Fitbit Sense Hands-On: Better Health Tracking Than the Apple Watch

Health tracking and stress management are front and center

Images: Thomas Smith

I’ve worn a Fitbit nearly every day for the past decade — from the company’s original paperclip-like tracker launched in 2009 to its recent Versa smartwatch. That’s why I was excited this week to receive the Sense, Fitbit’s newest wearable and its most advanced smartwatch to date. Retailing for $329.95 and packed with more sensor technology than any other watch on the market, the Sense officially begins to ship on September 25. My Sense arrived three days early through a premium access program, making me one of the first consumers in the world to try out the watch. I’ll be testing the Sense in detail here on OneZero and doing deep dives into its stress monitoring, sleep tracking, exercise, and connectivity features. (OneZero paid for the watch so I could review it here; Fitbit did not provide a free review device or compensate me in any way.)

With the Sense, Fitbit has doubled down on what it does best: track your health. Yes, the Sense includes the option to install some apps from partners like Spotify and Starbucks. But apps have never been Fitbit’s strong suit. I’ve worn a Fitbit Versa for more than a year, and I’ve used the third-party apps only a handful of times.

Tracking steps, heart rate, sleep, and other health metrics is Fitbit’s core appeal, and I think the company does it better than anyone else. The Sense pivots hard to that core, with marketing that explicitly calls the Sense an “advanced health watch” — and it boasts the FDA clearances to back that up. This is a great move for Fitbit overall, especially since its pending acquisition by Google would likely give it access to Android and the Play store and thus far better apps down the road.

True to its name, the Sense is literally studded with sensors. It has the standard offerings of any health-oriented smartwatch, including an accelerometer and gyroscope to track steps and movement. It also displays the glowing green LEDs of Fitbit’s proprietary PurePulse 2.0 continuous heart rate tracker. The Sense adds onboard GPS — an upgrade over the Versa, which required you to sync with a phone to use GPS tracking. With the Versa, you had to carry your phone with you if you wanted to map a run or hike, but with the Sense, you can use GPS directly on the watch.

Multiple sensors are visible on the back of the Sense.

The Sense adds several new sensors, one of the most interesting of which is an electrodermal activity (EDA) sensor built into the watch’s bevel. Sometimes also called a galvanic skin response sensor, it measures minute changes in skin conductance, which can correlate with your emotional state. Basically, it’s a stress sensor.

The Sense also includes a skin temperature sensor, likely embedded in the watch’s mirrored back, and an electrocardiogram (ECG) sensor, which measures heart rhythms and detects atrial fibrillation — and was approved by the FDA only about a week before the watch shipped. Like most recent-generation Fitbits, the Sense includes a pulse oximeter, which measures the level of oxygen in your blood — a potentially useful Covid-19 metric and one of the stats Fitbit plans to use to diagnose sleep apnea.

With all this on-board kit, the Sense is slightly thicker than the Versa. Otherwise, the two watches are nearly the same size. The Sense has a slightly smoother, Apple Watch–like bevel, and the division between the bevel and the screen is less obvious. Beyond that, the appearance and form factor are much like the Versa and Versa 2.

The Sense’s form factor and style are nearly identical to the Versa and Versa 2.

One welcome addition is a redesigned plastic band. Fitbit has always struggled with its watch bands, and in my experience, they’re almost always the first thing to break. Still, when I was setting up the Sense in the Fitbit app, I was shown a screen with instructions for replacing broken bands—not a great sign.

Fitbit has redesigned its band for the Sense.

Yet the new band seems like an improvement over the stock band on the Versa. A plastic stud snaps into a series of holes on one side of the band to adjust fit, and the loose end tucks into a slot on its opposite side, not unlike the standard silicone Apple Watch band. This eliminates the little sliding clasp that the Versa used — and that inevitably broke after a few month’s use. Fitbit includes both a small and large band with the Sense. The watch fits me well and looks reasonably stylish.

Fitbit has never met a charger design it didn’t like, and every new Fitbit smartwatch uses some new variant — hooks that span the whole watch, cradles the watch snaps into, magnetic attachments, and more. The Sense is no exception. It includes a magnetically attached charger that snaps onto four conductive points on the back of the watch. The charging process seems relatively straightforward at first glance — we’ll see how it holds up as those conductive points corrode, fill up with sand or other debris, and otherwise degrade over time. Fitbit claims that the Sense has a six-day battery life, but early reports indicate that this is halved if you enable certain features, like the watch’s always-on screen.

Setting up the Sense was surprisingly easy. Fitbit doesn’t have a great track record with connectivity — one of the most popular videos on my gadget-centered YouTube channel is called “Fitbit Won’t Sync.” With the Sense, Fitbit seems to have finally hit on the idea of forcing you to delete your old device before adding a new one, which often helps the issue.

