Using financial incentives to promote physical activity in American Indian adolescents: A randomized controlled trial

Abstract

American Indians (AI) have high prevalence of diabetes in youth and may benefit from increasing physical activity as a strategy to improve metabolic health. We tested whether financial incentives would elicit greater frequency and/or duration of exercise in AI youth at high risk for developing diabetes. Overweight/obese AI boys and girls, 11-20 years old, were instructed to exercise on 3 days/week for 48 weeks at a tribal wellness center. The program was divided into three, 16-week-long phases to test different financial incentive strategies. Within each phase participants were randomly assigned to one of two groups that received different payments for exercise. Phase 1 was designed to test whether the size of the incentive would affect exercise frequency. In Phase 1, the number of exercise sessions did not differ between the group receiving a modest fixed-value payment per exercise session and the group receiving enhanced incentives to exercise more frequently (26 ± 3 versus 28 ± 2 sessions, respectively, p = 0.568). In Phase 2, the provision of an enhanced financial incentive to increase exercise duration resulted longer sessions, as the incentivized and standard payment groups exercised 38 ± 2 versus 29 ± 1 minutes per session (p = 0.002), respectively. In Phase 3, the effect of reducing the incentives on maintenance of exercise behaviors was inconclusive due to high participant withdrawal. Aerobic fitness increased 10% during Phase 1 but was unchanged thereafter. Insulin sensitivity and body composition were unchanged during the study. In conclusion, enhanced financial incentives increased the duration of exercise sessions, but had minimal effects on exercise participation. These results indicate that financial incentives hold promise in motivating previously sedentary, overweight/obese adolescents to exercise longer, but motivating them to sustain an exercise program remains the major challenge.

Trial registration: ClinicalTrials.gov NCT01848353.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. Flow chart showing the number of participants completing Phases 1 and 2.

The Standard group in Phases 1 and 2 received a fixed payment for exercise sessions, while the Incentive group received enhanced payments that were meant to promote either higher exercise frequency (Phase 1) or longer exercise duration (Phase 2).

Fig 2. Exercise behavior in Phases 1 and 2.

In Phase 1 (A & B), there were no differences between the Standard and Incentive payment groups in the distribution of sessions per week or duration per exercise session. In Phase 2 (C & D), the distribution of sessions per week did not differ between groups, but participants in the Incentive group performed more sessions that lasted at least 40 or 60 minutes, and fewer sessions in 20–39 minute range, than did those in the Standard payment group. * p