Association between movement behaviors and depression among vocational school students with different sleep duration - a study based on the isotemporal substitution model

The isotemporal substitution model can be used to explore the impact of the isotemporal substitution of different behaviors on human health. The association between sleep duration and mental health may be non-linear, but the relationship between the isotemporal substitution of movement behaviors and mental health in different sleep duration groups has not been explored. A questionnaire survey was conducted among Grade 1-3 students in 14 vocational schools in China, and 8149 valid questionnaires were obtained, of which 58.80% were in sleep-insufficient group, and 32.56% were detected with depression symptoms. The isotemporal substitution model was used for analysis. In the sleep-insufficient group, substituting 10 minutes/day of vigorous physical activity (β=-0.318, 95%I = -0.498~-0.138), walking (β=-0.254, 95%I = -0.381~-0.126) and sedentary behavior (β=-0.234, 95%I = -0.337~-0.130) with isotemporal moderate physical activity, or substituting vigorous physical activity (β=-0.465, 95%I = -0.577~-0.353), moderate physical activity (β=-0.147, 95%I = -0.263~-0.031), walking (β=-0.400,95%I = -0.476~-0.324) and sedentary behavior (β=-0.380,95%I = -0.434~-0.327) with isotemporal sleep, were negatively associated with depression; and substituting moderate physical activity (β = 0.318, 95%CI = 0.138 ~ 0.498) and sleep (β = 0.465, 95%CI = 0.353 ~ 0.577) with isotemporal vigorous physical activity was positively associated with depression. In the sleep-sufficient group, replacing sedentary behavior (β=-0.129, 95%I = -0.244~-0.013) with equivalent moderate physical activity was negatively associated with depression; replacing moderate physical activity (β = 0.219, 95%CI = 0.101 ~ 0.338), walking (β = 0.112, 95%CI = 0.040 ~ 0.185) and sedentary behavior (β = 0.091, 95%CI = 0.058 ~ 0.124) with equivalent sleep was positively associated with depression. For the sleep-insufficient group, substituting vigorous physical activity, walking, and sedentary behavior with isotemporal moderate physical activity and sleep had greater negative association with depression than the sleep-sufficient group. In conclusion, for the sleep-insufficient group, the substitution that was largest negatively associated with depression was sleep for other behaviors, and for sleep-sufficient group it was moderate physical activity for other behaviors. In future interventions, the sleep-insufficient group may achieve greater effects than the sleep-sufficient group if they use moderate physical activity and sleep instead of other behaviors.