RESUMEN
This study investigated the association between physical activity (PA) and midlife income. The population-based data comprised employed members of the Northern Finland Birth Cohort 1966 (N = 2797). Using binned scatterplots and polynomial regressions, we evaluated the association between accelerometer-measured moderate PA (MPA), vigorous PA (VPA), and moderate-to-vigorous PA (MVPA) at 46 years old and register-based income at 50 years old. The models were adjusted for sex, marital status, number of children, education, adolescent PA, occupational physical strenuousness, and time preference. We found MPA (p < 0.001), VPA (p < 0.05), and MVPA (p < 0.001) to associate curvilinearly with income. In subgroup analyses, a curvilinear association was found between MPA (p < 0.01) and MVPA (p < 0.01) among those with physically strenuous work, VPA among all females (p < 0.01) and females with physically light work (p < 0.01), and MPA and MVPA among all males and males with physically strenuous work (p < 0.05; p < 0.01; p < 0.05; p < 0.05, respectively) and income. The highest income benefits occurred at PA volumes higher than current PA guidelines. Linear associations between PA and income were found among females for MPA (p < 0.05) and MVPA (p < 0.05), among those with physically light work for MPA (p < 0.05), VPA (p < 0.05), and MVPA (p < 0.05), and among females with physically strenuous work for VPA (p < 0.05). We conclude that PA up to the current recommended level is associated with income, but MPA exceeding 505.4 min/week, VPA exceeding 216.4 min/week, and MVPA exceeding 555.0 min/week might have a negative association with income.