Smartwatch Heart Data Has Lower Accuracy For Black Users

A new study suggests that the accuracy of smartwatches and other fitness trackers may be lacking for individuals of color, despite the fact that millions of Americans use these devices to monitor their heart rates.

Studies & Tests

The review of 10 previous studies revealed that, in four of them, wearable sensors were obviously inaccurate when it came to measuring the heart rates of people with darker skin tones. As was discovered in those two earlier investigations, this was the case for some of the devices they tested, but not all.

In light of the fact that Apple Watches, Fitbits, and other "wearables" are used for more than just monitoring physical activity, the researchers find the disparity to be cause for worry. For instance, if a user's heart rate is excessively high or low or shows symptoms of atrial fibrillation (a common cardiac rhythm disorder), the Apple Watch may alert them.

"Now these gadgets are being advertised as a means to monitor your health," says Dr. Daniel Koerber, the study's principal researcher and a resident physician at the University of Alberta in Edmonton, Canada. Thus, inaccurate readings may prompt unneeded trips to the doctor when a person's perceived heart rate is either too high or too low.

Limitations

People with alarming findings should see a doctor, although those with darker skin tones should be mindful of the test's lower accuracy. It's important to "take these readings with a grain of salt," Koerber adds.

In Washington, DC, Koerber presents his results to the American College of Cardiology (ACC). Preliminary studies presented at conferences are often not taken seriously until they have been published in a reputable publication.

Wearable fitness devices are commonplace. Twenty-one percent of Americans, including 26% of Hispanics and 23% of Blacks, reported daily usage of a wristwatch or fitness tracker in a poll conducted by Pew Research in 2021.

The gadgets' inaccuracy on darker skin tones is not a new problem. The problem starts with the fundamental technology that underpins most wearables. Light transmitted through the skin is analyzed for changes in blood volume to calculate the heart rate. Typically, the signal in question will be green.

Melanin, the skin's pigment, absorbs green light more easily due to its shorter wavelength. Further, green light is distinct from the infrared light used in high-tech medical screens. Darker skin filters more green light, reducing the precision of the device's readings.

If It's Not A Help, It's A Hindrance

Devices like this are employed in employee wellness programs, so any discrepancies might have serious consequences. Many businesses provide financial incentives to workers who use fitness trackers, such as paid time off or even reduced health insurance prices.

Manufacturers of affected devices are aware of the problem and, according to their statements, are working to fix it (such as adjusting algorithms). Apple has acknowledged that green light and "intermittent" infrared light are used in their technologies.

At this time, it's not obvious whether improvements to the devices' technology have truly improved their accuracy for people with a darker complexion. It's becoming frustrating that they can't guarantee that all customers will have the same experience with the products they buy.

It is hoped that if these gadgets continue to improve, one day, they will be able to effectively and accurately calculate data across all ethnicities. For the time being, users should be advised that the device's accuracy may not be optimal for their skin tone. You may bring the gadget with you to your next doctor's visit to compare the results.

Clinical Trials

In all, 469 people participated in 10 investigations that formed the basis for the present results. There was a discrepancy in heart rate readings depending on skin tone, although not for everyone. According to Koerber, these results highlight the need for more studies to guarantee that digital technologies are inclusive of all individuals.