Study: Apple Watch Could Flag Potential Covid Cases a Week Sooner Than PCR Tests

Your Apple Watch may be able to flag a case of Covid-19 a week sooner than that good ol’-fashioned nasal swab, according to new research from the Mount Sinai health system.

Research, abridged

The “Warrior Watch Study,” published in the peer-reviewed Journal of Medical Internet Research, tracked several hundred healthcare workers between April and September 2020.

• Each participant’s Apple Watch measured heart rate variability (HRV), which is a key indicator of nervous system stress.
• It’s a “very sensitive way to pick up those changes, that infection that’s occurring, sometimes before people know it,” says Dr. Robert Hirten, who co-led the research with Dr. Zahi Fayad.

“[It’’s] the power of wearable technologies,” Dr. Fayad told us. “Your body is telling you a lot of things, but most of the time you don't have a way to listen to it.”

Big-deal data

This past year, wearables have made more headlines than sourdough starters—from Amazon’s Halo release announcement to Google gobbling up Fitbit.

Most advancements are relatively recent, Dr. Hirten told us. As wearables get more popular, the quality of their data improves significantly, which leads to better biometrics and diagnostics.

Zoom out: These results are “generating momentum” with the power to rebrand wearables, from fitness + niche chronic care uses → predictive care on a population scale, Marissa Schlueter, senior intelligence analyst at CB Insights, told us.

Potential glitches

There are still lots of hurdles to address before the adoption of wearables for healthcare becomes widespread.

Accuracy: A 2020 Duke study found “overall over-reporting of heart rate during low-intensity activity” and accuracy differences between devices.

Sensor limits: Design restrictions place limits on the number of sensors that can be included in a single wearable, which limits the number of use cases a device is good for.

• “As smaller, more powerful batteries—or more efficient ways of powering devices, like via energy harvesting—are developed, we should see the integration of more sensors into wearables,” says Schlueter.

Cost in context: Although wearables are getting cheaper, mass deployment is expensive. Chances are we’ll see more population-scale studies as researchers try to gauge scientific progress—and tech giants try to prove their products.