Abstract P137: Examining the Effect of the Accumulation of Physical Activity on Blood Pressure in a Physical Activity Intervention for Community Dwelling Older Adults

Background: High blood pressure is one of the most common health conditions experienced by US older adults. Hypertension leads to heart disease, CVD incidence, stroke, and death. In older adults, community based physical activity (PA) interventions have been shown to significantly decrease systolic and diastolic blood pressure. The American Heart Association Physical Activity Guidelines recommend that adults accumulate at least 150 minutes of moderate-vigorous intensity physical activity (MVPA) per week in order to obtain substantial health benefits. It is not clear whether accumulation of total minutes of physical activity is more important for significant changes in cardiovascular health, including reductions in blood pressure levels, or whether the intensity of the physical activity is important. New physical activity assessment techniques allow us to assess daily minutes of intensity outside of the clinic environment. Study Objectives: The objective of this study was to assess the effects of total accumulation of PA, independent of time spent in MVPA, on changes in blood pressure in older adults participating in a 6-month physical activity intervention. Methods: Study data are from a multilevel physical activity intervention (MIPARC) for older adults. Residents over the age of 65 years (N=307, mean age 84) were recruited from 11 retirement communities in San Diego. Study evaluation included collection of blood pressure measures and 6 day hip-worn accelerometry data. Change in blood pressure (dependent variable) and PA (intensity and total) from baseline to 6 months and 6 months to 12 months were examined. To account for within person and within group clustering, hierarchical longitudinal mixed effect models were used. Results: Increases in total PA counts was related to significant decreases in systolic blood pressure over the 12-month intervention period, after adjusting for minutes of time spent in MVPA (p<.005). Conclusions: Evidence is mixed on the intensity of PA needed for older adults to experience significant health benefits, including reducing blood pressure. The results of this study suggest that for older adults, the total accumulation of PA at any intensity, is more important than PA at moderate to vigorous intensities. These findings have important implications for the design of PA interventions and PA prescriptions for older adults. More research is needed in older adult populations to examine if MVPA is beneficial to older adults, or if the relationship varies by an individual’s cardiovascular health.