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Fitness Trackers May Help Predict Coronavirus Infections

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Key Takeaways

  • A recent study shows analyzing health data from activity trackers can help detect potential cases of COVID-19.
  • Study authors found when combined with symptom data, information about changes in heart rate, sleep, and activity levels helped effectively predict who was likely to have COVID-19.
  • Innovative diagnostic tools like this could help curb the spread of the virus, especially if more volunteers participate.

Fitness trackers have long been hailed as a great source of personal and public health information. From stories of them predicting pregnancies to studies suggesting they can help track flu outbreaks, wearable devices have proven to be a useful tool for medical researchers.

And now, as the country struggles to contain the coronavirus pandemic, a team of scientists are looking at the devices once again, but this time to help them predict COVID-19 infections. 

On Thursday, the Centers for Disease Control and Prevention recorded more than 190,000 new coronavirus cases in the United States, the first time the nation has reported over 150,000 in a single day since the pandemic began.

Researchers from the Scripps Research Translational Institute published the Digital Engagement and Tracking for Early Control and Treatment (DETECT) study on October 29, which looked at whether activity tracker data could accurately detect COVID-19 in symptomatic people.

The study, published in Nature Medicine, was based off nearly 10 weeks of health data (beginning on March 25) from fitness wearables logged in a research app, MyDataHelps. Participants also logged any COVID-19-related symptoms and COVID-19 test results. 

The researchers analyzed three types of data from activity trackers: daily resting heart rate, sleep duration in minutes, and step count. The research team says finding changes in these three metrics are a sign of viral illness or infection.

Kevin Campbell, MD, FACC, a cardiologist in North Carolina,, says people generally have a pretty consistent resting heart rate. When we get sick, especially with a fever, our resting heart rate typically increases significantly—it’s a sign of extra stress on the body as it tries to fight off infection.

“The heart rate to steps ratio will also become abnormal for similar reasons—our resting heart rate is increased and our steps are decreased due to an infection,” Campbell, who was not involved with the study, tells Verywell.

Out of 30,529 participants, 3,811 reported COVID-19 symptoms. Out of those symptomatic users, 54 tested positive for the virus and 279 tested negative. These results told researchers that their model had a nearly 80% accuracy in predicting whether a person who experienced symptoms was likely to have COVID-19. 

Among the study participants, 78.4% used Fitbit devices, 31.2% connected data from the Apple HealthKit, and 8.1% used data from Google Fit (the study allowed people to use more than one device or platform).  

What This Means For You

Researchers are hopeful that fitness trackers can help predict who may come down with COVID-19 by detecting changes in their resting heart rate, daily steps, and sleep patterns. If you already own a smartwatch or wearable device, you may want to consider contributing your health information to help scientists expand their pool of volunteers which will improve research accuracy and help distinguish the coronavirus from other illnesses. 

It’s important to note that the study does have a few limitations, including the low level of self-reported diagnostic test results. The participants were also fairly homogenous: 62% were female and only 12% were 65 older. 

Those who own and wear smartwatches and activity trackers may not reflect certain population groups. The study pointed to a 2020 Pew Research Center survey that found the smallest number of users came from those with the lowest annual earnings.

Campbell also notes most illnesses can produce changes in an individual’s resting heart rate, not just COVID-19. But the results still have value.

“This is not specific to COVID-19,” he says. “It only suggests that a person is likely to be battling some type of infection—it could be bacterial, viral, etc. The point is to identify patients that may have a COVID infection so that they can be referred for testing, and contact tracing early.”

Other Research Supports Fitness Tracker Usage

A similar study led by Michael P. Snyder, PhD, director of the Center for Genomics and Personalized Medicine at Stanford University in Stanford, California, also found encouraging results that showed biometric changes on fitness trackers can help detect COVID-19. 

Snyder’s study discovered 80% of participants had alterations in their heart rate, number of daily steps, or time asleep. His study method also included an alarm system to notify users of possible infection.

“The system will alert people when their resting heart rate goes up and they can self-isolate and see follow-up medical tests if they become positive,” Snyder tells Verywell.

While the results of both studies are promising, Snyder says research like this still needs more data types and volunteers to improve accuracy and distinguish COVID-19 from other illnesses.

According to a press release, the DETECT team is actively recruiting more participants—their goal is to get more than 100,000 people. This, researchers say, will help improve their predictions of who will get sick in symptomatic and asymptomatic people.

Researchers would also like to use data from frontline healthcare workers who are at a high risk of contracting SARS-CoV-2. 

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Article Sources
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  1. Centers for Disease Control and Prevention. CDC COVID data tracker. Trends in number of COVID-19 cases and deaths in the US reported to CDC, by state/territory. Updated November 13, 2020.

  2. Quer G, Radin JM, Gadaleta M. et al. Wearable sensor data and self-reported symptoms for COVID-19 detection. Nat Med (2020). October 29, 2020. doi:10.1038/s41591-020-1123-x

  3. Vogels EA. About one-in-five Americans use a smart watch or fitness tracker. Pew Research Center. Updated January 9, 2020.

  4. Mishra T, Wang M, Metwally AA, et al. Early detection of Covid-19 using a smartwatch. medRxiv 2020. 07.06.20147512. doi:10.1101/2020.07.06.20147512

  5. Scripps Research. Early results from DETECT study suggest fitness trackers and smartwatches can predict COVID-19 infection. Updated October 29, 2020.