Timing Matters: A Longitudinal Study Examining the Effects of Physical Activity Intensity and Timing on Adolescents’ Mental Health Outcomes

Physical activity is universally acknowledged for its benefits to mental health; however, the specific intensities and timings that best benefit adolescents’ mental health, crucial due to their significant influence on daily schedules, have not been thoroughly investigated. This study addresses the substantive research gap by exploring the varied effects of physical activity intensity (light versus moderate to vigorous) and timing (weekdays versus weekends and holidays) on adolescent mental health. Utilizing a large-scale longitudinal dataset (NT1 = 84,054; NT2 = 44,623) from 158 schools, this research describes the current state of adolescent physical activity and investigates the effects of physical activity on mental health outcomes, including positive (i.e., life satisfaction, positive mental health) and negative indicators (depression, anxiety), over a 6-month period. Participants were adolescents aged 9–19 years (mean age = 12.73 ± 2.43 years, 48.9