Intensity of habitual physical activity and maintenance of normal blood pressure - findings from the SUN longitudinal cohort study

(2)BackgroundPhysical activity (PA) is a modifiable protective factor against hypertension, but the optimum intensity of PA for prevention of hypertension remains unknown. It has been suggested that total energy expenditure is the crucial factor while intensity is non-differential provided it is moderate or above. Yet it is possible that higher intensity PA may produce a distinct effect. MethodsWe used data from the Seguimiento Universidad de Navarra (SUN) cohort - a large prospective longitudinal cohort study in Spain - to investigate how intensity of habitual PA may affect hypertension incidence. Average intensity of PA was calculated incorporating incidental walking and stairclimbing in addition to leisure-time PA (LTPA). Hazard ratios (HRs) for incident hypertension and their 95% confidence intervals (CI) were estimated using Cox regression analyses, and modelling adjusted for EE and body mass index (BMI) as well as other important covariables. Comparative models investigated how time spent in PA and EE in PA relate to hypertension incidence. Results17,146 normotensive participants (63.6% female, mean age 36.7 years, mean BMI 23.2kg/m2) were followed for 204,677 person-years. 2,495 cases of incident hypertension emerged. After adjustment for covariables, including EE, intensity of PA was monotonically associated with decreased risk for incident hypertension (aHR for Q5 vs Q1: 0.81, 95% CI 0.71-0.93). In comparison, increasing time in PA was associated with increasing risk for incident hypertension following adjustment for EE (aHR for Q5 vs Q1: 1.60, 95% CI 1.10- 2.32). ConclusionIntensity of habitual PA is independently and inversely associated with incidence of hypertension.