Mobile internet use, physical exercise and depression levels: mediating mechanism and empirical evidence

Mental health has increasingly become a central component of national health agendas worldwide, aligning with the World Health Organization's commitment to comprehensive and equitable health for all. This study examines the effect of mobile internet use on residents' depressive symptoms and explores the behavioral mechanisms underlying this relationship.

Using nationally representative panel data from the China Family Panel Studies (CFPS) for 2020-2022, this study employs a two-way fixed-effects model to empirically examine the effect of mobile internet use on residents' depressive symptoms. Additional analyses are conducted to address potential endogeneity, explore the mediating role of physical exercise frequency, and examine heterogeneity across population subgroups.

The results show that mobile internet use significantly reduces depressive symptoms, and this finding remains robust after accounting for potential endogeneity. Further exploratory mediation analysis suggests that physical exercise frequency may serve as an important behavioral pathway through which mobile internet use alleviates depressive symptoms. Heterogeneity analyses further reveal that the depression-reducing effect of mobile internet use is more pronounced among vulnerable groups, including individuals with abnormal BMI, non-agricultural workers, workers in non-knowledge-intensive industries, and those without pension security.

Overall, these findings have important policy implications for promoting equitable digital access, designing targeted mental health interventions for vulnerable populations, and institutionalizing internet-enabled health promotion strategies.