Associations of insomnia symptoms and physical activity with life satisfaction and psychological well-being among secondary school students in Spain: a cross-sectional study

Introduction Insomnia symptoms and physical inactivity are common during adolescence and may be associated with poorer well-being. However, their independent associations with different well-being indicators remain insufficiently examined in Spanish secondary school students. Objective To examine the independent associations of insomnia symptoms and physical activity with life satisfaction and psychological well-being among adolescents, after adjusting for sociodemographic factors. Methods A cross-sectional study was conducted among 462 secondary school students from six schools in Zaragoza, Spain. Participants completed self-report measures of insomnia symptoms, physical activity, life satisfaction, psychological well-being, and subjective social status. Hierarchical multiple linear regression models with bootstrap confidence intervals were used to examine the contribution of insomnia symptoms and physical activity beyond age, gender, geographical area, and subjective social status. Results The mean Insomnia Severity Index score was 9.08 (SD = 4.58), and 59.1% of students presented subthreshold, moderate clinical, or severe clinical insomnia symptoms. The mean PAQ-A score was 2.67 (SD = 0.77), with 57.1% of students classified as physically inactive. Insomnia symptoms were negatively associated with both life satisfaction and psychological well-being, whereas physical activity was positively associated with both outcomes. The addition of insomnia symptoms and physical activity increased the explained variance in life satisfaction and psychological well-being beyond sociodemographic covariates. Insomnia symptoms showed larger standardised associations than physical activity in both models. Discussion Insomnia symptoms and physical activity were independently associated with well-being indicators among Spanish adolescents. School-based strategies addressing both sleep health and physical activity may contribute to adolescent well-being, although longitudinal and intervention studies are needed to clarify the directionality of these relationships.