This study aims to analyze the associations of 24-hour physical activity (PA) behaviors, including moderate-to-vigorous intensity physical activity (MVPA), light-intensity physical activity (LPA), sedentary behavior (SB), and sleep, and the effects of their redistribution on body composition markers in college students. A cross-sectional survey was conducted among 108 college students (51 males and 57 female) in Hangzhou. ActiGraph GT3X+ accelerometers were used to objectively measure 24 h PA behaviors. The height, weight, waist circumference (WC) and hip circumference of the participants were measured by standard measuring instruments, and body mass index (BMI) and waist-hip ratio (WHR) were calculated. Body fat percentage (BFP), visceral fat area (VFA), fat mass and fat-free mass were measured using the InBody 720. Compositional linear regression was used to analyze the relationship between 24 h physical activity behavior and these parameters. 1) Compositional regression analysis showed that MVPA was negatively correlated with BMI, BFP, WHR, WC, fat mass and VFA after adjusting for age, sex, monthly expenditure, smoke status, and alcohol consumption (p < 0.05). LPA was also negatively correlated with WC and fat mass (p < 0.05), while SB was positively correlated with BFP, WC and fat mass (p < 0.05). 2) Replacing sleep or SB with MVPA for 15 min, BMI, BFP, WHR, WC, fat mass, and VFA were significantly decreased (p < 0.05). When LPA was replaced with MVPA for 15 min, BFP, WHR, WC and fat mass also significantly decreased (p < 0.05). While replacing SB with LPA for 15 min, it results in reductions in BMI, BFP, WHR, WC and fat mass (p < 0.05). However, after replacing MVPA with sleep, SB or LPA for 15 min, BMI, BFP, WHR, WC, fat mass and VFA significantly increased (p < 0.05), and LPA was replaced with SB for 15 min, BMI, BFP, WC and fat mass significantly increased (p < 0.05). 3) Dose-effect analysis showed that the substitution of MVPA and other activitys had asymmetric effects on BMI. MVPA had the best effect on BMI reduction when it replaced SB; With the prolongation of MVPA substitution for other activities, the degree of BMI reduction was gradually decrease. However, with the gradual increase of other activities replacing MVPA, BMI showed a rapid increase. Our findings indicate that increased MVPA time is associated with lower levels of BMI, BFP, WHR, WC, fat mass and VFA, and increased SB associated with increased BFP, WC and fat mass. Thus, replacing SB with MVPA or LPA may be effective strategies for improving body composition in college students and decrease the risk of obesity for college students.
Chen et al. (Thu,) studied this question.