Do the American guideline-based leisure time physical activity levels for civilians benefit the mental health of military personnel?

Backgrounds: This study aimed to clarify the association of American guideline-based leisure time physical activity (PA) level with mental health in 4,080 military personnel in Taiwan. Methods: The moderate intensity PA level was assessed according to the total running time per week (wk) reported in a self-administered questionnaire over the previous 6 months and was categorized into PA level <150, 150-299, and ≥300 min/wk. Mental stress was assessed by the Brief Symptom Rating Scale (BSRS)-5 for which ≥15 points were classified as great mental stress. Suicide ideation (SI) was graded as 1 for mild, 2 for moderate, and 3 or 4 for severe. Multivariable logistic regression analysis was employed to determine the association between PA and mental health while adjusting for demographics, smoking, alcohol intake, betel nut chewing, and obesity. Results: As compared to participants with a PA level of <150 min/wk., those with PA levels 150-299 min/wk. and ≥ 300 min/wk. had a lower possibility of SI ≥1 [odds ratios (ORs) and 95% confidence intervals (CIs): 0.58 (0.40-0.83) and 0.23 (0.14-0.36), respectively] and SI ≥1 and/or BSRS-5 ≥ 15 [ORs: 0.55 (0.39-0.79) and 0.21 (0.13-0.34), respectively]. The possibilities were more significantly lower for SI ≥2 [ORs: 0.37 (0.20-0.68) and 0.10 (0.04-0.26), respectively] and SI ≥2 and/or BSRS-5 ≥ 15 [ORs: 0.35 (0.20-0.62) and 0.10 (0.04-0.25), respectively]. Conclusion: Our findings indicate that participating in moderate-intensity leisure time PA level for ≥150 min/wk. may have a positive effect on mental health among military personnel. The impact appears to be even more significant when engaging in a higher PA level of ≥300 min/wk.