Apple Watch could spot COVID-19 symptoms a week before it strikes

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Apple Watch Series 6
Two studies suggest Apple Watch could be a useful diagnostic tool.
Photo: Leander Kahney/Cult of Mac

Smartwatches such as Apple Watch could detect COVID-19 infections a week before the wearer feels sick or would test positive for the novel coronavirus, two medical studies suggest.

Since such devices can identify subtle changes in heart rate that might indicate an early infection, they could spot asymptomatic individuals, who make up a sizable proportion of COVID-19 cases.


Researchers at Mount Sinai Health System in New York and Stanford University in California found that smartwatches could offer a type of early warning system for users during the global pandemic.

If a smartwatch or other device identified certain physiological indicators, for instance, the wearer might decide to avoid contact with others or to seek a COVID-19 test. Early diagnosis likely leads to better patient outcomes.

To date, COVID-19 has killed nearly 2 million people worldwide, according to Johns Hopkins University.

Apple Watch can provide early warning of COVID-19

CBS News writes about the twin studies that offer encouraging news for owners of Apple Watches and similar devices:

“Researchers at Mount Sinai found that the Apple Watch can detect subtle changes in an individual’s heartbeat, which can signal that an individual has the coronavirus, up to seven days before they feel sick or infection is detected through testing…. Specifically, the study analyzed a metric called heart rate variability — the variation in time between each heartbeat — which is also a measure of how well a person’s immune system is working.”

Individuals with COVID-19 reportedly experienced lower heart rate variability (less variation in time between heart beats) than those with no COVID-19. Greater heart rate variability shows that a person’s nervous system is “active, adaptable and more resilient to stress.”

The study was based on almost 300 Mount Sinai health care workers who wore Apple Watches between the end of April and September 2020. Apple didn’t participate in the study.

A second study

Meanwhile, the unrelated Stanford University study found that 81% of coronavirus patients saw a change in resting heart rate up to 9.5 days before COVID-19 symptoms arose. A highly elevated heart rate could therefore help predict the onset of symptoms.

As it is, not enough people wear smartwatches to slow the spread of coronavirus. There are also other, non-COVID reasons why a heart rate might be elevated or for heart rate variability to change. Still, it’s pretty fascinating research that could form the foundation of useful tools going forward.

Apple Watch Series 6 measures blood oxygen levels, too

Similarly, the blood oxygen sensor in Apple Watch Series 6 could spot the “silent hypoxia” that can precede the onset of serious COVID-19 symptoms. “The ability to detect this silent form of hypoxia in COVID-19 patients before they begin to experience shortness of breath is critical for preventing the pneumonia from progressing to a dangerous level,” according to a 2020 study.

That research indicated that even the tech in common smartphones can identify falling blood oxygen levels if utilized properly. An “always on” smartwatch that measures oxygen saturation in the background theoretically should work even better.

All this medical research should serve as a timely reminder that the smartwatches more and more of us wear on our wrists can serve as potentially powerful diagnostic tools.

Source: CBS News