Everyday smartwatches could be used to detect onset of Covid-19

Using a smartwatch's heart rate sensors could also be used to detect other diseases such as influenza. The approach could also help to track disease at home or when medical resources are scarce, such as during a pandemic or in developing countries.

The researchers discovered new signals embedded in heart rate data indicating when individuals were infected with Covid and how sick they became.

They found that individuals with Covid experienced an increase in heart rate per step after the onset of symptoms, while those with a cough also had a much higher heart rate per step than those without a cough.

“We found that Covid dampened biological timekeeping signals, changed how your heart rate responds to activity, altered basal heart rate and caused stress signals,” said researcher professor Daniel Forger. “What we realised was knowledge of physiology, how the body works and mathematics can help us get more information from these wearables.”

The researchers found that these measures were significantly altered and could show when smartwatch wearers were symptomatic.

“There’s been some previous work on understanding disease through wearable heart rate data, but I think we really take a different approach by focusing on decomposing the heart rate signal into multiple different components to take a multidimensional view of heart rate,” said Caleb Mayer, a doctoral student.

“All of these components are based on different physiological systems. This really gives us additional information about disease progression and understanding how disease impacts these different physiological systems over time.”

The wearable data for the study was acquired using Fitbits, self-reported Covid-19 diagnoses and symptom information, plus publicly available data.

The analysis included individuals who reported a Covid-positive test, symptoms and had wearable data from 50 days before symptom onset to 14 days after.

As well as the aforementioned heart rate data, they were also able to track circadian rhythms – the body’s inability to time daily events – which increased around Covid symptom onset. Because this measure relates to the strength and consistency of the circadian component of the heart rate rhythm, this uncertainty may correspond to early signs of infection.

“The global outbreak of the SARS-CoV-2 virus imposed important public health measures, which impacted our daily lives,” said Sung Won Choi, associate professor of paediatrics. “However, during this historical event in time, mobile technology offered enormous capabilities - the ability to monitor and collect physiological data longitudinally from individuals noninvasively and remotely.”

The researchers believe their work establishes that algorithms can be used to understand illnesses’ impact on heart rate physiology, which can form the basis for medical professionals who could deploy the use of wearables in health care.

Future work will focus on whether the findings reflect the effects of Covid-19 only or whether these effects will persist in other illnesses.