<b>Association of Screen Time with Cardiopulmonary Endurance among Adolescents</b>

Background: Excessive screen exposure is increasingly common among adolescents and may contribute to sedentary behavior, reduced physical activity, and poorer health-related fitness. However, the direct association between screen time and functional cardiopulmonary capacity remains unclear, particularly in local school-going adolescent populations. Objective: This study aimed to determine the association between total, work-related, and recreational screen time and Six-Minute Walk Distance among adolescents aged 10–19 years. Methods: A cross-sectional analytical study was conducted among 194 adolescents in Lahore, Pakistan. Screen time was assessed using the Questionnaire for Screen Time of Adolescents, while functional cardiopulmonary capacity was assessed using the Six-Minute Walk Test. Pre-exercise heart rate, post-exercise heart rate, and heart rate recovery were also recorded. Data were analyzed using descriptive statistics, Pearson correlation, and multiple linear regression, with Six-Minute Walk Distance as the dependent variable. Results: The mean age was 14.54 ± 2.879 years, and male and female participants were equally represented. Mean total screen time was 6.60 ± 2.029 hours/day, while mean Six-Minute Walk Distance was 547.73 ± 80.123 m. Total screen time (r = 0.124, p = 0.085), work-related screen time (r = 0.010, p = 0.885), and recreational screen time (r = 0.133, p = 0.065) were not significantly correlated with Six-Minute Walk Distance. Pre-exercise heart rate (r = −0.975, p < 0.001) and post-exercise heart rate (r = −0.909, p < 0.001) showed strong inverse correlations with walking distance. The regression model including total screen time, age, gender, and BMI was not statistically significant, F(4,189) = 1.620, p = 0.171, and explained 3.3% of variance in Six-Minute Walk Distance. Conclusion: Screen time was not significantly associated with Six-Minute Walk Distance in this adolescent sample, whereas heart rate parameters showed stronger associations with functional walking capacity. Future studies should include objective physical activity monitoring, standardized heart rate assessment, and longitudinal designs