Fitbit Sense review: enough bugs to raise your heart rate

Fitbit’s latest smartwatch has sensors, and bugs, galore

When Fitbit announced the $329.95 Sense last month, it was being hyped as the company’s most-thorough health tracking device yet. With new features in the form of stress management (with electrodermal activity monitoring), skin temperature, oxygen saturation while you sleep, and an upcoming Food and Drug Administration-approved ECG-app, it seemed poised to give us the most holistic look at our health of any consumer-facing wearable yet.

Unfortunately, after testing the Sense for the past week, the impression I’ve gathered is that Fitbit tried to do too much in too little time, which results in a smartwatch that feels slightly unfinished.

Note: Because of the way Fitbit structured the embargo on reviews, I had far less time to test than would be ideal for this kind of device (just five days). Many of the features of this watch are designed to give you a longitudinal look at your overall health. To evaluate those features, you need to spend upwards of a month using the device. That being said, as this watch is becoming available this week, we felt it appropriate to give you a look at how this watch performs. We may update this review down the road if longer-duration testing proves to garner important insights.

Let’s start with the display. The Sense’s touchscreen is a 1.58-inch OLED (336 x 336 pixels) display. As you’d expect from OLED, it has dark, inky blacks and vivid colors. While the screen is fairly reflective, it’s bright enough that I’m able to read it even in direct sunlight. Even though OLED displays are energy efficient, enabling the Always On feature cuts battery life in half, from roughly six days to about three.

I opted to do it anyway because, for me, the whole point of wearing a smartwatch is being able to quickly steal a glance at stuff (the time, a notification, your pace on a run, etc.) without disrupting the flow of what you’re doing. Additionally, I found that half the time, the display didn’t light up when I wanted to, leading me to make increasingly exaggerated “I’m looking at my watch!” gestures. I’d rather take the hit on battery life.

I also found that the touchscreen isn’t nearly as responsive as I would like. I would frequently have to re-tap or swipe. The watch seems to get a bit overwhelmed, and there is stuttering in animations when making gestures. This just makes the whole experience less fluid than it ought to be.

The watch itself looks not unlike an Apple Watch, which isn’t a bad thing. There is a variety of bands to choose from (I tested it with a standard silicone strap as well as a soft leather band), which you can easily swap out in just a few seconds — a marked improvement over the Versa’s difficult-to-change straps — and the watch looks good with just about anything you might wear, from a tuxedo to ratty gym clothes.

The easiest way to tell the Sense from the Apple Watch is that instead of the dial the Apple Watch has on the right side, the Sense has a “solid-state button” on the left. It is, essentially a small, sunken area with capacitive sensing. When you press it with your finger, the watch vibrates, giving you the impression that you’ve pushed a button, even though nothing has physically moved. A single press takes you back to the home screen, a long press can be programmed to open your favorite app (by default it opens Amazon’s Alexa virtual assistant), and a double-press will open a shortcut to your four favorite apps.

I do not like this solid-state button. Unless you cover the entire button with your finger or thumb when pressing it, it won’t register, which leads to a lot of fiddling. Do you know what rarely suffers this kind of problem? A normal button. Another issue is that at certain angles the left side of the watch will just happen to press into the flesh of my forearm, which the Sense kept reading as a long-press, and so Alexa was constantly popping up and listening for a command. It happened so often that I eventually disabled long-pressing all together. Not ideal! The whole promise of smartwatches is increased convenience, so anything that’s even a little inconvenient is especially galling.

The Sense is equipped with GPS, which can be used for more accurate tracking of things like runs, hikes, and bike rides. I found the GPS to be as accurate as I needed, and it did a good job of tracking me even among the tall buildings of Manhattan (which is a nasty test for GPS watches). The Sense boasts improved heart rate tracking with its PurePulse 2.0 technology, which uses a new multi-path heart rate sensor. Basically, that means it’s checking your heart rate in more ways and in more places, which, when combined, should provide a more accurate picture of what your heart is doing.

This is something I would have liked to spend more time testing, but early results were promising. I would spike my heart rate doing some exercise and then would manually count my beats per minute using a stopwatch and compare it to the Sense. Not only did the Sense generally stay within a few BPM of my manual count, but it would usually get up to speed faster than the Garmin Fenix 6 Pro Solar, which seemed to have a bit more lag.

One of the banner features here is an electrodermal activity (EDA) sensor and on-watch scanning app. EDA is something that happens primarily in the sweat glands in your skin, and it’s a part of your body’s sympathetic nervous system. This is still actively being researched, but there is a lot of evidence to support the theory that when you are stressed out, your body is more likely to produce an EDA “event.” The way it works on the Sense is you start the EDA Scan app, and choose whether you want to do a two-minute Quick Scan or a Guided Session up to 60 minutes. In either case, you then sit quietly, attempt to relax, and cover the entire screen of the device with your opposite hand, making sure that the flesh of your palm is touching all four sides of the device.

Basically, what we’re looking at here is meditation with metrics. In the half-dozen meditations I did, I found that it typically showed I would have one or two EDA events early on, and then I’d be clear for the rest of my session, even though my heart rate would fluctuate up and down as much as 20 BPM. This makes some sense, as it typically takes me a few minutes to relax and settle into a meditation. Those sessions were mostly over the weekend. Then, on Monday morning, I did a 7-minute session and had a whopping 10 EDA events, and I was indeed feeling vastly more stressed-out. So it seems like it did a pretty fair job of gathering metrics on my stress levels while meditating. What one is supposed to do with these metrics, however, is not entirely clear. But let’s circle back to that in a minute.