Fitbit Sense Brings ECG and Stress Sensing to Your Wrist

Fitbit’s new flagship, the Sense, started shipping this week at $329, and it’s the most medically-minded thing the company has ever put on a wrist. The headline feature is an ECG app that can generate a single-lead electrocardiogram reading in about 30 seconds, checking for signs of atrial fibrillation. That puts Fitbit in the same territory Apple Watch has occupied since Series 4, and it’s a meaningful move for a company that’s built its identity on step counts and sleep scores rather than clinical-adjacent tools.

More interesting to me, though, is the electrodermal activity (EDA) sensor — Fitbit is calling it a first-of-its-kind feature for a mainstream wearable. It works by measuring tiny changes in the sweat level on your skin, which correlates with your body’s stress response. You place your palm over the watch face for a couple of minutes, and the app scores how calm or reactive your body appears to be in that moment. It’s not going to diagnose anxiety, but as a nudge toward noticing your own stress patterns over weeks, it’s a genuinely novel use of wearable sensors.

Rounding out the sensor suite is continuous skin-temperature tracking, which Fitbit is positioning as a way to spot deviations from your personal baseline — useful for things like flagging a fever coming on, or noticing shifts tied to a menstrual cycle, rather than giving you an absolute number you’d compare to a thermometer reading.

Not just about the sensors

Sense also gets a redesigned aluminum case, a bigger AMOLED display, and Fitbit’s usual strengths in battery life and sleep tracking, which the company has quietly gotten very good at over the years. It’s launching alongside two cheaper siblings: the Versa 3, which inherits some of Sense’s smartwatch features like built-in GPS and Alexa/Google Assistant support without the medical sensors, and the Inspire 2, a slim fitness band for people who just want step and heart-rate tracking without the bulk.

The timing here is hard to ignore. Google announced plans to acquire Fitbit late last year, and that deal is still winding its way through regulatory review in multiple countries. Whatever happens with the acquisition, Fitbit is clearly not sitting still in the meantime — this is a genuine expansion of what the hardware can sense, not just a spec bump.

The obvious comparison point is Apple Watch, which has ECG and irregular-rhythm notifications already, plus fall detection and blood-oxygen sensing on the newest models. Fitbit’s answer is to lean into cross-platform support (Sense works with both iOS and Android, same as always) and to be first to market with stress sensing, which no other major wearable currently offers. Whether EDA readings turn out to be actionable or just another number to glance at and forget is the real open question. I’d want to live with one for a few weeks before deciding if it changes how I think about a stressful day, but as a hardware move, this is Fitbit swinging harder than it has in years.