Study shows that apple watch can predict the test results of COVID-19 one week prior.

This study also supports the idea that heart rate changes could be indicative of early signs of COVID-19.
The "Warrior Watch Study" used an Apple Watch and iPhone app and included Mount Sinai staff as participants.
Participants were allowed to use the app to track and gather health data and were also asked to fill out a daily survey to provide direct input on their possible COVID-19 symptoms and other factors like stress.
During the study (April to September), the research team collected data from several hundred healthcare workers. Heart rate variability (HRV), a crucial indicator of pressure on an individual’s nervous system, was the primary biometric signal that the study authors watched.
This information was combined with information on reported COVID-19-related symptoms, including, but not limited to, fever, aches, dry cough, gastrointestinal problems, and loss of taste and smell.
The findings also showed that participants’ HRV patterns returned to normal roughly one to two weeks following their positive tests along with predicting the diagnosis a week ahead.
The study’s authors state that it can help anticipate outcomes and isolate individuals from others who are at risk. Since it provides a means for doing so remotely, caregivers can detect a COVID-19 case without doing a physical test, which can help take precautionary measures and possibly prevent any spread.
The study aims to expand to find what other wearables and their onboard sensors can tell us about other impacts of COVID-19 on the health of care workers and what other factors can be associated with the disease. Source-Medindia