Fitbits Detect Lasting Changes After Covid-19 (nytimes.com) 158
An anonymous reader writes: One in five Americans uses a Fitbit, Apple Watch or other wearable fitness tracker. And over the past year, several studies have suggested that the devices -- which can continually collect data on heart rates, body temperature, physical activity and more -- could help detect early signs of Covid-19 symptoms. Now, research suggests that these wearables can also help track patients' recovery from the disease, providing insight into its long-term effects. In a paper published on Wednesday in the journal JAMA Network Open, researchers studying Fitbit data reported that people who tested positive for Covid-19 displayed behavioral and physiological changes, including an elevated heart rate, that could last for weeks or months. These symptoms lasted longer in people with Covid than in those with other respiratory illnesses, the scientists found.
The new study focuses on a subset of 875 Fitbit-wearing participants who reported a fever, cough, body aches or other symptoms of a respiratory illness and were tested for Covid-19. Of those, 234 people tested positive for the disease. The rest were presumed to have other kinds of infections. Participants in both groups slept more and walked less after they got sick, and their resting heart rates rose. But these changes were more pronounced in people with Covid-19. "There was a much larger change in resting heart rate for individuals who had Covid compared to other viral infections," said Jennifer Radin, an epidemiologist at Scripps who leads the DETECT trial. "We also have a much more drastic change in steps and sleep." The scientists also found that about nine days after participants with Covid first began reporting symptoms, their heart rates dropped. After this dip, which was not observed in those with other illnesses, their heart rates rose again and remained elevated for months. It took 79 days, on average, for their resting heart rates to return to normal, compared with just four days for those in the non-Covid group.
This prolonged heart rate elevation may be a sign that Covid-19 disrupts the autonomic nervous system, which regulates basic physiological processes. The heart palpitations and dizziness reported by many people who are recovering from Covid may be symptoms of this disruption. Sleep and physical activity levels also returned to baseline more slowly in those with Covid-19 compared to those with other ailments, Dr. Radin and her colleagues found. The researchers identified a small subset of people with Covid whose heart rates remained more than five beats per minute above normal one to two months after infection. Nearly 14 percent of those with the disease fell into this category, and their heart rates did not return to normal for more than 133 days, on average. These participants were also significantly more likely to report having had a cough, shortness of breath and body aches during the acute phase of their illness than did other Covid patients.
The new study focuses on a subset of 875 Fitbit-wearing participants who reported a fever, cough, body aches or other symptoms of a respiratory illness and were tested for Covid-19. Of those, 234 people tested positive for the disease. The rest were presumed to have other kinds of infections. Participants in both groups slept more and walked less after they got sick, and their resting heart rates rose. But these changes were more pronounced in people with Covid-19. "There was a much larger change in resting heart rate for individuals who had Covid compared to other viral infections," said Jennifer Radin, an epidemiologist at Scripps who leads the DETECT trial. "We also have a much more drastic change in steps and sleep." The scientists also found that about nine days after participants with Covid first began reporting symptoms, their heart rates dropped. After this dip, which was not observed in those with other illnesses, their heart rates rose again and remained elevated for months. It took 79 days, on average, for their resting heart rates to return to normal, compared with just four days for those in the non-Covid group.
This prolonged heart rate elevation may be a sign that Covid-19 disrupts the autonomic nervous system, which regulates basic physiological processes. The heart palpitations and dizziness reported by many people who are recovering from Covid may be symptoms of this disruption. Sleep and physical activity levels also returned to baseline more slowly in those with Covid-19 compared to those with other ailments, Dr. Radin and her colleagues found. The researchers identified a small subset of people with Covid whose heart rates remained more than five beats per minute above normal one to two months after infection. Nearly 14 percent of those with the disease fell into this category, and their heart rates did not return to normal for more than 133 days, on average. These participants were also significantly more likely to report having had a cough, shortness of breath and body aches during the acute phase of their illness than did other Covid patients.