Associations among environmental supports, physical activity, and blood pressure in African-American adults in the PATH trial

High blood pressure disproportionately affects African-American adults and is a leading cause of stroke and heart attack. Engaging in recommended levels of physical activity reduces blood pressure, and social and physical environmental supports for physical activity may increase engagement in physical activity. Based on social cognitive theory within a bioecological framework, the present study tested hypotheses that perceived peer social support for physical activity and neighborhood walkability would be positively associated with physical activity, and that physical activity would mediate their relation with blood pressure. Baseline data were collected with 434 African-American adults in underserved communities (low income, high crime) participating in the Positive Action for Today's Health (PATH) trial. Perceived peer social support for physical activity and neighborhood walkability were measured with validated surveys. Physical activity was assessed with 7-day accelerometry (moderate-to-vigorous physical activity, min/day) and with a 4-week recall of walking. Three blood pressure assessments were taken by trained staff using standard protocols, with values from the second and third assessments averaged. The sample was predominantly female (63%), overweight (mean body mass index = 30.9, SD = 8.4), and had slightly elevated blood pressures with a mean systolic blood pressure of 132.4 (SD = 17.9) and a mean diastolic blood pressure of 81.4 (SD = 11.0). Results demonstrated that peer social support for physical activity (B = 2.43, p = .02) and neighborhood walkability (B = 2.40, p = .046) were significantly related to average daily moderate-to-vigorous physical activity. Neighborhood walkability was also significantly associated with self-reported average daily walking (B = 8.86, p = .02). Physical activity did not mediate their relation with blood pressure and no significant direct effects of these variables on blood pressure were found. The positive influence of social and physical environmental supports on physical activity in underserved African-American communities may guide intervention efforts and contribute to our understanding of physical activity and related health outcomes.