Activity trackers: Can they really help you get fit?

Robert H. Shmerling, MD

Senior Faculty Editor, Harvard Health Publishing

Follow me on Twitter @RobShmerling

Lately, I’ve been checking the number of steps I take each day. It’s not hard to do. My phone tracks it without me even asking it to. It also tracks the number of flights of stairs I’ve climbed and the number of miles I covered. And there are other options: I could track how often I stand up, how many calories I’ve burned by being active, and how many minutes I’ve engaged in brisk activity.

Even my employer has gotten into the act. As is common in many workplaces, one of our hospital’s wellness programs has organized “walking clubs” with teams comparing and competing with each other based on the number of steps team members take each week. Some companies offer prizes, financial incentives, or reductions in health insurance premiums if an employee participates in such a program.

Why all this monitoring?

Technology we carry around with us — our phones, watches, or other gadgets — allows enormous amounts of data to be collected about us every day. It’s important to keep in mind that there is a purpose to all of this. The point of activity trackers is to become more aware of how much (or how little) activity we’re doing so that we can make positive changes. Since the health benefits of physical activity — and the health risks of being sedentary — are well established, increasing activity is a health priority (or should be) for millions of people. Activity trackers are the first, um, step (sorry, couldn’t resist).

Do activity trackers really improve health?

My guess is that most people take for granted that activity trackers are helpful in promoting more physical activity, but that’s based mostly on assumption. That’s why researchers at Duke-National University of Singapore Medical School designed a study to compare full-time employees who used activity trackers with those who did not. Each of the 800 employees enrolled in the study paid the equivalent of $7 to enroll and then were randomly assigned to one of four groups for one year:

  • use of a Fitbit Zip, a popular clip-on activity tracker (with payment of $3/week to continue in the study regardless of the number of steps taken)
  • a Fitbit plus a cash incentive ($11 for taking 50,000 to 70,000 steps each week, or $22 for more than 70,000 steps/week)
  • a Fitbit plus a payment to a charity (which was larger with increased activity)
  • a control group that did not use an activity tracker; this group also received the $3/week for participation regardless of activity levels.

Researchers monitored more than just the number of steps taken. Study participants also had monitoring of more vigorous exercise and physical activity, weight, blood pressure, fitness levels, and they were asked about quality of life as well.

So, what did they find?

First, the good news

The group receiving the cash incentive increased their daily steps compared to the start of the study. This group was more active than the control group at six months, and 88% of them were still using their Fitbits (compared with about 60% of the Fitbit only and charity incentive groups).

Say it isn’t so!

When incentives stopped, only one in 10 study subjects continued to use the Fitbit. And after a year, with incentives stopped, activity levels fell in the groups receiving an incentive compared to when they started. This is disappointing indeed, especially considering that the participants in this study were probably more motivated than most to focus on their activity levels. They went to the effort and expense of enrolling in the study and agreed to put up with all the monitoring. In addition, most people in the real world probably have no direct financial incentives to maintain a certain level of activity each week.

This study follows another one from the University of Pittsburgh that found less weight loss among young adults who used fitness trackers compared to those who didn’t.

What’s next?

As technology evolves and research provides more information about what works (and what doesn’t), I think we’ll see a new generation of devices that are more customized to individual needs and medical conditions. For example, a person with diabetes might monitor physical activity to provide information about how to coordinate insulin injections and meals.

In addition, activity trackers can do more than simply spit out information about how active you’ve been. A good example comes from another recent study in which activity trackers were incorporated into a competitive game, complete with signed commitments to specific activity goals, an elaborate point system, and reliance on team cooperation and rewards. The study found that those using game-based activity trackers were more active and achieved activity goals more often than those using activity trackers without the game. The study lasted only 12 weeks and improvements waned somewhat after it ended, so the long-term impact of such a program is uncertain.

Physical activity trackers have quickly become a multimillion-dollar product category. I don’t see them going away any time soon. But, to actually get people moving and have a positive impact on health, we’ll probably need to use them in more innovative ways. And if they claim to improve your health, we’ll need high-quality research to back that up.

Related Information: Starting to Exercise


  1. Chris Choi


    This is something that our team is currently working on. We strongly believe that fitness data alone cannot change people’s behavior. We tried to figure out how we would be able to increase the engagement level of our users.

    In our app called SPRYFIT, we combined “money incentive” and “loss aversion” to motivate people. Currently, there are a bunch of games such as 10K steps per day for three weeks challenge.

    At SPRYFIT, users pay an entry fee to join the challenge and exercise not to lose their money. ( Loss Aversion) If the users meet their daily goal for a certain period, they receive their entry fee back plus extra cash coming from those who don’t meet the goal. Based on the past 6 months data, this increased the users’ success rate a lot. In addition, most of our users are joining the challenge continuously.

    We track our users’ data from their wearables devices and fitness apps.

  2. Liz Feinauer

    The idea behind fitness trackers is great. However, if they are going to be beneficial, the individual must have some self-motivation also. One thing that these fitness trackers need to work on in order to really help individuals to get fit is their accuracy of calories burned. In a recent study conducted by Standford, fitness activity trackers were far off from being accurate on measuring energy expenditure. The most accurate device was off by 27% on measuring energy expenditure. The least accurate device was off by 93%. Many individuals may be relying on these trackers to help them determine the amount of calories burned in order to determine how many calories they can consume for the rest of the day. If the devices are not accurate, it is just another way in which they may keep people from getting fit and may make them even less motivated to use them if incentives are not involved.

    Dusheck, J. (2017). Fitness trackers accurately measure heart rate but not calories burned. Retrieved from

  3. Anne Thompson

    In a way, these results are not surprising–studies in psychology have shown that external rewards can actually decrease motivation for an activity that might otherwise be liked. (see Nisbett’s study with kindergarten kids and drawing.)

    The trick is to increase intrinsic motivation, not extrinsic. Old fashioned behaviorism is not particularly effective and can be counterproductive.

    I see no reason why trackers could not be combined with a program to increase intrinsic motivation for exercise. I think they work that way for me (a step counter that I can read easily and a fitbit zip.) I hope researchers will forget giving extrinsic rewards, and design research with some hope of succeeding long term!

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