Lifestyle Health 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 By Julie Mazziotta Julie Mazziotta Twitter Associate Editor, PEOPLE Health People Editorial Guidelines Published on July 8, 2021 12:29 PM Share Tweet Pin Email Fitbit. Photo: Smith Collection/Gado/Getty As people who dealt with COVID-19 recovered from their illnesses, data from their Fitbits provided a closer look at the long-lasting health effects of the virus, a new study shows. 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. Three-Quarters of Recovered Coronavirus Patients Have Heart Damage Months Later, Study Finds 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. People Who Weren't Hospitalized for COVID Still Have a Higher Risk for Long-Term Illness 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. RELATED VIDEO: Nurse Whose Husband Died of COVID Is on a Door-to-Door Vaccine Crusade: 'I Can Help Save Others' 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. How COVID Affects Your Heart, According to a Cardiologist 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." As information about the coronavirus pandemic rapidly changes, PEOPLE is committed to providing the most recent data in our coverage. Some of the information in this story may have changed after publication. For the latest on COVID-19, readers are encouraged to use online resources from the CDC, WHO and local public health departments. PEOPLE has partnered with GoFundMe to raise money for the COVID-19 Relief Fund, a GoFundMe.org fundraiser to support everything from frontline responders to families in need, as well as organizations helping communities. For more information or to donate, click here.