Background: Sedentary behaviour leads to increased blood pressure (BP), and regular physical activity reduces BP. However, the extent to which elevated BP associated with sedentary behaviour can be offset by regular physical activity is unknown, and was the aim of this study.

Methods: Study participants (n=637, aged 66.3±7years; 49% male) were from the Tasmanian Older Adult Cohort Study, which was a randomly selected community sample of older men and women aged 50–79 years. Average time spent per day in sedentary behaviour (e.g. sitting/lying) and physical activity (light, moderate and vigorous intensity) was determined by accelerometers (worn over 1 week). Brachial BP was measured by automated oscillometry.

Results: The average activity levels per day were: sedentary (584±94 min), light (227±72 min), moderate (32±25 min) and vigorous (1±4 min) intensity. Participants in the highest tertile of sedentary time had the highest pulse pressure (PP; p=.014) and highest prevalence of isolated systolic hypertension (p<.001). Sedentary time was significantly associated with PP (r=0.110; p=.005). This association remained significant on multiple regression analysis after adjustment for physical activity levels, sex, body mass index and presence of diabetes (β=.158; p=.005). Age was also associated with PP and this was both independent of, and partially mediated by, sedentary time.

Conclusions: The amount of time spent sedentary is independently associated with increased PP in older adults and could be one reason why PP increases with age. This suggests decreasing sedentary behaviour in older people could help to achieve better BP control, regardless of the level of physical activity.