LAUSR

BACKGROUND Moderate to vigorous physical activity (MVPA) can help to prevent depression, but identification of the most important psycho-biological pathways involved is unclear. The improvement of cardio-respiratory fitness (CRF) in response to MVPA can vary markedly, we therefore examined the association between CRF and the incidence of depressive symptoms. METHODS We used data from The Maastricht Study, a large population-based prospective-cohort study. CRF was estimated at baseline from a graded submaximal exercise protocol and MVPA was measured with accelerometry. Depressive symptoms were assessed using the validated Dutch version of the 9-item Patient Health Questionnaire, both at baseline and during annual follow-up over five years. Cox proportional hazards models were used. RESULTS A total of 1,730 individuals without depressive symptoms at baseline were included in the analysis. During the 5-year follow-up, n = 166 (9.6%) of individuals developed depressive symptoms. Compared to individuals with a low CRF, those with a moderate-to-high CRF had a significantly lower risk of developing depressive symptoms, independent of MVPA (medium CRF: HR = 0.49 (95%CI = 0.33-0.72); high CRF: HR = 0.48 (95% CI = 0.30-0.75). These associations were adjusted for age, sex, level of education, diabetes status, smoking status, alcohol use, energy intake, waist circumferences and antidepressant medications. LIMITATIONS PHQ-9 is a validated screening instrument, but it is not a diagnostic tool of depression. CONCLUSIONS Higher CRF was strongly associated with a lower risk of incident depressive symptoms over 5-year follow-up, independent of the level of MVPA at baseline, suggesting that interventions aimed at improving CRF could reduce the risk of depression.