Researchers are exploring how wearables like the WHOOP might help people detect a COVID-19 infection before symptoms begin.

By Korin Miller
April 06, 2020
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Between the lack of widespread coronavirus testing and a growing number of asymptomatic coronavirus infections, tracking the spread of COVID-19—let alone containing it—has been extremely difficult. Reminder: People who are infected can still spread the coronavirus, even if they aren't showing symptoms. In fact, it's now believed that roughly 25 percent of people infected with COVID-19 may not show any symptoms of the illness, Robert Redfield, M.D., director of the Centers for Disease Control and Prevention (CDC), recently told NPR.

In an effort to better identify asymptomatic people with the coronavirus, researchers are now exploring whether wearable fitness trackers—and the health data they measure (heart rate, sleep cycles, etc.)—may provide early clues for users who may be infected with the coronavirus but aren't aware of any obvious symptoms.

The folks behind the fitness tracker WHOOP are partnering with researchers from the Cleveland Clinic and Australia's CQUniversity to study whether there's a link between WHOOP users' respiratory rates and potential COVID-19 infections, according to a press release. (Related: 5 Cool Ways to Use Your Fitness Tracker That You Probably Haven't Thought Of)

ICYDK, respiratory rate refers to the number of times a person breathes per minute at rest, explains Richard Watkins, M.D., an infectious disease physician in Akron, Ohio, and a professor of internal medicine at Northeast Ohio Medical University (who is not involved in the WHOOP study). For context, a normal respiratory rate is between 12 and 20 respirations per minute (RPMs), says Dr. Watkins. Anything above or below that while you're resting (i.e. not working out or running around) is considered abnormal.

How will the WHOOP study work, exactly?

WHOOP is currently collecting data from people already using the fitness tracker who've reported having symptoms of COVID-19. The tracker's accompanying app recently introduced the WHOOP Journal, a new interactive feature that allows users to track a variety of daily behaviors against the physiological health data being collected by the tracker. COVID-19 symptom-tracking, specifically, is included in the WHOOP Journal—meaning users can self-report their coronavirus symptoms and potentially be invited to opt into the fitness tracker's study.

To be clear, WHOOP users who decide to participate in the study are agreeing to share information from their trackers—namely, their respiratory rate leading up to the time they started showing symptoms—with researchers, says Emily Capodilupo, vice president of data science and research at WHOOP. However, only those who can confirm their coronavirus diagnosis (positive or negative) with independent testing are eligible to be part of the study, she explains. At this time, "many of the people who have volunteered for the study haven't been able to access testing," so the number of participants in the study is still TBD, says Capodilupo.

How does it work? WHOOP measures users' respiratory rate by looking at a phenomenon known as respiratory sinus arrhythmia. "When we breathe in, our heart rate increases, and when we breathe out, our heart rate slows down, allowing us to pass blood by the lungs while they are full of oxygen," explains Capodilupo. "We can look at these periodic increases and decreases in heart rate every five or so seconds and pull the respiratory rate off of that cycle." WHOOP has even validated the accuracy of its respiratory rate-tracking in a study conducted by researchers from the University of Arizona. The research, published in the Journal of Clinical Sleep Medicine, showed that the tracker is accurate within one breath per minute. (FYI, though: WHOOP is not considered a medical device.)

For its COVID-19 research, WHOOP will give study participants a daily survey with questions about their symptoms and whether they've been hospitalized, explains Capodilupo. When users indicate via the survey that they no longer have symptoms, they'll receive an exit survey with questions about how they're feeling and confirm whether the results of their COVID-19 test were positive or negative, she says. Since symptoms of the coronavirus can mimic those of the flu and strep, the exit survey will also include questions about whether participants were tested for those conditions too, adds Capodilupo.

"The goal is—once we have this cohort of WHOOP members who have gone through a completed COVID-19 journey—that we will actually have something that no hospital has access to: contextual data prior to the onset of disease," says Capodilupo. In other words, the idea behind the research is to see whether progressive changes in respiratory rate—changes that may not be noticeable to the person themselves but could be detected by their fitness tracker—might indicate a coronavirus infection before the full onset of symptoms, thus helping people with COVID-19 take steps to avoid spreading the illness as early as possible.

