Last year, when the country’s COVID-19 cases increased and tests were in short supply, some researchers wondered if a new approach to disease surveillance could be on the wrists of Americans.
One in five Americans uses a Fitbit, Apple Watch or other durable training track. And over the past year, several studies have suggested that the devices – which can continuously collect data on heart rate, body temperature, physical activity and more – can help detect early signs of COVID-19 symptoms.
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Now, research suggests that these portable drugs may also help track patients’ recovery from the disease, and provide insight into its long-term effects.
In a paper published Wednesday in the journal JAMA Network Open, researchers studying Fitbit data reported that people who tested positive for COVID-19 showed behavioral and physiological changes, including elevated heart rate, which can last for weeks or months. These symptoms lasted longer in people with COVID than in those with other respiratory diseases, the researchers found.
“This was an interesting study, and I think it’s important,” said Dr. Robert Hirten, a gastroenterologist and portable expert at the Icahn School of Medicine on Mount Sinai, who was not involved in the new work. “Portable devices allow us to be able to monitor humans in a discreet way over long periods of time to see, in an objective way, how the virus has affected them?”
The results are from the Digital Engagement and Tracking for Early Control and Treatment (DETECT) study conducted by researchers at the Scripps Research Translational Institute in La Jolla, California. From 25 March 2020 to 24 January 2021, more than 37,000 people registered in the trial.
Participants downloaded MyDataHelp’s research app and agreed to share data from their Fitbit, Apple Watch or other portable devices. They also used the app to report disease symptoms and the results of any COVID-19 tests.
In October, the same researchers in Nature Medicine reported that when they combined portable data with self-reported symptoms, they were able to detect COVID-19 cases more accurately than when they analyzed the symptoms alone.
But the data, the researchers understood, could also help them track what happened to humans after the worst disease had passed. People recovering from COVID have reported a wide range of lasting health effects, including fatigue, “brain fog”, shortness of breath, headaches, depression, palpitations and chest pain. (These lingering effects are often known as long COVID.)
The new study focuses on a subset of 875 Fitbit-bearing participants who reported fever, cough, body pain or other symptoms of respiratory disease and were tested for COVID-19. Of them, 234 people tested positive for the disease. The rest were thought to have other types of infections.
The participants in both groups slept more and walked less after they became ill, and their resting heart rate increased. However, these changes were more pronounced in people with COVID-19. “It was a much larger change in resting heart rate for people who had COVID compared to other viral infections,” said Jennifer Radin, a public health researcher at Scripps who is leading the DETECT study. “We also have a much more drastic change in steps and sleep.”
The researchers also found that approximately nine days after participants with COVID first started reporting symptoms, their heart rate dropped. After this dip, which was not observed in those with other diseases, the heart rate rose again and remained elevated for several months. It took an average of 79 days for their resting heart rate to return to normal, compared to only four days for those in the non-COVID group.
This prolonged increase in heart rate may be a sign that COVID-19 is disrupting the autonomic nervous system, which regulates basic physiological processes. Palpitations and dizziness reported by many people recovering from COVID may be symptoms of this disorder.
“Many people who get COVID get autonomic dysfunction and a kind of ongoing inflammation, and this can affect the body’s ability to regulate the pulse negatively,” said Radin.
Radin and her colleagues found that sleep and physical activity levels also slowed down to baseline in those with COVID-19.
The researchers identified a small subset of people with COVID whose heart rate remained more than five beats per minute above normal one to two months after infection. Almost 14% of those with the disease fell into this category, and the heart rate did not return to normal for more than 133 days on average.
These participants also reported being significantly more likely to have had cough, shortness of breath and body pain in the acute phase of the disease than other COVID patients.
One limitation of the study is that it did not ask participants to continue reporting the symptoms in the weeks and months after they first became ill. But the researchers plan to ask volunteers to do so in future research.
“We want to do a better job of collecting long-term symptoms so that we can compare the physiological changes we see with symptoms that participants are actually experiencing,” Radin said. “So this is really a feasibility study that opens up a lot of other studies along the way.”
In February, the National Institutes of Health announced that it would provide $ 1.15 billion over the next four years to fund long-term COVID research. The new study highlights the role that wearables can play in that research, Hirten said: “Combining this type of technique with other studies being done and looking at this question of long-term symptoms can really provide a nice objective insight into what happens to people. . “
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