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  • Brian Bender, PhD

Wellness Technology Review: Heart Rate Monitors

Quantifying your heart rate pervasively is becoming easier as technology continues to shrink, battery power continues to improve, and wireless technology become evermore ubiquitous.

And with it, new data is available to help refine workouts, personalize fitness regimes, and track progress.

And beyond the world of fitness, heart rate monitors offer the hope of improving diagnostics outside the realm of the clinic. Apple is working on using its Watch-based heart rate monitor to study irregular heart beats and alert patients of atrial fibrillation (the number one cause of stroke) in real-time. In fact, it may have already saved one man’s life!

Other fields are interested, too. Professional sports teams are tracking players’ workouts; the military is interested in tracking soldiers’ health; and even insurance companies are interested in the data.

Wrist-Worn Devices

In a 2017 issue of the Journal of Personalized Medicine, Shcherbina, et al. reviewed the accuracy of several consumer wrist-worn devices regarding heart rate and energy expenditure.

What did she find?

In short, heart rate monitors had an acceptable amount of accuracy.

Energy expenditure calculations, on the other hand, did not.

She and her colleagues reviewed 7 consumer devices:

  • Apple Watch

  • Basis Peak (version 1)

  • FitBit Surge

  • Microsoft Band (version 1)

  • Mio Alpha 2

  • PulseOn

  • Samsung Gear S2

All seven showed decent accuracy with respect to heart rate variability. However, some still performed better than others.

The researchers looked at several conditions during monitoring, including sitting, walking, running, cycling, and at max heart rate.

Across devices and testing conditions, the Apple Watch had the lowest error in heart rate measurements at 2.0%, while the Samsung Gear S2 had the highest at 6.8%. In order, the devices stacked up against each other as follows:

Apple Watch < Basis Peak < FitBit Surge < Microsoft Band < PulseOn < Mio Alpha 2 < Samsung Gear S2

Energy expenditure, on the other hand, varied greatly from an error of 27.4% for the FitBit Surge to 92.6% for the PulseOn.

As for the heart rate monitors, variables like darker skin tone, larger wrist circumference, and higher BMI all correlated with higher error. Nevertheless, these wrist-worn heart rate monitors show an acceptable level of accuracy and continue to improve through both hardware and software updates.


Companies like Athos, Nike, and Adidas, among others, are creating smart clothing with sensors sewn into shirts, sports bras, and other pieces of clothing to monitor heart rate.

As long as the monitor stays tight against your skin, they work well. So just like the sensors and algorithms in watches and other fitness trackers, and chest-strap monitors, they work decently well.

But while some will wear their watch all of the time (including while asleep), your smart clothes will likely be relegated to workouts.


Spree sells a baseball cap (Smartcap) integrated with a heart rate monitor, and Moov goes beyond with its headband, Moov HR Sweat, to track heart rate along with the waveform pattern (think, EKG) using oxygen sensing. Moov’s device is meant to worn only during workouts, but according to one review, stays within 2-5 BPM of an Apple Watch.

For specific workouts, products like the LifeBeam integrate heart rate monitors into your bicycle helmet’s forehead pad and Moov additionally produces a smart swim-cap.


The Oura Ring is a new product slated for a 2018 release date. This ring aims to track sleep, fitness activities, and heart rate all from a titanium ring.

Early comments via ProductHunt appear positive. With many people loath to wear a watch while they sleep, this sleek and subtle device has the potential for better sleep tracking compliance.

As for the accuracy of its heart rate monitor - it’s too early to tell. But as technology is improving and - obviously miniaturizing - across the board it is likely to meet good standards.


Consumer heart rate monitors have gotten quite accurate across the board as sensor accuracy and software algorithms for analyzing data have steadily improved.

Moreover, sensor miniaturization has led to ubiquitous placement in seemingly all items of clothing or accessories that contact skin.

Several pieces of clothing and sports accessories offer options during workouts, and watches and jewelry provide options more akin to pervasive monitoring throughout the entire day.

Other pieces of clothing and new products are constantly entering the market. Take your pick!

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