The research is in its early stages, but preliminary results (which have yet to undergo peer review) suggest that respiratory rate may indeed increase prior to the onset of coronavirus symptoms, says Greg Roach, Ph.D., head of sleep and circadian physiology research at CQUniversity Australia (who is working on the WHOOP study). "There is a chance [respiratory rate] could be used as a leading indicator of a potential [COVID-19] infection," he explains. "If respiratory rate is found to be a good early indicator of potential COVID-19 infection, it could form part of the information used by medical professionals to target testing. Ultimately, this could help to identify positive cases who would then be quarantined to reduce the likelihood of infecting others."

WHOOP isn't the only fitness tracker looking into this, BTW. The Oura Ring is doing a similar investigation by monitoring 2,000 healthcare workers to track measures like their body temperature, sleep patterns, heart rate, and activity levels. Scientists at Scripps Research Translational Institute, which has used fitness trackers in the past to collect data on the flu, are recruiting people who use any kind of wearable to try to predict clusters of COVID-19 using heart rate, temperature, activity, and sleep data. (Related: Should You Really Be Tracking Everything?)

So, is measuring respiratory rate a good way to tell if you're developing COVID-19?

In general, your respiratory rate tends to be pretty consistent over time, explains Andrew Berman, M.D., a pulmonary and critical medicine expert and professor of medicine at Rutgers New Jersey Medical School (who is not affiliated with the WHOOP study). But there are situations throughout your day when it can increase. "If you're on a treadmill, your respiratory rate will go up," he says, noting that this type of increase wouldn't necessarily indicate anything alarming. For WHOOP's purposes, to ensure it's collecting the most accurate, consistent data, the tracker will look at users' respiratory rate when they're asleep and (hopefully) not doing things like exercising or moving around too much, explains Capodilupo.

Here's where coronavirus comes in: "COVID-19 often causes patients to feel short of breath, which causes them to breathe faster," explains Dr. Watkins. And, when you breathe faster, your respiratory rate goes up, he says. "COVID-19 may cause an increase in respiratory rate because it presents as a lower-respiratory tract infection," adds Roach. So, in theory, measuring respiratory rate could provide clues about a possible COVID-19 infection. (Related: Should You Start Making and Wearing DIY Masks to Protect Against the Coronavirus?)

But changes in respiratory rate aren't specific to COVID-19, note Roach and Dr. Berman. "Respiratory rate could go up with other conditions like pneumonia," says Dr. Berman. It could also go up as a result of bronchitis or certain strains of the flu, adds Roach. It can even go up with anxiety, which plenty of people are experiencing right now. However, something less severe, like the common cold, typically won't make your respiratory rate go up, says Dr. Watkins. "By using the WHOOP data to compare physiological changes associated with different types of health conditions, we may be able to determine whether respiratory rate could be used as an early indicator to discriminate between COVID-19 and other illnesses," explains Roach.

That said, when someone is sick with any respiratory illness (not just the novel coronavirus), they don't typically experience a massive jump in respiratory rate, says Dr. Berman. It could simply be that they have two more breaths or so per minute—a metric that's still detectable by in-depth data analyses, but maybe not by the person themselves, he explains.

Bottom line: A sudden change in your resting respiratory rate could mean you have COVID-19—or it could mean you're sick with something else, or it could mean you're experiencing anxiety. "It's data that needs to be interpreted," says Dr. Berman. So, it's something, but certainly not everything.

How else can you track respiratory rate?

Of course, not everyone has a fitness tracker, and not everyone can afford one that costs as much as WHOOP (which will set you back anywhere from $180 to more than $300, with a $30 monthly membership). FWIW, other smart products like Garmin watches, Fitbits, and Apple watches can track respiratory rate, too.

Technically you can also try counting your respiratory rate on your own, but it's pretty tough; you might try to control your breathing once you start counting, which can throw things off, Dr. Berman points out. You could ask a loved one to count for you (and to try to do it when you're not paying attention) to attempt to get more accuracy, suggests Dr. Watkins.

Overall, Dr. Watkins recommends just keeping tabs on how you feel when it comes to detecting symptoms of COVID-19. Refresher: The main coronavirus symptoms are fever, cough, and shortness of breath—though other symptoms like diarrhea and loss of taste and smell have been reported, too. (Here's what to do if you think you have the coronavirus.)

Ultimately, Dr. Watkins says it's best to continue to wash your hands regularly with soap and water and practice social distancing—which, BTW, are things you should do regardless of whether you wear a fitness tracker.

The information in this story is accurate as of press time. As updates about coronavirus COVID-19 continue to evolve, it’s possible that some information and recommendations in this story have changed since initial publication. We encourage you to check in regularly with resources such as the CDC, the WHO, and your local public health department for the most up-to-date data and recommendations.

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