Therapeutic potential of exercise in post-traumatic stress disorder and underlying mechanisms: living systematic review of studies with ongoing evidence surveillance

Background

Exercise may be an effective adjunct to psychotherapy for post-traumatic stress disorder (PTSD), but its biopsychosocial mechanisms remain poorly understood. This co-produced living systematic review synthesises evidence from human and non-human studies on the therapeutic effects and underlying mechanisms of exercise in post-traumatic stress disorder.

Methods

This is a prospectively maintained living systematic review with ongoing evidence surveillance and periodic updating. Following the initial searches of multiple electronic databases conducted in 2023, literature searches are updated every three months in accordance with the living systematic review protocol. The next scheduled search update is due in October 2026. Newly identified eligible studies are incorporated into the living evidence base, with the quantitative synthesis updated when sufficient new data become available. Newly identified records undergo duplicate screening, data extraction, and risk-of-bias assessment, with eligible studies incorporated into the living evidence base. Meta-analyses are updated when new studies contribute relevant outcome data.

Controlled human and non-human studies were eligible. The primary outcome for human studies was post-traumatic stress disorder symptom severity, while non-human outcomes included freezing behaviour, fear memory, fear generalisation, startle response, and locomotion. Data were synthesised using random effects meta-analysis.

Results

At the most recent living update, three additional studies met the eligibility criteria. However, the new evidence was insufficient to warrant a new review iteration or update the quantitative synthesis. The meta-analysis therefore remained unchanged, comprising 11 human and 14 non human studies. The next scheduled search update is due in October 2026.

Human studies showed that exercise was not associated with improvement in post-traumatic stress disorder symptom severity compared with control (standardised mean difference [SMD] −0.08, 95% confidence interval [CI] −0.24 to 0.07). High intensity exercise reduced post-traumatic stress disorder symptom scores more than moderate intensity exercise. There were insufficient data to examine effects on functional impairment, post-traumatic stress disorder symptom clusters, and post-traumatic stress disorder remission. Only three studies, all at high risk of bias, examined mechanisms of exercise, with inconclusive findings.

Non-human studies showed that exercise was associated with improvements across behavioural outcomes, including locomotor activity (SMD 1.30, 95% CI 0.74 to 1.87; 14 studies), and with changes in several neurobiological markers, including increased brain-derived neurotrophic factor (SMD 1.79, 95% CI 0.56 to 3.01).

Conclusions

Current evidence from non-human studies supports beneficial behavioural and neurobiological effects of exercise, whereas evidence from human studies remains limited and inconclusive. Non-human findings suggest that brain-derived neurotrophic factor may be one pathway through which exercise exerts its effects, although corresponding mechanistic evidence in humans remains sparse. The most recent living update did not identify any new eligible studies, indicating that the current evidence and conclusions remain unchanged. Continued surveillance will allow emerging evidence to be incorporated as it becomes available. More rigorous human trials incorporating mechanistic outcomes are needed.

References

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