Title: Exploring Resistance Training as a Potential Standalone Treatment for Anxious Adults Who Screen Positive for Posttraumatic Stress Disorder
Description: Introduction: Posttraumatic stress disorder (PTSD) is a disabling psychological disorder that affects about 7% of adults in the United States. PTSD and its symptoms have consistently been shown to have an inverse relationship with exercise participation. The strongest reported associations have been between high intensity exercise, and the hyperarousal and avoidance symptom clusters. Importantly, resistance training (i.e., weight lifting) is thought to have beneficial effects for several conditions that commonly co-occur with PTSD, such as anxiety, depression, and poor sleep quality. However, no studies have examined the effects of high intensity resistance training on PTSD symptoms. Purpose: This study sought to examine the effects of a 3-week high intensity resistance training program on the PTSD hyperarousal and avoidance symptom clusters, sleep quality, anxiety, and depression symptoms in anxious adults who screened positive for PTSD. Additionally, this study explored potential mechanisms of action (e.g., cognitive appraisal, perceived exertion, acute changes in affect, arousal, and distress) between exercise and PTSD.

Methods: Thirty trait anxious individuals who screened positive for PTSD were randomly assigned to either a 3-week high intensity resistance training intervention, or a 3-week time-matched attention control group, while blocking for gender. Both groups were required to attend 3 on-site sessions per week, for 3 weeks (i.e., 9 total sessions). Each resistance training session consisted of a 5-minute warm-up, 20 minutes of high intensity resistance training, and a 5-minute cool-down. Each control session consisted of a brief 30-minute educational video on topics not relating to exercise or PTSD. Changes in PTSD symptoms, sleep quality, anxiety and depression were analyzed using repeated measures ANOVA, and potential mechanisms of action were explored with a series of longitudinal mixed-effects regression models. Results: Participants were 73.3% female, with a mean age of 29.1 years (SD = 7.4), and 63.3% identified as a racial minority. Groups did not significantly differ at baseline. There was a Time*Group interaction for hyperarousal symptoms (F = 4.7, p = .04, η2 .18), demonstrating a significantly larger reduction in hyperarousal symptoms for the resistance training group (d = -1.84) relative to the control (d = -1.13).

The Time*Group interaction for avoidance symptoms was not significant (F = 1.7, p = .20, η2 = .08); however, the effect size of resistance training was larger (d = -2.71) than the control (d = -1.16). There was a significant Time*Group interaction for sleep quality (F = 4.7, p = .04, η2 = .19), demonstrating greater improvements in global sleep quality for resistance training (d = -1.06) relative to the control (d = -.15). However, there was no significant effect of Time on PTSD-related sleep disturbances (F = 3.0, p = .1, η2 = .13) nor was there a significant Time*Group interaction (F = .09, p = .80, η2 < .01). Similarly, Time*Group interactions for anxiety (F = 3.5, p = .08, η2 = .14) and depressive symptoms (F = 2.7, p = .12, η2 = .11) were not significant. However, resistance training had a large effect on anxiety (d = -.81), and small effect on depression symptoms (¬d = -.41). Regarding the potential mechanisms of action, changes in cognitive appraisal significantly predicted changes in PTSD symptoms during the resistance training intervention (b = 7.1, SE = 2.9, p = .02).

Similarly, changes in perceived exertion during exercise was a significant predictor of PTSD symptoms over the 3-week intervention period (b = -3.1, SE = 1.2, p = .01). However, changes in affect, arousal, and distress did not significantly predict changes in PTSD (p’s >.05). Conclusion: This is the first randomized attention-controlled trial testing the effects of high intensity resistance training on PTSD symptoms. The overall results support the hypothesis that resistance training can beneficially affect PTSD symptoms and its commonly co-occurring conditions, such as poor sleep quality. Future adequately powered studies are warranted.