Background: The purpose of the present investigation was to examine the relationship between age and the intensity of the daily physical activity in men and women, aged 18 to 69 years.
Methods: A total 507 volunteers continuously wore a pedometer with a uni-axial accelerometer (Lifecorder, Kenz, Japan) for 7 days, to determine the number of steps (steps/ day) as well as the time spent in physical activity (minutes/day) at light (below 3 METs), moderate (3 to 6 METs), and vigorous (above 6 METs) intensities, respectively. All procedures carried out in the present investigation were conducted from 1999 to 2000 in Japan.
Results: The time spent in moderate to vigorous intensity physical activity significantly decreased with aging (P < 0.01). In contrast, the middle- to older-aged individuals spent a longer time in light intensity physical activity in comparison with the younger individuals (P < 0.05). Furthermore, these age-associated differences of physical activity were also significant, even though the number of steps did not differ significantly.
Conclusions: These results indicate that the intensity of daily physical activity decreases with increasing age regardless of the amount of daily physical activity.