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 (rho = -0.64; P =.007), humidity (rho = -0.68; P =.004) and rain (rho = -0.67; P =.004) were inversely correlated to MVPA in the Summer. Rain was also inversely correlated to MVPA in the Spring (rho = -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.