Fitbit Sense review

The $329 Fitbit Sense was the most ambitious smartwatch yet when it first debuted. At the time, it was more ambitious than the Apple Watch 6 or the Samsung Galaxy Watch 3. That’s because the Sense has not just an FDA-approved ECG sensor and blood oxygen reading but the ability to measure electrodermal activity and skin temperature.

As I found during my Fitbit Sense review, these new features are designed not to give you a sense of impending doom, but rather a better idea of how you’re doing. That’s why the Fitbit Sense was one of the best smartwatches and best fitness trackers you can buy. 

It's since been replaced by the Fitbit Sense 2, which features an upgraded design, interface and EDA sensor. The original Sense could be a good buy on sale as retailers clear stock, but the latest fitness-tracking technology is now found in the Sense 2.

• How to set up Fitbit Sense and Fitbit Versa 3

Fitbit Sense review: Price and release date

The Fitbit Sense is available now for $329. You can purchase the watch with a black case and black band, or a gold case with a white band.

Those who haven’t already subscribed or used Fitbit Premium will also receive a 6-month trial for Fitbit Premium ($9.99/month, $79.99/year), which includes advanced sleep metrics, guided programs, a wellness report, and video workouts. I’ll share more on Fitbit Premium later in this review. 

Fitbit Sense review: Design and display

Made of stainless steel, the Sense is small and light, making it comfortable to wear both day and night.  When placed next to the Fitbit Versa 2, the Sense is roughly the same size, but has more rounded sides — it’s a more circular squircle. The right side of the case has a small touch-sensitive solid-state sensor that acts as a button, and causes the watch to buzz slightly when pressed. We explain more about the new button in our Fitbit Versa 3 review.

The Sense comes with a silicone Infinity Band strap that I found a bit fussy to strap on my wrist. Fortunately, it’s easy to switch out the bands.

I was really impressed with the Sense’s AMOLED display. While not as high-resolution as the Apple Watch 6, it was bright, colorful, and crisp, and easy to read even outdoors. The screen has three different brightness settings, and you can either adjust the timeout or set it to always-on (which reduces the battery life to about two days). 

Fitbit Sense review: Health features

Compared to all the best Fitbits, Apple Watch 6 and the Samsung Galaxy Watch 3, the Fitbit Sense is the most ambitious when it comes to new health features. The EDA and skin temperature sensor are unique to Fitbit, and are meant to give you a better understanding of just how you’re doing. It remains to be seen how useful these metrics are, but Fitbit deserves some credit for trying something new.

EDA sensor

I don’t need a watch to tell me I’m stressed. But, the Sense will quantify how stressed you are, not just based on how you feel after doom scrolling on Twitter, but also your heart rate, sleep, and activity levels. You can also take an EDA scan, which measures your electrodermal activity, and then factors in your other metrics. After, it asks you how you’re feeling, and gives you the option of taking a guided meditation session to help you calm down.  

Skin temperature

Similar to its blood oxygen and EDA sensor, the Sense’s skin temperature monitor is meant to provide a general sense of your overall health, but is not a primary indicator of any medical condition. Like the SpO2 sensor, you have to wear the Sense while you’re sleeping for it to get a reading; it takes three consecutive nights for the watch to get a baseline reading. A higher or lower skin temperature could mean anything from the onset of an illness or pregnancy, or something as simple as your room was warmer or cooler than the night before. 

ECG sensor

The third smartwatch to receive FDA approval for its ECG app (the Apple Watch 6 and the Samsung Galaxy Watch 3 being the other two), the Fitbit Sense can look at your heartbeat to see if there’s any irregular activity or signs of atrial fibrillation. 

In order to use the ECG app, you have to go through several pages acknowledging that only a doctor can diagnose aFib, and that you’re 22 years or older, don’t have a pacemaker and understand that the assessment isn’t a medical diagnosis. 

After, you open the ECG app on the Sense, place your thumb and forefinger at either corner, and wait 20 seconds. After, the app tells you if you have a regular or irregular heartbeat, or if the test was inconclusive. It worked pretty well for me—my ticker is just fine, according to the app.

SpO2 sensor

With the onset of the novel coronavirus, blood oxygen monitoring has gained a lot of attention as it could be an early warning sign of Covid-19. Unlike the FDA-approved medical devices that clip on to the end of your finger and shine light from one side to the other (known as a transmissive sensor), the Fitbit Sense, as well as the Apple Watch 6 and various Garmin watches, use what’s known as a reflective sensor. While they also shine a light into your skin, these sensors look for reflections that bounce back. 

Partly because reflective sensors are less accurate than transmissive sensors, the Sense, Apple Watch, and all other wearables are not FDA-approved, so their readings should be taken with a grain of salt. In fact, many Apple Watch reviewers have reported wildly-fluctuating readings. 

The Sense proved pretty accurate in my tests. The same day it recorded my blood oxygen levels at 96 percent, I went to the doctor’s office for a Covid test; as part of the test, my blood oxygen was measured at 98 percent. It’s not a huge difference, but considering that a healthy blood oxygen reading is 95 percent and higher, there’s little room for error.

Unlike the Apple Watch and various Garmin devices, the Fitbit Sense doesn’t let you perform spot checks of your blood oxygen saturation. Rather, it takes a reading while you’re sleeping. It’s probably better this way, so you’re not constantly checking. 

