Wearables like fitness trackers and smartwatches have been a part of our lives for a while now. These devices assist in measuring an individual’s sleeping pattern, walking speed, heart rate, and the number of steps. Could they be of more use? 

In a recent study by the University of Michigan, researchers have revealed that smartwatches could be used to track the severity of infections like COVID and influenza. This is accomplished by analyzing the patient’s heart rate as recorded by the device. Various signals embedded in the heart rate could offer insights into when a person gets infected and how the sickness progresses. 

Participants of the study were drawn from the Intern Health Cohort Study—a research that follows doctors across several locations in the first year of their postgraduate training—and the Roadmap College Student Data Set, a 2020 study that measured the health of students via wearables, self-reported COVID. and its symptoms, along with other public data. Participants of the study included only those with a COVID positive test, symptoms of COVID infection, and wearable data from 50 days prior to and 14 days after the start of symptoms. In all, 43 medical interns and 72 undergraduate and graduate students were included in the study. 

Researchers found that the participants with COVID-19 experienced increased heart rates with each step after the incubation period. Individuals with a cough had an even higher heart rate per step than those without cough. Participants also reported more circadian phase uncertainty (the body’s inability to time daily activities). The authors speculate that this could be an early sign of infection. Researchers also noticed that the daily basal rate of the participants also increased before or on the onset of symptoms.

The fact that biological signals alter during COVID infections means we might be able to identify the healthy and symptomatic periods in people who wear smartwatches.