The momentary relationship between physical activity behaviour and mental well-being of vocational education and training students

Vocational education and training (VET)-students often face student mental well-being (SMW) challenges. Physical activity behaviour (PAB) is positively associated with SWM, yet SMW can vary during the day. Therefore, this study aims to explore the momentary relationship between PAB ((i.e., moderate to vigorous physical activity (MVPA), light physical activity (LPA), sedentary behaviour (SB)) and SMW (i.e., affect, self-esteem). For 9 consecutive days, VET-students reported their SMW via experience sampling methods-prompts while their PAB was measured with thigh worn ActivPALs™. PAB data was summed in minutes spent in each PAB 30 and 60 min before each prompt. Data of 68 students (68% female, mean-age = 18.9 ± 4) was analysed with multilevel regression analyses. Consistently positive associations between LPA and positive affect (30min: β = 0.03, p = <0.001, 60min: β = 0.03, p = <0.001), and self-esteem (30min: β = 0.01, p = .047 60 min: β = 0.01, p = <0.001) were found. For SB negative associations for positive affect (30 min: β = −0.04, p = <0.001, 60 min: β = −0.03, p = <0.001), and self-esteem (30 min: β = −0.02, p = < 0.001, 60 min: β = −0.01, p = < 0.001) were found. No associations were found between any PAB and negative affect, and for MVPA and SMW. The significant positive associations between LPA and SMW and the negative associations between SB and SMW suggest that increasing LPA and decreasing SB and can improve SMW in VET students. • Objectively measured light physical activity is consistently positively associated with momentary student mental wellbeing. • Objectively measured sedentary behaviour is consistently negatively associated with momentary student mental wellbeing. • Objectively measured moderate-to-vigorous physical activity is not associated with momentary student mental wellbeing.