Financial incentives for exercise adherence in adults: systematic review and meta-analysis

Less than 5% of U.S. adults accumulate the required dose of exercise to maintain health. Behavioral economics has stimulated renewed interest in economic-based, population-level health interventions to address this issue. Despite widespread implementation of financial incentive-based public health and workplace wellness policies, the effects of financial incentives on exercise initiation and maintenance in adults remain unclear.

A systematic search of 15 electronic databases for RCTs reporting the impact of financial incentives on exercise-related behaviors and outcomes was conducted in June 2012. A meta-analysis of exercise session attendance among included studies was conducted in April 2013. A qualitative analysis was conducted in February 2013 and structured along eight features of financial incentive design.

Eleven studies were included (N=1453; ages 18-85 years and 50% female). Pooled results favored the incentive condition (z=3.81, p<0.0001). Incentives also exhibited significant, positive effects on exercise in eight of the 11 included studies. One study determined that incentives can sustain exercise for longer periods (>1 year), and two studies found exercise adherence persisted after the incentive was withdrawn. Promising incentive design feature attributes were noted. Assured, or "sure thing," incentives and objective behavioral assessment in particular appear to moderate incentive effectiveness. Previously sedentary adults responded favorably to incentives 100% of the time (n=4).

The effect estimate from the meta-analysis suggests that financial incentives increase exercise session attendance for interventions up to 6 months in duration. Similarly, a simple count of positive (n=8) and null (n=3) effect studies suggests that financial incentives can increase exercise adherence in adults in the short term (<6 months).