Temporal Associations Between Specific Depressive Symptoms and Physical Inactivity in Middle Aged and Older Adults.

Being physically inactive can worsen mental health. Physical inactivity and depression are associated, but the temporal precedence and underlying mechanism are unclear; symptoms affecting future physical activity may not be the same symptoms as those associated with and affected by it. We used large European cohort (Survey of Health, Ageing, and Retirement in Europe, SHARE, N = 124, 526) to study temporal associations between physical inactivity and individual depressive symptoms. Multivariate regression with robust standard errors were used to analyze how physical inactivity is associated with later depression and how depressive symptoms predict later physical inactivity. After adjusting the models for demographics, other health behaviors, BMI, and chronic diseases, physical inactivity was prospectively associated with 10 of the 12 depressive symptoms and 7 of the 12 baseline depressive symptoms were prospectively associated with physical inactivity. These findings were robust for adjusting for antidepressant medication. Age-stratified analyses suggested that the associations between physical inactivity and depressive symptoms were independent of age. Omitting the most influential symptom, lack of enjoyment, from the sum score attenuated the association by 13% in the longitudinal and by 26% in the cross-sectional analyses. These findings suggest that physical inactivity and depression are bidirectionally associated even at symptom-level.

Physical activity and specific symptoms of depression: A pooled analysis of six cohort studies.

BACKGROUND: The association between physical activity (PA) and depression is well-established, but the details that explain this association remain elusive. We examined whether PA is differentially associated with specific symptoms of depression (e.g., cognitive vs somatic symptoms), and whether these associations follow a dose-response pattern with respect to intensity or frequency of PA. METHODS: Cross-sectional analyses were based on 6 samples of the continuous U.S. National Health and Nutrition Examination Surveys (NHANES) carried out between 2007 and 2018 (n = 28,520). Depressive symptoms were assessed with Patient Health Questionnaire 9 (PHQ-9). Information about PA (vigorous, moderate, and daily commuting by foot or bike) and covariates was self-reported. RESULTS: After adjusting for education, health behaviors, body-mass index, physical functioning, and all the other depressive symptoms, lower PA was specifically associated with four depressive symptoms: loss of interest/pleasure, feeling down/hopeless, fatigue, and changes in appetite (odds ratios from 0.94 to 0.59). A monotonic dose-response pattern on PA amount was observed only for interest/pleasure and fatigue, and these associations were independent of PA intensity. LIMITATIONS: Cross-sectional data did not allow us to assess temporal ordering. Both depressive symptoms and PA were self-reported, which may induce bias. CONCLUSION: Low PA may be linked to depressive symptoms particularly through the symptoms of anhedonia and fatigue. Given that their association with PA amount follows a dose-response pattern and is independent of PA intensity, we hypothesize that behavioral activation and exposure to rewarding experiences might help to explain why PA alleviates depression.