One-year Stability of Objectively Measured Physical Activity in Young Brazilian Adults.

BACKGROUND: To evaluate the 1-year stability of objectively measured physical activity among young adults living in South Brazil, as well as assessing the influences of temperature, humidity and precipitation on physical activity.

METHODS: A longitudinal study was conducted over 12 consecutive months (October 2012 to September 2013). Sixteen participants (8 men) used GT3X+ accelerometers 1 week per month for the entire year. Climate variables were obtained from an official climate information provider.

RESULTS: Physical activity was remarkably stable over the year-the proportion of the day spent in moderate-to-vigorous intensity physical activity (MVPA) was around 5% in every month. Average temperature (ρ = -0.64; P = .007), humidity (ρ = -0.68; P = .004) and rain (ρ = -0.67; P = .004) were inversely correlated to MVPA in the Summer. Rain was also inversely correlated to MVPA in the Spring (ρ = -0.54; P = .03).

CONCLUSIONS: Objectively measured physical activity was stable over a 1-year period. Climate variables consistently influenced physical activity practice in the Summer, but not in the other seasons.