Smartphone Addiction And Sleep Quality In The Physical Activity-anxiety Link: A Mediation-moderation Model

PURPOSE: Anxiety symptoms are common among university students in China, posing challenges to mental health. Physical activity may reduce anxiety, but the mechanisms are not fully understood. This study examines how smartphone addiction acts as a mediator and sleep quality as a moderator in the relationship between physical activity and anxiety, aiming to offer theoretical insights and practical strategies for mental health interventions. METHODS: A total of 719 students were recruited through stratified random sampling. Validated instruments included the International Physical Activity Questionnaire-Short Form (IPAQ-SF), Smartphone Addiction Scale-Short Version (SAS-SV), Pittsburgh Sleep Quality Index (PSQI), and Self-Rating Anxiety Scale (SAS). Data analysis involved standardization, descriptive statistics, Pearson correlation, normality testing, mediation and moderation analyses, and Bootstrap validation. RESULTS: (1) Physical activity was negatively correlated with smartphone addiction (r = -0.13, p < 0.01). (2) Smartphone addiction was positively correlated with poor sleep quality (r = 0.40, p < 0.01) and anxiety (r = 0.43, p < 0.01). (3) Poor sleep quality and anxiety were significantly correlated (r = 0.57, p < 0.01). (4) Mediation analysis indicated that smartphone addiction mediated the relationship between physical activity and anxiety, with physical activity indirectly reducing anxiety by decreasing smartphone addiction (β = -0.058). (5) Sleep quality significantly influenced the link between smartphone addiction and anxiety, especially in those with poorer sleep, where the impact of smartphone addiction on anxiety was stronger (β = 0.061, p = 0.036). CONCLUSIONS: This study elucidates that physical activity indirectly mitigate anxiety by reducing smartphone addiction. Furthermore, sleep quality emerges as a significant moderating factor, affecting the relationship between smartphone addiction and anxiety levels. Based on these findings, it is recommended that higher education institutions implement health promotion programs to increase physical activity and improve sleep quality, thereby reducing smartphone dependence and alleviating anxiety symptoms.