In our previous study, we demonstrated that an increase in the amount of daily physical activity might produce beneficial effects on aging-induced reduction of systemic arterial compliance. Regular physical activity, especially vigorous activity levels, inhibits age-related decrease in sytemic or central arterial compliance. However, the effect of mild to moderate intensity of physical activity has not been fully elucidated. The purpose of the present study was to investigate which intensity level of physical activity would be effective to improve systemic arterial compliance. We examined the relationship between systemic arterial compliance and intensity levels of daily physical activity (activity time corresponding to <3 METs [low], <3 METs and <6 METs [mild-moderate], and >6 METs [high]) in 413 middle-aged and elderly subjects (46∼85 y). Multiple regression analysis detected age and time of mild-moderate intensity of daily physical activity as significant independent determinants of systemic arterial compliance. The time of mild-moderate intensity of daily physical activity was significantly related to age and amount of daily physical activity. After age and amount of daily physical activity were taken into account (analysis of covariance), systemic arterial compliance was significantly higher in people who had ≥30min/day of the mild-moderate daily physical activity compared with those who had <30min/day of mild-moderate daily physical activity. These findings suggest that increases not only in the amount of total daily physical activity but also in time of daily physical activity of mild-moderate intensity could improve age-induced reduction of systemic arterial compliance.