reserve. Women in the control group (n = 7 to date) continued with their usual activities. Mean changes in cuff, ambulatory, and pressure load (the percentage of daytime measurements >140/90 mmHg and nighttime >120/80 mmHg) were compared using paired t-tests. RESULTS: Greater reductions in cuff and ambulatory pressures were noted in the exercise group (daytime diastolic −4.8 mmHg vs −1.7 mmHg, respectively), although not statistically significant. Moreover, the exercise group showed greater reductions in most pressure load indices, a more sensitive marker, including a 39.8 % reduction in nighttime diastolic pressure load (p = .021). CONCLUSIONS: The accumulation of lifestyle physical activity appears to provide a reduction in pressure load even in the absence of a significant reduction in average cuff and ambulatory pressures in this sample. These findings may be clinically important given the strong correlation between pressure load and target organ damage, especially in African-Americans. Supported by NIH-K23NR00168