Skip to main content

Fitbit Sense review: enough bugs to raise your heart rate

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

If you buy something from a Verge link, Vox Media may earn a commission. See our ethics statement.

Fitbit Sense on a gold tray
Fitbit Sense smartwatch.

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.

The Sense does what every Fitbit ever has done: counts your steps.
The Sense does what every Fitbit ever has done: counts your steps.

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.

Close-up of inductive button on the Fitbit Sense
Fitbit is using a capacitive button the side of the Sense, which proves harder to use than a normal button.
The various sensors used to measure heart rate and other metrics are on the bottom of the Sense.
The various sensors used to measure heart rate and other metrics are on the bottom of the Sense.

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.

Fitbit Sense screen with SpO2 clock face
The Sense can measure your blood oxygen levels, but only when you use this special watchface.

The other big, new metrics you get with the Sense are Oxygen Saturation (SpO2) and Skin Temperature. Both of these readings are taken as you sleep. You may only be newly familiar with Oxygen Saturation because much has been made about it (and with very good reason) due to the COVID-19 pandemic, where a drop in your pulse ox could signify a serious problem. The weird thing is that, currently, your Oxygen Saturation is only recorded if you select the SpO2 watchface. 

That watchface is fine, but it isn’t my favorite, which meant that I had to remember to switch my watchface to SpO2 every night before I fell asleep or I wouldn’t get a reading, which I didn’t always remember to do. This seems unnecessary, especially since you have to go into the app on your phone to dig into that data anyway. As for skin temp, it takes three days to establish an average, and from then on, it will tell you whether you were hotter or colder than normal. That can alter you to an oncoming illness or menstrual cycle or pregnancy, which would be useful, but it can also be impacted by significant changes to the ambient temperature or your bedding, which may make it somewhat less useful.

So what do we actually do with all of this data? For me, that’s always the missing part of the equation. I now have a ton of numbers in front of me, which I may or may not fully understand. But even if I do understand them, I’m not really getting any info on what actions I can take to improve things. How do I integrate this stuff into my daily life to actually be healthier? 

That’s where Fitbit’s new Stress Management Score, which combines your heart responsiveness (via heart rate, heart rate variability, and EDA scans), the impact of your physical activity, and how well you’ve been sleeping comes in. It includes a breakdown of what each item means and how you might be able to improve it using other features within the app (e.g., meditation, yoga, or exercise routines). The score itself is available for free to all Sense owners, but those that subscribe to Fitbit’s $9.99-per-month premium plan (the Sense comes with a six-month trial), will also get deeper insights into what the score means and how it’s calculated. Fitbit says it will be making the scores and reports that are in the premium-only Health Metrics Dashboard available to all Fitbit owners in the “coming months.”

The heart rate monitor on the Fitbit Sense.
The heart rate monitor on the Fitbit Sense.

While this isn’t the be-all and end-all, this is actually the closest I’ve seen any fitness tracker come to bringing everything together, both from a pure data perspective and a “what you can do about it” perspective. Fitbit’s Premium plan not only offers you a clearer picture of your overall health in the exclusive Health Metrics Dashboard, but it includes hundreds of meditations and video workouts you can try.

For those willing to pay more, Fitbit is launching a new personal coaching service that pairs you with a certified health professional. With this, you will be able to text with your coach every day (Monday through Friday). They will have access to all of your Fitbit data and work with you to come up with training and / or nutrition plans to help you meet your goals. Unfortunately, because of my tight review window, I haven’t been able to go too deep into this. But in the one day that I’ve been working with my coach, she has asked me a lot of good questions, and she seemed to understand my goals, metrics, and constraints. I’m cautiously optimistic about it. It’s $55 a month, which isn’t cheap, but that includes Fitbit Premium, and you’re likely to end up paying more for a single personal training session at a gym.

Confusingly, Fitbit also makes a Fitbit Coach app, which has nothing to do with the above mentioned personal coach. It’s a part of Premium, and it’s really just a repository of workout videos. But here’s the weird thing: it doesn’t actually integrate with your Fitbit. It tells you what the estimated calories are for a given workout before you do it, and then it just adds that number to the part of the app that logs your data. Why it doesn’t pull data from its own fitness tracker that you are presumably wearing to not only give you a better assessment, but also provide better recommendations for workouts that are right for you, is somewhat baffling. 

As with Fitbit’s Versa, the Sense isn’t just a fitness tracker; it’s also a smartwatch. I was testing it with my Google Pixel 3 XL, and Fitbit was able to key into the messaging APIs, so not only could I view incoming messages, but I could respond with quick texts and even voice-to-text. (These features are sadly not available if you pair the Sense with an iPhone.) I also liked that it was easy to control which apps on my phone can and can’t send notifications to my Fitbit. 

The Sense has NFC, so I was able to use it for mobile payments via Fitbit Pay, and it worked without issue. I can use it to control music on Spotify, but if you want to actually store music on your watch so you can leave your phone at home, you’re limited to premium services from Pandora and Deezer. I don’t think I know a single person who subscribes to Pandora or Deezer. 

There is a decent number of apps not just from Fitbit but from various third parties (as well as a gajillion watchfaces), which vary in quality. The Sense’s UI is newly redesigned, and I found it surprisingly intuitive to navigate, though some of the lagginess detracted from what would otherwise feel like a premium smartwatch experience.

There are a lot of watchfaces available for the Sense, of varying quality.
There are a lot of watchfaces available for the Sense, of varying quality.

There are also some features that are coming within the next few months that weren’t yet available for me to test. One is the ECG app, which is expected to arrive in October. You’ll open the ECG app on the Sense, put your thumb and forefinger on opposite corners of the device, and it will scan for signs of atrial fibrillation (A-fib). While the Sense already has Alexa built in, sometime soon, you’ll have the option to change that to Google Assistant, which I generally find to be much more useful on a device like this. Also, the Sense has a built-in speaker, so soon, you’ll be able to actually hear the audible replies from Alexa or Google Assistant, and you’ll be able to make phone calls from the watch itself, as long as your phone is nearby.

Overall, the Sense is a nice smartwatch, and it does indeed feel like it comes closer than anything I’ve used at getting the most complete picture of your day-to-day health. At the same time, there is a good amount of bugginess that still needs to be ironed out, which doesn’t jibe well with the Sense’s $330 price tag.

It also presents a bit of a conundrum for someone like me. I gravitate toward more rough-and-tumble activities, and Fitbit can’t touch Garmin’s pedigree (or battery life) in that arena. But when I’m not off on adventures, do I want a more holistic view of my health, especially as I start to age and soften in places I don’t want to soften? Yeah, I do. Ultimately, I think this watch has a lot of potential, but I’d give it a couple of months to see if Fitbit can work out the kinks.

Update, 2:40PM ET, September 22nd, 2020: Fitbit reached out to clarify that the Stress Management Score is available for free to all Sense owners, but those that subscribe to the Premium plan will receive more insights on what the score means and how it is calculated. We have updated the review to account for this information.

Photography by Brent Rose for The Verge