February 2017 Issue

Focus on Fitness: Fitness Trackers for Heart Health
By Jennifer Van Pelt, MA
Today's Dietitian
Vol. 19, No. 2, P. 52

As discussed last month, wearables are the top fitness trend for 2017, according to the American College of Sports Medicine. The most common wearables are fitness trackers like those marketed by Fitbit, Garmin, and Jawbone. A range of capabilities and pricing is available. More expensive fitness trackers and the recently introduced smart watches offer more health-related and lifestyle features, such as heart rate monitoring, activity pacing by heart rate, and alerts when you've been sitting too long. These features all facilitate monitoring and improving heart health. However, it's possible to improve heart health with cheaper, basic fitness trackers that provide only daily steps, active minutes, and sleep information. This month, I'll review selected published studies on fitness trackers and provide some guidance on how to use the basic ones such as the Fitbit One, Garmin vívofit 3, and Jawbone UP MOVE.

What Does the Research Say?
Published research on fitness trackers and heart health is currently lacking. Numerous studies have been published on their use for increasing activity and changing health behaviors. A few recent studies include the following:

  • A 2015 randomized controlled trial found that use of a Fitbit increased daily moderate-to-vigorous physical activity more than a pedometer in postmenopausal women.1
  • A 2016 randomized controlled trial found that using the Fitbit One in conjunction with its mobile app that sends activity prompts significantly increased daily steps compared with use of the Fitbit One only.2
  • A 2016 study comparing 133 users of Fitbit, Jawbone, and Nike fitness trackers found that the trackers provided psychological benefits in addition to inducing behavioral changes in exercise activity. Users reported they felt more in control of their exercise regimen and experienced family relationship improvements when relatives joined them in using fitness trackers.3
  • A small 2016 study evaluated fitness trackers in 10 older adults with chronic medical conditions who had never used them before. After 14 weeks of tracker use, participants lost a significant amount of weight and reduced LDL cholesterol. In addition, they reported feeling better and more confident in their ability to exercise.4

Although research on fitness trackers and heart health hasn't yet been published, research does support their use for increasing and maintaining physical activity and supporting health-related behavioral changes. By providing motivation and tools to maintain a healthy level of physical activity, fitness trackers therefore contribute to reducing risk factors for heart disease.

Practical Advice for Use
Wearables are expensive; even the most basic trackers cost at least $50. Getting the most out of wearables also requires use of a mobile app and/or a computer. Clients who aren't yet using a fitness tracker should be encouraged to start with a cheaper basic device rather than a smart watch or high-end fitness tracker. Heart rate monitoring has been touted as necessary for accurate assessment of exercise intensity. While athletes who are training for competition might require advanced heart rate monitoring, the average exerciser doesn't. Using perceived exertion is enough to estimate intensity for most clients.

Heart rate monitoring at rest and during exercise isn't a necessary fitness tracker feature to improve heart health. In fact, the accuracy of this feature on many trackers hasn't been validated, especially for intense exercise.5 The increased cost associated with heart rate monitoring features on a fitness tracker probably isn't worth it at this time. For clients with cardiac conditions who may require heart rate monitoring, a medical device recommended by their physician should be used rather than a fitness tracker. There are wearables available that track blood pressure and function as a portable electrocardiograph.

Keeping track of daily steps and activity intensity by steps per minute can be used to set daily goals to increase physical activity. Most fitness trackers automatically set 10,000 steps per day as a goal. But this number isn't necessarily ideal and should be customized based on a client's activity level. The 10,000 steps value originated in the 1960s when the Japanese pedometer "Manpo-kei" was introduced; its name translates to "10,000 steps meter." Early research on pedometers validated that consistently reaching at least 10,000 steps daily resulted in lower blood pressure and increased aerobic fitness. Setting a daily goal of 10,000 steps may be too high and discouraging to clients just beginning to exercise, and too easy for very active clients. Setting a daily step goal of approximately 2,000 steps more than a client's average daily steps is a good starting point; then the goal can be increased as clients become more fit.

Use of a tracker to reach and exceed daily activity goals can encourage users to exercise regularly and increase daily activity as they progress. Most trackers monitor active and/or very active minutes, which indicate moderate to vigorous exercise necessary to improve heart health and fitness level. Comparing daily active minutes, as well as steps, provides users with a weekly profile of their exercise intensity.

Mobile apps that can be used with fitness trackers provide "coaching" via alerts about activity levels. And some apps allow networking with friends and coworkers for friendly exercise competitions.5 Some employers and health insurance companies use fitness trackers for exercise monitoring and reward users for meeting or exceeding goals with monetary incentives or fitness-related prizes. Using fitness trackers with a network of friends and coworkers not only provides socialization opportunities but also introduces more accountability for maintaining exercise.

Using a fitness tracker for the first time can be an eye-opening experience. Americans in general are very sedentary, and a fitness tracker provides hard evidence of just how little exercise one gets daily. For example, clients with sedentary jobs may get as few as 3,000 steps daily. Setting a step goal with the fitness tracker can motivate them to make minor changes—such as parking farther away from their office building, walking the dog a longer distance, or playing with their children outside—that can help them move more. Continued use provides feedback and motivation for major changes, such as setting aside time for moderate-to-vigorous exercise to increase daily steps and active minutes, and thereby improving heart health in the long run.

For a helpful client infographic on wearables, visit jamanetwork.com/journals/jamacardiology/fullarticle/2513306.

— Jennifer Van Pelt, MA, is a certified group fitness instructor and health care researcher in the Reading, Pennsylvania, area.

1. Cadmus-Bertram LA, Marcus BH, Patterson RE, Parker BA, Morey BL. Randomized trial of a Fitbit-based physical activity intervention for women. Am J Prev Med. 2015;49(3):414-418.

2. Wang JB, Cataldo JK, Ayala GX, et al. Mobile and wearable device features that matter in promoting physical activity. J Mob Technol Med. 2016;5(2):2-11.

3. Karapanos E, Gouveia R, Hassenzahl M, Forlizzi J. Wellbeing in the making: peoples' experiences with wearable activity trackers. Psychol Well Being. 2016;6:4.

4. Gualtieri L, Rosenbluth S, Phillips J. Can a free wearable activity tracker change behavior? The impact of trackers on adults in a physician-led wellness group. JMIR Res Protoc. 2016;5(4):e237.

5. Kaiser DW, Harrington RA, Turakhia MP. Wearable fitness trackers and heart disease. JAMA Cardiol. 2016;1(2):239.