[영문]The interactions of sex, age, season, and habitual physical activity were examined in 41 male and 54 female Japanese age 65?83 yr, using a pedometer/accelerometer that determined step counts and amounts of physical activity (qqqlt;3 and qqqgt;3 metabolic equivalents [METs]) throughout each 24-hr period for an entire year. All 3 measures were greater in men than in women. In women, age was negatively correlated with step count and activity qqqlt;3 METs, but in men, it was correlated with step count and activity qqqgt;3 METs. Irrespective of sex or age, all 3 activity variables were low in the winter, peaking in spring or autumn. In the summer, step counts matched the annual average, but durations of activity qqqlt;3 and qqqgt;3 METs were, respectively, longer and shorter than in other seasons. These findings have practical implications for those promoting physical activity for older adults.