Prevalence and correlates of self-reported and accelerometer-determined sedentary behavior and physical activity of German university students: cross-sectional results of the SmartMoving study.

BACKGROUND

Sedentary behavior (SB) and the absence of physical activity (PA) have become increasingly prevalent in modern societies due to changes in physical and social-environmental conditions, particularly in university students. This cross-sectional study aimed to describe and identify the prevalence and correlates of self-reported and accelerometer-determined SB and PA of German university students.

METHODS

A convenience sample of 532 students participated in a questionnaire survey during the lecture period in the summer term 2018. Self-reported total PA, university-, travel-, and leisure-time-related PA were calculated, in addition to self-reported sitting time (ST) within the university. A sub-sample of forty-six participants also received body composition measurements and then wore an ActiGraph wGT3X-BT for seven consecutive days to objectively determine SB, PA, and sleep duration. Differences in descriptive characteristics between samples were analyzed using independent t-test for normally distributed variables or the nonparametric or Mann-Whitney U-Test for not normally distributed variables. Forward stepwise logistic regression analyses were used to analyze correlates associated with self-reported SB and PA in the university context. Stepwise, multiple linear regression analysis was used to determine the associations of anthropometric, sociodemographic, study-related, self-reported SB and PA variables with objectively-determined SB controlling for potential confounders.

RESULTS

Self-reported ST within the university was 2020.5 min/week (95% CI: 1915.8-2125.1), while females reported a 4 h per day higher ST compared with male students (p = 0.023). Self-reported PA exclusively at the university was 211.9 min/week (195.3-228.6) with additional time in active travel (AT) of 266.1 min/week (236.8-295.4). Students with higher amounts of sitting (e.g. in the library or in lectures; p < 0.001) and students who had lower time in AT (p = 0.023) were more likely to be sedentary in the university context. Furthermore, students with a higher monthly net household income (p = 0.043), higher values in university-related PA (e.g. walking between lectures or stair climbing; p < 0.001) and students who were also engaged in higher times of AT (p = 0.004) were more physically active at the university compared with students in the reference group. Correlates associated with accelerometer-determined SB included light-intensity PA (LIPA; p < 0.001), moderate-to-vigorous PA (MVPA; p < 0.001), sleep duration (p < 0.001), monthly net household income (p = 0.006) and total cycling time at the university (p = 0.032).

CONCLUSION

Our sample of university students were highly sedentary, but also very active and met current PA recommendations. Daily LIPA, MVPA and also sleep duration were negatively associated with accelerometer-determined SB. Beyond that, daily AT might be a supporting correlate to reduce SB in university students and should be considered as a key variable in future longitudinal interventional studies on activity-friendly and health promoting university environments.