[Occupational factors and physical activity among public school teachers: a prospective cohort study].

The association between self-reported changes in working conditions and the incidence of recommended levels of leisure-time physical activity (LTPA) among middle and high school teachers of the public school network was analyzed. It is a prospective cohort in which 298 teachers from the public middle and high school network in Londrina, State of Paraná, were monitored for 24 months. The incidence of recommended LTPA levels (≥150 minutes/week) was the study outcome. The analysis included adjusted Poisson regression models, using those who had the worst working conditions in the baseline, and remained unchanged in the follow-up, as a reference group. The incidence of recommended levels of LTPA was 23.2%, being higher among those who maintained a good balance between their personal and professional lives (RR=3.50; 95%CI=1.26-9.72), frequently became exhausted at work (RR=2.47; 95%CI=1.10-5.56), infrequently became exhausted at work (RR=2.42; 95%CI=1.09-5.36), rarely became exhausted at work (RR=2.78; 95%CI=1.30-5.95), rarely began to work too hard (RR=2.69; 95%CI=1.24-5.87) and those who rarely needed to work too much (RR=3.25; 95%CI=1.46-7.26). These results indicate the importance of improving working conditions in the promotion of AFTL.