Fitbit has never met a charger design it didn’t like, and every new Fitbit smartwatch uses some new variant.

The setup for my Sense went smoothly — after downloading some updates, the watch was ready to use. Its OLED screen looks brighter and clearer than the screen on the Versa. It comes with a nicely designed watch face, which includes key metrics like heart rate and sleep, as well as graphs showing how you’ve progressed toward your step goal throughout the day. It also includes a somewhat less nicely designed watch face that integrates blood oxygen level data from the previous night.

The Sense’s stock watch face provides helpful graphs and real-time heart rate data.

You interact with the Sense through a series of swipe and touch gestures, as well as a single button on the left side of the watch. Weirdly, this isn’t actually a button you can press, but a solid-state button that looks like a tiny groove. It detects when you place your finger over it, responding with a brief vibration. I love hardware buttons and their pleasant, real-life haptics, so this feels like a loss to me.

The Sense has a single, solid state button

The button also doesn’t work especially well — each press takes me back to the home screen, no matter how deep into a menu I’ve ventured. That makes navigating the watch’s UI a bit of a challenge. I found that I had to place my finger at the far left of the screen — almost all the way to the bezel — and aggressively swipe right to move backward in the watch’s menus.

Otherwise, the design is solid, and the interface itself surfaces quite a lot of data. Fitbit places the icon for taking EDA stress readings front and center, which feels like a good choice for 2020. The readings themselves, though, weren’t quite what I expected. I was hoping to put my finger on the watch and get a metric for my physical stress level, like Welltory and other similar services provide.

EDA readings are structured as guided meditations.

Instead, EDA readings are structured as meditations, in which the you cup the Sense’s bezel in their palm, sit still for two to 60 minutes, and are told to “calm your mind and just breath” (if you’ve selected Quick Scan) or follow prompts in the Fitbit app for longer, guided sessions. At the end of a session, the watch displays a graph of “EDA responses.” What these actually mean is not immediately clear. My EDA responses started at nine and ended at five. My heart rate actually increased from 75 to 84 beats per minute during my measurement session — probably because I found it very annoying that a watch was ordering me to “calm my mind and just breath.”

Other metrics are more helpful. The Today app, Fitbit’s home screen for biometric stats, displays steps taken, real-time and resting heart rate, calories burned, floors climbed, sleep, food intake (if you choose to manually track this), weight (synced from your Aria scale), and more.

The Sense’s Today app surfaces a lot of biometric data.

You can drill down into each metric to see a variety of charts, daily and weekly comparisons, and detailed minutiae like how long you spent in REM versus deep sleep. (Some features are only available with a Fitbit Premium subscription.)

The Exercise app is similarly full-featured, with options for basic exercises like walking, biking, and swimming, as well as more niche workouts like kickboxing, martial arts, and bootcamp.

The Sense tracks a wide range of exercise types.

The latter seem pretty ambitious for our current world. Conspicuously absent are potentially more relevant activities, like “carry in a really big order of Pure Life water from the front porch,” “attempt to deadlift your Aeron chair because Equinox is closed and Amazon ran out of barbells,” and other more pandemic-appropriate options.

Another welcome addition is a feature that summons either Alexa or Google Assistant with a long press on the side button. You can then speak into the watch and have your virtual assistant do your bidding. This feature was introduced with the Versa 2 and is surprisingly helpful.

Yes, I would like to add chocolate chips again, Alexa.

Because Alexa is integrated with many devices around my home — including my Nest thermostat — I can perform magic like changing my home’s temperature with a voice command from the Sense. I found it helpful to add essential items (like chocolate chips) to my shopping and to-do lists right from the watch, using my voice. The Sense also allows you to dictate responses to text messages and use other voice functions. Fitbit promises the company isn’t listening to everything you say using the microphone on your wrist.

The Sense syncs all its data to the Fitbit app on your phone via Bluetooth or the watch’s own Wi-Fi connection. The app — and Fitbit’s ability to mine your data for valuable insights — is where the company and its products are best designed and most capable. Fitbit has always been just okay at building hardware. But its algorithms and health analytics software, especially around complex functions like tracking sleep, are best in class.

With the Sense connected to my Fitbit profile, my Fitbit app continues to display the exercise analytics, heart rate data, sleep analysis, step/distance metrics, and weight/food tracking that I’ve been using for more than a year with my Versa smartwatch. As with the analysis features on the Sense itself, some of these are only for Premium users/subscribers.

Fitbit Premium app and data analysis.

Connecting my Sense, though, added a few more tabs to the app. The first is a “stress management” tab. As with the icons for EDA readings, Fitbit places stress management front and center in its user interface. The Sense’s packaging is also emblazoned with bold-type text reading “Stress Management Technology,” suggesting that the company is planning to make these new features a core selling point of its products.

