A significant U-shaped association between physical activity level and posttraumatic stress disorder in U.S. military Veterans: Results from the 2019–2020 National Health and Resilience in Veterans Study

Abstract

ObjectiveThe present study sought to extend previous research by examining associations between physical activity levels, PTSD, and PTSD symptom clusters in a large, independent, nationally representative sample of U.S. military veterans. MethodsUsing data from the 2019–2020 National Health and Resilience in Veterans Study (NHRVS), we examined relations between a comprehensive self-report measure of physical activity that reflects public health guidelines and a self-report measure of DSM-5-defined PTSD and a 7-factor model of PTSD symptom dimensions. A total of 3,875 participants completed all study measures. Post-stratification weights were applied to all analyses (weighted n = 3,732). ResultsQuadratic logistic regression revealed a significant (p < .05) U-shaped association between physical activity levels (insufficient, moderate, and active) and a positive PTSD screen. A moderate activity level was associated with the lowest likelihood of PTSD (3.8% adjusted probability) while an active level was associated with the highest likelihood of PTSD (7.8% adjusted probability). Multinomial logistic regression suggested that more severe posttraumatic intrusive symptoms, particularly nightmares, and anhedonic symptoms were associated with a significantly decreased probability of a moderate activity level (ps ≤ .05, false discovery rate corrected). ConclusionsFindings suggest that a moderate physical activity level is associated with a lower likelihood of PTSD but that specific PTSD symptoms may be differentially associated with exercise behaviors. Candidate mechanisms and clinical implications of these findings are discussed.