Physical activity among Norwegian preschoolers varies by sex, age, and season

Background
Knowledge of physical activity (PA) in preschool populations is important for public health promotion. We investigated levels of PA in a large sample of Norwegian preschoolers and explored variations and development in PA by sex, age, and season.

Methods
Physical activity levels of 1154 children (mean age 4.7 years, 52% boys) were measured by accelerometry (ActiGraph GT3X+) for 14 consecutive days between autumn 2015 and summer 2016. Additionally, 330 children provided up to 3 repeated measurements of PA across seasons. A linear mixed model was applied to analyze associations and interactions of total PA (cpm), light PA (LPA), moderate PA (MPA), vigorous PA (VPA), moderate‐to‐vigorous PA (MVPA), sedentary time (SED), sex, age, and season.

Results
Boys and girls spent mean (standard deviation) 72 (21) and 59 (18) min/d in MVPA and had a total PA of 790 (202) and 714 (192) cpm/d, respectively. Boys had higher PA levels than girls, PA increased with age, and PA was higher during spring/summer than autumn/winter (P < 0.001). Boys had a greater increase in PA by age than girls (P < 0.05), mainly due to increased MVPA during spring/summer (p for sex × age × season=0.009).

Conclusions
Boys were consistently more active and less sedentary than girls, and PA increased with age for both sexes. Boys exhibited a greater increase than girls in PA by age, and PA differed across seasons, with higher levels of MVPA during spring/summer. Differences in MVPA between boys and girls, among age groups, and among seasons seem to be interrelated, indicating that many factors influence preschoolers’ PA.