Fitbit’s stress management functions appear to be more than just marketing hype. These functions in Fitbit’s app take a multifaceted approach to tracking stress, integrating common metrics like heart rate variability (HRV) and resting heart rate elevation, as well as EDA readings and heart rate readings taken during sleep.

The new stress management tab takes a holistic approach to tracking physical and emotional stress.

Fitbit combines these readings with data on sleep quality — including sleep debt, restlessness during sleep, proportion of REM sleep (which is linked to anxiety and depression), and sleep disruption, as well as overall activity levels and fitness fatigue. The company integrates your self-reported stress levels (on a one-to-five scale), which you can record in the app or on the watch during an EDA session.

Fitbit aggregates all this data into a daily stress management score, measured on a one-to-100 scale, showing how well you’re coping with emotional and physical stressors. You can track this score over time and experiment with life changes — like increasing sleep, starting a meditation practice, or exercising more frequently — to see how they affect your overall stress levels.

With all of the Sense’s health metrics, it’s important to note that Fitbit has designed its software less around providing an instantaneous snapshot of your current vital signs and more toward tracking broad health trends over time.

A stress score seems like the perfect metric for 2020 — and I love that Fitbit is taking into account a variety of factors to create a single, holistic metric that I can monitor and tweak. At minimum, the stress management score promises increased mindfulness, making you more aware of how stress may be affecting you mentally and physically. Combined with personalized recommendations that Fitbit already provides for sleep and exercise, the metric could provide an actionable way to increase your resilience and manage chronic stress amid world events that often feel impossibly overwhelming.

Another new tab in the Fitbit app is labeled “health metrics.” This provides raw data on a variety of medically oriented metrics, including nighttime breathing rate, HRV, blood oxygen levels, and resting heart rate. Over time, Fitbit will likely integrate ECG and other heart health data — as well as metrics like blood pressure and VO2 max — into this tab.

The health metrics tab provides drilldowns into medically oriented metrics.

Health metrics (and a separate “temperature” tab) also provide trend data on your skin temperature. Once Fitbit establishes your personal baseline value, a process that takes three nights, the Sense can warn you if you might have a fever. Combined with core temperature readings, which the Sense allows you to input from the Today app, these metrics could improve Fitbit’s existing tracking of menstrual cycles and fertile windows for biologically female wearers, as well as tracking Covid-19 infections.

With all of the Sense’s health metrics, it’s important to note that Fitbit has designed its software less around providing an instantaneous snapshot of your current vital signs and more toward tracking broad health trends over time. Fitbit’s app won’t easily answer the question like “What’s my current temperature?” or provide a numerical value for blood oxygen levels. Instead, it’s geared toward answering questions like “How is exercise affecting my heart’s health?” “How physically stressed am I this week?” “Am I coming down with something?” or even “Is that ‘something’ Covid-19?”

In other words, the Sense does not act as a replacement for vital signs taken by your doctor — or even measurements like body temperature that you might take routinely at home. Instead, as an always-on device that Fitbit would ideally like you to wear 24/7, the Sense is constantly gathering data on your health, analyzing that data using Fitbit’s algorithms, and providing a broad picture of overall trends in your health — as well as your daily actions’ impact on those trends.

That’s something you should also keep in mind when looking at the Sense as a piece of hardware. Is the watch as slick, stylish, or user-friendly as the Apple Watch? Definitely not. But reviews that harp on this are missing the point. The Sense is less a full-featured smartwatch and more a health data–gathering device wrapped into an acceptably capable wearable.

Criticizing Fitbit’s hardware on UI or style grounds is a bit like criticizing your heart surgeon’s practice for having a drab logo or boring magazines in their waiting room. Yes, those things are a bit annoying, but ultimately, they’re not why you’re there. No one is about to offer a $115,000 diamond-studded upgrade to the Fitbit Sense, as some have done for the Apple Watch. But if you want a device that’s laser-focused on improving your health—and with Covid-19 tracking and arrhythmia detection, possibly saving your life—then the Sense is almost certainly your best bet for a wearable.

Because many of the Sense’s functions require gathering data over the course of weeks or months, I’ll be continuing to test the device and reporting back about my experiences here at OneZero. Stay tuned for more detailed reviews, deep dives, and long-term impressions as I continue to put the Sense through its paces.

I can’t guarantee that I’ll follow the Sense’s edict to “calm my mind and just breathe.” But together, we’ll learn about whether the watch can really reduce my stress and improve my sleep — or at least ensure that I never run out of chocolate chips.

Co-Founder & CEO of Gado Images. I write, speak and consult about tech, privacy, AI and photography.

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