Financial Incentives to Promote Physical Activity in Japan: A Rapid Review.

Financial incentives are a promising strategy to promote physical activity. While randomized trials in Western countries have demonstrated short-term effectiveness, evidence from non-Western settings remains limited. This rapid review synthesized evidence from Japan on financial incentive-based interventions considering both individual-level behavioral responses and their use as policy tools implemented by administrative organizations. A systematic search of 4 databases (CiNii Articles, PubMed, Google Scholar, and Ichushi Web) was conducted between May and June 2025, covering English and Japanese studies. Intervention characteristics were described using the TIDieR checklist and step count changes were extracted. Where necessary, healthcare cost savings and return on investment (ROI) were also estimated. Fourteen studies (11 peer-reviewed and 3 gray literature) were included. Most interventions used redeemable points or gift certificates as incentives, with daily values ranging from ¥11 to ¥100. On average, interventions increased daily step counts by 997 steps and reduced annual medical expenditures by ¥28 425, yielding an average ROI of 5.67. Effects were consistent across population subgroups and incentive types. Only 1 study reported post-intervention sustainability, which concluded that step increases were not maintained after receiving the incentive. Low-cost financial incentives have the potential to increase physical activity and reduce healthcare costs in Japan. Further long-term and cost-effectiveness studies are warranted to support sustainable health policy design.