Inside Fitbit’s Plan to Detect Covid Symptoms With a New Wearable

We talked to the team behind the new Fitbit Sense, a $329 smartwatch dedicated to tracking your health

David Pogue
Published in
10 min readAug 25, 2020


Graphic illustration of a person wearing a Fitbit watch that has a holographic covid coming out of it.
Illustration: Sandro Rybak

The main reason the coronavirus has shut down society isn’t that it’s deadly; it’s that it’s invisible. If you could see the damn particles — as a neon-yellow cloud on someone’s breath, or a neon-yellow patch on a doorknob — you could avoid it, and the disease wouldn’t spread.

Fitbit is in the business of making the invisible visible. From the vibration patterns of your footsteps, they reveal how active you are. From your arm-movement patterns, they determine what exercise you’re performing. From your heart rate and tossing-and-turning frequency, they can graph your sleep stages.

The company’s latest ambition is to expand that detection principle to your overall health. If a smartwatch could learn the patterns of an early Covid-19 infection, for example, it could save your life and thousands of others. Fitbit’s new smartwatch, the Fitbit Sense (announced today and out next month for $329) is the first step.

Like the company’s previous efforts, it’s not a do-everything cellular wonder toy like the Apple Watch. It doesn’t make phone calls or unlock your Mac. Its app store has a few hundred apps, not tens of thousands.

Fitbit’s newest smartwatch is heavily slanted toward biometric measurements. Credit: Fitbit

Instead, it’s primarily dedicated to health and fitness. The Sense is bristling with sensors. They cover one third of its entire surface and include:

Skin thermometer. The entire stainless-steel back, set against your wrist, is part of the new skin-temperature system.

Electrodermal activity (EDA) sensor. This sensor measures your physical stress level.

When you want an EDA measurement, you rest your palm on the watch’s face. Tiny electrodes pass a faint current through your fingers, measuring their impedance.

“As you get stressed out, or upset, or excited, you get these little microsweats,” says Shelten Yuen, Fitbit’s head of research. “Well, sweat is conductive…