Duration of Keeping an Exercise Habit and Mental Illness and Life Attitude among University Students

Physical exercise has beneficial effects on human health, and several studies have examined the association between exercise and mental health. However, most of these studies focused on exercise intensity, duration, or frequency. Evidence for the association between the duration of maintaining an exercise habit and mental illness is lacking, especially in young adulthood-a crucial period that bridges adolescence and adulthood. This study investigated the association between the duration of keeping an exercise habit and mental illness and life attitude among Chinese university students. A total of 11,392 university students participated in this study (6866 men and 4526 women). The duration of keeping an exercise habit was evaluated using a questionnaire with relevant questions. Exercise habit was defined as exercising for longer than 30 min per session and more than twice a week. Mental illness consisted of two elements: depressive symptoms-assessed using the Zung Self-rating Depression Scale, and anxiety symptoms-assessed using the seven-item Generalized Anxiety Disorder scale. Life attitude was assessed using a questionnaire with relevant questions. Multivariate logistic regression analysis examined the adjusted association between the duration of keeping an exercise habit and mental illness and life attitude. In the final adjusted model, compared to the no exercise category, the odds ratios and 95% confidence intervals (CIs) of depressive symptoms were 0.80 (0.70, 0.91) for those with an exercise habit of 1-4 months, and 0.72 (0.63, 0.83) for those with one of >4 months (p for trend <0.001). Additionally, when compared to participants with no exercise habit, the adjusted odds ratios (95% CIs) for anxiety symptoms were 1.01 (0.90, 1.14) for those with a habit of 1-4 months and 0.78 (0.69, 0.88) for those with one of >4 months (p for trend =0.001). A longer duration of keeping an exercise habit was also significantly associated with positive life attitudes. Our results showed that a long duration of keeping an exercise habit was significantly associated with a lower prevalence of mental illness among university students. Further, maintaining a more prolonged exercise habit may benefit individuals' mental health in young adulthood.