While Fitbit’s wearable devices started out tracking a user’s steps and movement, the company’s newest devices now include sensors that can track body temperature, oxygen levels, and heart rate fluctuations – data that can help detect signs of depression and a range of other diseases. Early studies of the wearable technology suggest that it can even be used to help detect COVID-19 one to two days before symptoms start.

“Our study also reinforces that breathing rate, resting heart rate, and heart rate variability (HRV) are all useful metrics for indicating onset of illness and are best tracked at night, when the body is at rest,” said Conor Heneghan, Director of Research, Algorithms at Fitbit. “With these initial signals identified, we’ll continue our work in developing an algorithm to detect diseases like COVID-19 and focus on expanded research in a real-world environment.”