A study published on July 7, 2021 in JAMA Network Open examined the duration and variation of recovery from acute respiratory illness of participants enrolled in the DETECT (Digital Engagement and Tracking for Early Control and Treatment) study between March 2020 and January 2021. The study found that COVID-19 positive participants took longer to return to baseline for resting heart rate (RHR), sleep and step count, with the greatest effect seen for RHR. All individuals studied reported symptoms of an acute respiratory illness and were tested for COVID-19. Of the 875 participants, 27% tested positive for COVID-19 and 73% tested negative. COVID-19 positive participants did not return to their baseline RHR until an average of 79 days after symptom onset. A small subset of COVID-19 positive individuals (13.7%) did not return to their normal RHR for more than 133 days. Step count and sleep quantity returned to baseline sooner for positive individuals at 32 and 24 days respectively.