Initially, you had to use a specific Spo2 watchface while you were sleeping in order to get this reading, but an update to the Sense's firmware now lets you use any watchface you want. Fitbit says it will add seven new watchfaces with SpO2 data by the end of the year.  

Fitbit Sense review: Fitness features

Of course, with GPS and a heart rate monitor, the Fitbit Sense is meant for fitness, too. I took the Sense on a few runs around my neighborhood; on the first run, it took the Sense’s GPS about a minute to acquire a signal; on subsequent runs, it locked on in about 30 seconds, keeping up with the best running watches around.

During the run, the Sense’s GPS and heart rate monitor were accurate and fast, and it was easy to read even when on the move. The Sense has a bunch of other niceties, including the ability to customize what’s on the screen as you’re running, setting the screen to Always-on while you’re exercising, Auto-pause, and Run Detect.

The watch can also track biking, Bootcamp, circuit training, elliptical, golf, hiking, interval workouts, kickboxing, martial arts, Pilates, spin, swim, tennis, treadmill, yoga, and more.

Fitbit Sense review: Sleep tracking

The first few nights I wore the Sense, its sleep tracking proved erratic, sometimes logging that I didn’t fall asleep until 2:30 in the morning, and other nights breaking up my sleep into two parts. You’re able to edit your sleep logs after the fact, but if you do that, you don’t get a sleep score. I then adjusted the sensitivity to Sensitive from Normal, and one night, the Sense was able to accurately record my zzzs. The second night — a poor sleep night for me — the Sense thought I slept for just two hours.I think I got more, but I was pretty tired.

When it works, you get an overall sleep score — a number closer to 100 is better — as well as a look at your heart rate and estimated oxygen variation. Fitbit’s app also shows the amount of time you spent in light, deep, and REM sleep. 

Fitbit Sense review: Fitbit Premium

If you subscribe to Fitbit Premium ($$9.99/month, or $79.99 per year), you get a few additional features, many of which are deeper dives into certain measurements.  

A Health Metrics dashboard will let you view your 7-day and 30-day history for heart rate variability, breathing rate, oxygen saturation (SpO2), and skin temperature variation. Given the importance of some of these features, Fitbit said it was looking at a way to bring more of them to non-Premium members.

Aside from that, Fitbit Premium subscribers get access to a number of video workouts they can watch on their mobile devices, which are as short as three minutes and as long as 30 minutes that cover all parts of your body. Examples include “10-minute Glutes with Katie,” “3-minute Leg Challenge,” and “15-Minute HIIT with Lisa.” There are even a couple of cooking videos.

There are also 16 guided programs, which include everything from encouraging better sleeping and eating habits to running and weight training. 

Fitbit Sense review: Smartwatch features

While not as robust a smartwatch as the Apple Watch 6 or the Samsung Galaxy Watch Active 3, the Sense covers the basics, plus a little more. 

If you’re looking for a smartwatch that will let you check your bank balances, control all your smart home devices and make phone calls untethered, this isn’t it. Fitbit’s smartwatch app store is nowhere near as large as Apple’s, but there are third-party apps for Starbucks, Uber, Yelp, Walgreens, United Airlines, Strava, The New York Times, and a few others. You won’t find MapMyRun on the Sense, as Fitbit probably prefers you use its run-tracking.

The Fitbit Sense can store playlists from Deezer and Spotify, so you can play music right from the watch. While you can control Spotify from the watch, you can’t download music from that service to the watch itself. Considering Spotify is one of the largest music services, I hope this changes soon. 

Like the Versa 2 and Versa 3, the Fitbit Sense has Alexa built in, so you can summon Amazon’s voice assistant from your wrist. And, because Fitbit was acquired by Google, Google Assistant is also available. However, you can only have one assistant active at a time. If you're using Alexa, it will respond to you via the Sense's built-in speaker

You can also answer calls via the Sense when your phone is nearby and, if the Sense is connected to an Android phone, you can also respond to text messages via voice-to-text. 

And, the Sense has Fitbit Pay, which can be used at pretty much the same places as Apple Pay. 

Fitbit Sense review: Battery life

Compared to the Apple Watch Series 6 and Samsung Galaxy Watch, the Fitbit Sense’s claimed 6-day battery life is absolutely epic. (If you’re using GPS actively, the battery life is about 12 hours). Considering the watch is meant to be worn all day and night, it helps that you don’t have to remember to charge it every day. 

After four days of wearing the watch day and night, plus one 30-minute run using GPS, my Sense watch was down to 19 percent, which is excellent and roughly in line with Fitbit’s claims. A half-hour run using GPS knocked the battery down by four percent.

The Sense comes with a proprietary magnetic USB charger, which snaps securely to the back of the watch; mine went from 19 percent to fully charged in less than an hour.

Fitbit Sense review: Verdict

I get a lot of pitches for gadgets claiming to offer better sleep, health, and fitness, and many of them feel like high-tech snake oil. For every ailment, there seems to be a tech-based solution. And, even with the more reputable companies, some features blur the line between a government-approved medical device and one that’s not.

That’s why I like the Fitbit Sense’s approach to things such as its SpO2 and skin temperature sensors. By not allowing you to actively check your blood oxygen levels, it makes it less likely that someone will use the Sense rather than an FDA-certified device to make sure you’re healthy. Rather, it uses these readings, as well as a handful of others, to give you a more rounded view of your body. While the Apple Watch 6 is still the best overall smartwatch, the Fitbit Sense offers the most of any smartwatch when it comes to your health.