Bidirectional association between mental health and physical activity in older adults: Whitehall II prospective cohort study

- We explored associations between mental health and physical activity in older adults over 10 years.
- Mental health and physical activity were correlated at baseline and moved together over time.
- Greater physical activity was associated with better mental health in early old age, and vice versa.
- Our findings suggest persistent positive longitudinal and bidirectional associations.
- Neither variable had a 'causal' impact on the other.

ObjectiveTo investigate longitudinal and bidirectional associations between mental health and physical activity from midlife into old age.MethodsAnalysis was based on data from 6909 participants (aged 45 to 69 in 1997/99) from the Whitehall II cohort in the UK. Latent growth curve analysis examined possible bidirectional associations between the SF-36 Mental Component Summary and weekly physical activity measured at three time-points over ten years.ResultsMental health and physical activity were associated at baseline (β = 0.17, 95% CI 0.13, 0.21) and associations persisted into old age. In the latent growth curve model, both mental health and physical activity increased and their rates of change 'moved together' over time (β = 0.24, 95% CI 0.11, 0.37). Relatively high baseline levels of either variable were associated with slightly slower increases in the other outcome (β = − 0.02, 95% CI − 0.03, − 0.01; β = − 0.07, 95% CI − 0.11, − 0.13), which are thought to reflect regression to the mean. However, those who started high on either variable remained the most advantaged at end of follow-up.ConclusionsFrom midlife to old age, greater physical activity is associated with better mental health and vice versa. These findings suggest persistent longitudinal and bidirectional associations between physical activity and mental health.