Even with the addition of financial incentives, regular use of a wearable tracker that monitors and offers feedback on physical activity did not raise exercise levels enough to produce significant health benefits, according to results published in The Lancet Diabetes & Endocrinology.1
Physical inactivity is the fourth leading risk factor for global mortality, according to research published in 2012.2 However, the increasing popularity of activity trackers—1 in 10 US adults owns one of these devices3—may help people achieve recommended levels of exercise and reduce their risk for noncommunicable diseases like diabetes and heart disease. Moreover, employers, insurers, and government agencies are encouraging the use of activity trackers in the hopes of improving the population’s health.4
To determine whether activity trackers combined with financial incentives increase exercise levels, researchers conducted the TRIPPA trial (A Randomized Trial of Economic Incentives to Promote Walking Among Full Time Employees; ClinicalTrials.gov identifier: NCT01855776). A total of 800 employees aged 21 to 65 years from 13 organizations in Singapore were recruited for the study.
Between June 13, 2013, to August 15, 2014, the researchers randomly assigned participants to 1 of 4 groups: control, meaning no tracker or incentives (n=201), use of an activity tracker (Fitbit Zip; n=203), use of the tracker plus charity incentives (n=199), and use of the tracker plus cash incentives (n=197). Both the charity and cash groups were told they could earn up to S$15 (Singapore dollars) per week if they logged between 50,000 and 70,000 steps or S$30 if they logged more than 70,000 steps.
The charity group donated this money to a charity of their choice while the cash group kept the money for themselves. To maintain engagement, the control and activity tracker only groups received S$4 weekly regardless of step count. Incentives ceased after 6 months, but participants were allowed to keep the activity tracker.
The amount of moderate-to-vigorous physical activity served as the primary outcome, and step count, weight, blood pressure, cardiorespiratory fitness, and self-reported quality of life at baseline and 6 and 12 months later were also recorded.
At 6 months, both mean daily steps and moderate-to-vigorous physical activity declined in the control group and remained stable in the charity incentive and activity tracker only groups. In contrast, participants in the cash incentive group experienced a 570-step increase in mean daily steps (95% CI, 210-930; P =.0016) and were 8% (95% CI, 0-17; P =.0458) more likely to meet the 70,000 weekly step target.1 The researchers noted, however, that moderate-to-vigorous physical activity only increased by 22 minutes per week (95% CI, 5-38; P =.0096) for those who were insufficiently active at baseline.1
Additionally, at 6 months, compared with the control group, participants in the cash incentive group recorded 29 more minutes of moderate-to-vigorous physical activity per week (95% CI, 10-47; P =.0024) and those in the charity incentive group recorded 21 more minutes per week (95% CI, 2-39; P =.031).1
There were no significant differences between the control and activity tracker only groups or between the cash and charity incentive groups and the activity tracker only group.
Despite initial increases in physical activity, at 12 months—6 months after incentives were stopped—physical activity declined to near-baseline levels in the cash incentive group. Participants in the activity tracker only group, however, had improved levels of physical activity, logging an additional 16 minutes of moderate-to-vigorous physical activity per week (95% CI, 2-30; P =.0301).1
The researchers reported no improvements in health outcomes at either 6 or 12 months.
“[W]e found no evidence that the device promoted weight loss or improved blood pressure or cardiorespiratory fitness, either with or without financial incentives,” lead study author Eric Finkelstein, PhD, of Duke-NUS Medical School in Singapore, said in a press release.5 “While there was some progress early on, once the incentives were stopped, volunteers did worse than if the incentives had never been offered, and most stopped wearing the trackers.”
In light of their findings, Dr Finkelstein and colleagues hypothesized that the type and length of financial incentive may be crucial to its effectiveness.