[Descriptive epidemiology of accelerometer-measured moderate to vigorous physical activity in Japanese older adults]

Most physical activity (PA) guidelines for health promotion recommend moderate to vigorous PA (MVPA) lasting at least 10 minutes (long-bout MVPA). However, recent studies have shown the beneficial effects of short-bout MVPA (intermittent and lasting <10 minutes). Therefore, we aimed to clarify the detailed patterns of MVPA of community-dwelling older adults using accelerometers.

This is a cross-sectional descriptive study. Community-dwelling older Japanese adults (total: 1,210; 70-80 years of age) randomly selected from residential registries of 3 municipalities (Bunkyo, Fuchu, and Oyama) were asked to wear an accelerometer (HJA-350 IT; Omron Healthcare, Japan). MVPA was classified by bout length (1-4, 5-9, 10-19, 20-29, and > 30 minutes). The mean frequency and duration of MVPA by each bout length and the proportion of long-bout MVPA were described.

Valid data were obtained from 450 participants (men: 56.7%; mean age: 74 years). The mean±standard deviation of the frequency and duration of MVPA bouts were 21.8±14.6 times/day and 2.1±0.9 min, respectively. The total duration of MVPA was 46.5±33.0 min/day. Long-bout MVPA accounted for 26.9%±23.5% of daily MVPA, whereas MVPA of 1-4 minutes accounted for 43.4%.

Older adults performed about 45 minutes of MVPA a day, but most of this was short-bout MVPA, which is overlooked by current WHO PA guidelines. In particular, short-bout MVPA was frequent among older women and those living in rural areas.