According to peer-reviewed medical research, the Apple Watch may be able to predict the diagnosis of COVID-19 up to a week before symptom onset or positive test results.

In January, two studies found that the Apple Watch and other wearables may be able to detect COVID-19 infection based on heart rate data collection. And now, the Mount Sinai "Warrior Watch Study" has been published in the peer-reviewed Journal of Medical Internet Research, adding further weight to the findings.

In the Mount Sinai study, approximately 300 healthcare professionals were asked to wear an Apple Watch and use an app to monitor their health over a five-month period (April through September). Participants were also asked to complete daily questionnaires about potential COVID-19 symptoms and other factors such as stress.

The researchers analyzed heart rate variability (HRV), or the interval between heartbeats. The data information was combined with other symptoms reported in association with COVID-19, including fever, pain, dry cough, gastrointestinal disturbances, and taste and smell disorders.

The study found that the Apple watch could detect "subtle changes in an individual's heart rate" up to seven days before the onset of COVID-19 symptoms or a positive test.

One of the study's authors, Rob Hirten, assistant professor at the Icahn School of Medicine at Mount Sinai, told CBS MoneyWatch, "We already knew that heart rate variability markers change as inflammation progresses in the body. Covid is an incredible inflammatory event."

Hilten and the other authors point out that monitoring one's health with an Apple watch may help spread COVID-19. They may be able to identify people who should be quarantined without the need for nasal swab tests.

"Right now, we rely on people saying they are sick or feeling sick, but wearing an Apple Watch could identify people who may be asymptomatic without requiring active user input," says Hilten. 'It's a way to better control infections.'

Mount Sinai's research is ongoing and will also use Apple Watch data to examine the impact of COVID-19 on healthcare professionals, including how sleep and physical activity relate to illness.