Fitbit Data Showed That COVID Survivors Had an Elevated Heart Rate for Months After Diagnosis
Researchers tracked the long-term health changes in hundreds of people who tested positive for COVID-19 and found that symptoms lasted longer than other respiratory illnesses
A group of researchers in California and Michigan who monitored the Fitbit data of hundreds of people who tested positive for COVID-19 found that they had an elevated heart rate for, on average, 79 days, or nearly three months after their initial symptoms. And a small portion of the patients, about 14%, continued to have a heart rate that was 5 beats per minute above normal for more than 133 days, or four and a half months.
The study looked at 875 people who reported having symptoms of a respiratory illness such as fever, cough and body aches. Of that group, 234 people tested positive for COVID-19, and the others were assumed to have another type of infection.
The people in both groups slept more, walked less and saw their resting heart rates go up after the start of their infection, but the change in heart rates lasted far longer in the COVID-19 patients. Those who did not have COVID-19 saw their resting heart rates return to normal after just four days, in comparison.
The COVID-19 patients also experienced an unusual drop in heart rate about nine days after the start of their symptoms, before it rose back up to above average and stayed there for months.
"There was a much larger change in resting heart rate for individuals who had Covid compared to other viral infections," Dr. Jennifer Radin, an epidemiologist at Scripps who is leading the trial, told The New York Times.
Radin said that the COVID-19 patients also took longer than the other people to return to their normal levels of sleep and physical activity.
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The researchers suggested that this data indicates that COVID-19 alters the automatic nervous system, which controls usual body functions like heart.
"Lots of people who get COVID end up getting autonomic dysfunction and a kind of ongoing inflammation, and this may adversely affect their body's ability to regulate their pulse," Radin said.
They hope to do a larger study in the future that monitors the health effects of COVID-19 in patients for a longer period of time.
"We want to kind of do a better job of collecting long-term symptoms so we can compare the physiological changes that we're seeing with symptoms that participants are actually experiencing," Radin said. "So this is really a preliminary study that opens up many other studies down the road."
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