The Role of Physical Activity in Opioid Substitution Therapy: A Systematic Review of Interventional and Observational Studies.

Background: Use of physical activity in the treatment and follow-up of people receiving opioid substitution therapy is an understudied area of research. Therefore, the objective of this systematic review was to synthesize the currently available research on the role of physical activity in opioid substitution therapy and proper adaptions for the group. Methods: A systematic search was performed on PsycINFO, EMBASE, MEDLINE, CINAHL, and Web of Science until September 2021 (PROSPERO-reg.no: CRD42020109873). The inclusion criteria were studies involving physical activity interventions for opioid substitution patients. Reference lists of relevant studies were screened to identify additional relevant studies. Data extracted were compiled into tables and descriptively presented. Results: The search yielded 2105 unique records. A total of 10 studies were included, whose methodological quality ranged from satisfactory to very good. Study quality was assessed using a 7-/8-point quality score. The agreement between the reviewers, assessed with Cohen's kappa, was 0.91. Overall, the results suggest that physical activity increases physical fitness of patients in opioid substitution therapy and decreases substance use. The minority of studies in this field are of high quality with sufficient power. Conclusions: The findings of this systematic review suggest beneficial effects of physical activity on physical fitness, substance use, and mental health for patients in opioid substitution therapy. Although the findings are quite consistent across studies, high-quality studies and sufficiently powered clinical trials are needed to confirm and validate the findings and to conclude on the degree of impact.