Objectively Measured Age-Related Changes in the Intensity Distribution of Daily Physical Activity in Adults

Abstract

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-ax-ial 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.