Fitness trackers may help in detecting COVID-19

A study of users of the Whoop Strap suggests it can signal signs of possible infection

A fitness tracker from Boston-based Whoop may help identify people with the coronavirus.Shutter2U - stock.adobe.com

Testing for COVID-19 is time-consuming and uncomfortable. But what if there was a convenient device that could alert you to signs of infection and is so comfortable you forget you have it on?

Like, the fitness trackers worn by millions of sports enthusiasts?

Professional golfer Nick Watney was wearing such a device last week, a fitness tracker made by Boston-based Whoop. The device, called Whoop Strap, detected an unexpected spike in Watney’s respiration rate. Sure enough, a standard test confirmed that Watney had contracted COVID-19, forcing him to withdraw from the PGA Tour. Now the PGA is issuing hundreds of Whoop Straps to golfers and caddies.

It’s the latest evidence that fitness trackers could provide early warning of COVID-19 infections. Earlier this week, Whoop said that a new research study from Central Queensland University in Australia found the device, in some cases, was able to identify people with the coronavirus even before they showed any symptoms.

The new study is based on data from 271 people who used the Whoop Strap. Some had tested positive for COVID, and others tested negative but who suffered from symptoms of the disease. The researchers studied weeks worth of stored data showing the respiratory rates of Whoop users at night while they slept. They compared that data to the sleep respiration patterns of known COVID-19 patients.

By measuring increases in the respiratory rates of infected people, the researchers say they identified 80 percent of users who had tested positive for COVID-19. And in 20 percent of those cases, the researchers said they correctly predicted the disease before the user had even begun showing symptoms.

Douglas Johnston, a cardiothoracic surgeon at Cleveland Clinic who reviewed the Whoop study, called it “a very neat way to look at the potential effect of a respiratory virus on an individual.” He said that the results suggest the possibility that the respiratory effect of COVID-19 might be unique to that particular disease, making it easier to distinguish it from other flu-like ailments.

But Johnston warned of one possible limitation of the study. “The people who tend to buy a Whoop device for their own use tend to be a very healthy population,” he said. More research will be needed to determine whether COVID-19 has the same respiratory effects on people who aren’t as physically fit.

The research was released prior to publication and has not been peer-reviewed. Whoop’s chief executive Will Ahmed stressed his company is not touting the Whoop Strap as a medical device. On Wednesday the company announced the launch of an international research project to confirm the value of the Strap as a diagnostic tool, with Harvard Medical School among the participating institutions.

But if the results are confirmed by other scientists, it could give Whoop an early lead in a global race to track COVID cases against the tech companies that dominate the market — Apple, Fitbit, and Garmin.

One in five US adults uses a fitness tracker, according to the Pew Research Center. They’re usually designed to transmit fitness data to the user’s smartphone over a wireless Bluetooth link, and they range in price from about $75 to several hundred dollars. But unlike its competitors, the Whoop Strap itself is free. Instead customers pay $30 a month for membership in a community of health and fitness buffs. The company collects and analyzes such data as heart rate, body temperature, and respiration. Through a smartphone app, members can get personalized information on their physical performance during exercise, at rest, and even when sleeping.

It was one of those members who raised the prospect of using the Whoop gadget as a COVID tracker. Emily Capodilupo, Whoop’s vice president of data science and research, said that in early March, a COVID-infected user in New York posted screen shots of his health data on the social media site Reddit.

One image showed a big spike in his respiration rate.

“To see it go up like 30 percent in this otherwise healthy guy all of a sudden was kind of shocking,” Capodilupo said. “That’s what really turned us on that we could detect something.”

Shortly thereafter, Whoop added a feature to its app that let COVID-infected users identify themselves, so their data could be used for medical research. These users also received an online questionnaire asking about their symptoms. Within 24 hours, hundreds of users had signed up to share their data; today there are thousands.

Jennifer Radin, an epidemiologist at Scripps Research Translational Institute in La Jolla, Calif., noted that the Whoop study is based on only a small sample of infected people. Still, “I think Whoop is one device out of many that could help identify viral illness onset,” she said.

In January, before COVID became a national crisis, Radin published a study of 200,000 Fitbit users, which found that data from the fitness trackers could be used to monitor the spread of flu-like illnesses in the United States.

Today, she and her colleagues are testing a variety of fitness devices as potential COVID trackers. One is a ring called Oura that contains the same kinds of sensors found in fitness monitors and transmits health data to the user’s smartphone. Recent research from West Virginia University found that the Oura ring can predict the onset of COVID symptoms three days in advance with 90 percent accuracy. The National Basketball Association has said it will provide Oura rings to players when the league resumes play at Walt Disney World in Orlando.