Exercise for Non-Motor Symptoms of Parkinson's Disease: An Evidence-Based Review of Clinical Trials, Dosing Considerations, and Mechanistic Insights.

Parkinson's disease (PD) is a neurodegenerative disorder characterised primarily by motor symptoms. However, non-motor symptoms (NMS) also substantially affect patients' quality of life. In recent years, exercise therapy has attracted increasing attention as a complementary treatment for PD and is regarded as a promising strategy for alleviating neuropsychiatric symptoms. A substantial body of evidence suggests that exercise improves multiple NMS domains in PD, and this effect may be achieved through several mechanisms. Despite the growing recognition of its benefits, the evidence base is limited by small sample sizes, heterogeneous interventions and inconsistent outcome measures. This underscores the necessity for further research to be conducted into the distinct effects of various forms of exercise. The present review synthesises the clinical evidence relating the impact of different exercise modalities on mood symptoms (anxiety and depression), cognitive dysfunction, sleep disturbances, pain and autonomic dysfunction in PD. It also discusses how exercise parameters such as intensity and duration can regulate NMS, exploring their potential mechanisms and clinical applications. These insights may inform new approaches to the comprehensive management of PD and future therapeutic strategies targeting NMS.