Fitness Tracker Study Shows Why Paying People to Exercise Doesn't Work

Each day, millions of office workers are paid to sit at their desks all day. Now that we know sedentary life is linked to harmful health consequences, some scientists are coming up with creative incentives to improve people’s health. For instance, What if we actually paid people to be active?

It turns out you can pay people to take slightly more steps each day, going by the results of a study published Friday in JAMA Open Network. Overall, people who received a constant payout of $.00020 per step (which works out to 50 cents for every 10,000 steps) walked an average of 306.7 more steps each day than those in a control group.

But unfortunately, the effects were short-lived: Two weeks after the incentive ended, people were back to their old habits. That doesn’t bode well for using cash to create long-term habit change. But the authors, led by Chethan Bachireddy, M.D., M.Sc., an associate clinical professor of internal medicine at Virginia Commonwealth University, were able to show that setting up the right payment scheme can change how many additional steps people take, and how long they keep up that change — suggesting that there may be ways to fix the long-term issues in the future.

What’s the Best Way to Pay People to Exercise?

Working with 3,515 participants who all wore commercial fitness trackers, this team tried to design the perfect monetary incentive to get people to take more steps each day.

They came up with three scenarios:

In one scenario, 879 participants received a constant payout over two weeks — a going rate of $0.00020 per step ($2 for 10,000 steps). In the second, 881 people were offered increasing incentives. They started at a rate of $0.00005 per step (50 cents for 10,000 steps), but over two weeks that rate increased to $.00035 ($3.50 for 10,000 steps). In the third condition, people received less and less money over the course of two weeks.

Overall, participants walked more when they were in the constant payout group. They walked an average of 306.7 steps more per day compared to the other participants. People in the decreasing condition logged a modest increase of 96.9 steps each day, and people in the increasing condition saw no significant changes in step count compared to the control group.

These results painted a clear picture: The constant payout worked significantly better than both the increasing incentives and the decreasing ones. Those individuals also earned slightly more money overall: The constant incentive group earned $15.48 over two weeks, whereas the increasing and decreasing incentive groups earned $14.54 and $14.67, respectively.

But in the paper, the authors suggest that it wasn’t this modest amount of money that made them walk more. They say the constant payout could have just been easier to remember. But the change may also have been driven by participants’ attitudes toward the payout scheme itself:

“In the other disbursement strategies, getting paid different amounts for doing the same activity may have been confusing, or even felt unfair, potentially contributing to the relative ineffectiveness of those strategies,” they write.

Can You Get the Habit to Stick?

The constant payout did have another upside. Once the incentive ended, people in the constant condition took 329.5 more steps than controls in the first week without getting paid, and 315 more in the second week after the trial was over. But by the third week, the effects had dissipated.

This pattern points to a problem with using money to entice people to exercise: Habits don’t necessarily stick in the long term. This, as these authors note, fits alongside several other studies showing that financial incentives to exercise may not create lasting changes in behavior.

However, there is evidence that behavior change can last slightly longer than the two weeks seen in this study. For example, a meta-analysis published in JAMA in 2017 noted that financial incentives increase exercise session attendance by 11.5 percent on average for a duration of about four to 26 weeks — but they also offered far larger incentives than this study did. Even in that study though, the authors noted that we still don’t know whether money is enough to really get people to stick to the habit for more than a six months.

Writing in an accompanying commentary, Brian Elbel, Ph.D., an associate professor of population health at NYU, argued that in the future, we might be able to fix the long-term problem by offering people a bit more money, but that even this idea is on tenuous ground.

“Future research may find greater success in promoting long-term intervention effects by tweaking the authors’ design (eg, increasing the size and duration of the incentive),” he writes. “However, it is also possible that financial incentives, regardless of how they are delivered, may not be an adequate approach to motivating sustained behavior change.”

Although this paper presents some evidence that you can pay people to get moving, they’ve run into a recurring problem. Money is a good way to get people started, but it’s not enough to make people really change their minds.

Partial Abstract:

Design, Setting, and Participants: A 2-week randomized clinical trial was conducted from June 2 to 15, 2014, using an online platform that automatically records daily steps of pedometer- wearing users and awards points redeemable for cash. The study population comprised 3515 adult users of the online platform in the lower 70th percentile of steps taken among all users before treatment. Data analyses were performed from August 20, 2014, to February 1, 2018. Analysis was performed on an intent-to-treat basis.

Interventions: Participants were randomized to either a control group or to 1 of 3 intervention groups during the 2 weeks of the study. Participants in the control group received a constant daily rate of $0.00001 per step. The 3 intervention groups received a 20-fold incentive increase ($0.00020 per step) distributed differently during the 2 weeks of the study: at a constant, increasing, or decreasing rate. Reminder emails explaining incentive schedules were sent the day before the intervention and halfway through the 2-week intervention.

Main Outcomes and Measures: Change in mean daily steps during the 2-week intervention and 3 weeks after the intervention. The study had 80% power to detect a difference of 280 steps per day during the intervention at α = .05.

Results: The study included 3515 participants (879 in the control condition, 879 in the constant incentive condition, 881 in the increasing incentive condition, and 876 in the decreasing incentive condition). During the intervention, compared with participants in the control group, participants receiving constant incentives logged 306.7 more steps per day (95% CI, 91.5-521.9 steps; P = .005), those receiving decreasing incentives logged 96.9 more steps per day (95% CI, 15.3-178.5 steps;P = .02), and those receiving increasing incentives logged no significant change in steps per day (1.5 steps per day; 95% CI, −81.6 to 84.7 steps; P = .97). One week after the intervention, compared with participants in the control group, only participants receiving constant incentives logged significantly more steps per day (329.5; 95% CI, 20.6-638.4; P = .04). Two and 3 weeks after the intervention, there were no significant differences compared with participants in the control group. Overall, for each $1 spent, participants in the constant incentives group logged 475.4 more steps than those in the increasing incentives group and 429.3 more steps than those in the decreasing incentives group.