The increasing use of wearable devices for measuring long-term activity data allows for detailed analyses of real-life behavioral patterns and for the identification of new parameters such as activity event regularity. Thus far, the medical relevance of this new regularity parameter is unknown. The objective of the research work for this paper is to investigate associations between activity regularity and resting systolic blood pressure, as an exemplary well-established cardiovascular risk factor. Using accelerometer and blood pressure data of N=5695 subjects from the NHANES 2005-6 cohort study, three characteristic physical activity parameters (regularity, duration and intensity) were computed and compared for the upper and lower quartiles of subjects with regard to their blood pressure values. Results show statistically significant differences in the parameters regularity (p<0.001) and duration (p=0.008) of physical activity events, but not in intensity (p=0.889). Results confirm that subjects with low resting systolic blood pressure not only are active for longer periods of time, but also are more regularly active. It also shows that low-intensity, short-lived physical activity (< 10 min.) is associated with health-related outcome parameters. More research is necessary to make full use of detailed activity behavior data, and in particular to uncover relations between physical activity patterns and health outcome.