Isotemporal substitution of sedentary behavior with physical activity and its influence on depressive symptoms among adults with overweight/obesity in the United States: A cross-sectional study

Objective: This cross-sectional study examined the influence of sedentary behavior (SB) time substitution with physical activity (PA) on depressive symptoms among adults with overweight/ obesity. SB time was replaced with equal amount of walking/bicycling or leisure-time moderateto-vigorous PA (MVPA). Methods: Data of the 18344 adults, who were overweight and obesity was obtained from the National Health and Nutrition Examination Survey 2006-2018. PA of participants was measured by the Global Physical Activity Questionnaire. Depressive symptoms, including overall, somatic, and cognitive depressive symptoms were assessed by the Patient Health Questionnaire-9 (PHQ-9). Isotemporal substitution model based on weighted multiple linear regression was used to assess the association of SB time substitution with PA on depressive symptoms. Results: Independent model analysis showed that 30 min/day SB time was significantly associated with higher PHQ-9 depressive symptoms, while engage in walking/bicycling or leisure-time MVPA for 30 min/day was associated with lower depressive symptoms. Isotemporal substitution analyses revealed that replacing 30 min/day SB time with equal amount of walking/bicycling or leisure-time MVPA was associated with significant lower PHQ-9 total scores (walking/bicycling: (3 = -0.088, 95%CI = -0.129, -0.047, P G 0.01; MVPA: (3 = -0.160, 95%CI = -0.185, -0.134, P G 0.01). Moreover, cognitive depressive symptoms (walking/bicycling: (3 = -0.035, 95%CI = -0.058, -0.013, P G 0.01; MVPA: (3 = -0.074, 95%CI = -0.088, -0.060, P G 0.01), and somatic depressive symptoms (walking/bicycling: (3 = -0.053, 95%CI = -0.075, -0.030, P G 0.01; MVPA: (3 = -0.085, 95%CI = -0.100, -0.071, P G 0.01) were also significantly lower after replacing SB time with either walking/bicycling or MVPA. However, replacing 30 min/day PA with SB time represented with higher depressive symptoms. Conclusions: Replacing SB time with walking/bicycling or MVPA is beneficial in lowering the depressive symptoms among overweight/obese adults. Owing to the benefits of PA on depression, strategies promoting PA participation, are necessary for better social/mental well-being and healthy society.