Wrist-worn heart rate monitors have variable accuracy

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Marc Gillinov
Marc Gillinov

Robert Wang (The Heart and Vascular Institute, Cleveland Clinic, Cleveland, USA) and others report in JAMA Cardiology (in the form of a research letter) that wrist-worn heart rate monitors have variable accuracy—noting that “accuracy was best at rest and diminished with exercise”. They add that as “cardiac patients increasingly rely on these monitors to stay within physician-recommended, safe heart rate thresholds during rehabilitation and exercise, appropriate validation of these devices in this group is imperative. Study author Marc Gillinov spoke to Cardiovascular News about their research.

What type of cardiac patients might use a wrist-worn heart rate monitor?

Many patients choose to wear them to monitor their cardiac rehab. We currently do not recommend for or against such monitors.

In your experience, how popular are these types of devices among patients?

Very popular!

What were the key findings of your study?

We found that chest strap, electrode-containing monitors are more accurate than wrist-worn, optically based monitors. The wrist-worn monitors vary in accuracy.

What further research is needed?

We have already completed, and are preparing for publication, studies of people wearing wrist-worn heart rate monitors doing other activities (eg. bicycle, elliptical trainer, etc) than the one we evaluated in the present study (rest and 2mph, 4mph, and 6mph on a treadmill). Studies of the use of such devices in cardiac patients and elite athletes are also underway.

Based on your findings, what advice would you to give a patient who was considering using one of these devices?

If a patient really wants to know their heart rate, then they should use a chest strap monitor. If they use a wrist-worn or other optical heart rate monitor and they have a reading that appears out of range—presuming they feel fine—I would tell them not to panic. The reading is probably incorrect.