- ECG and top health features
- Improved design with a button
- A week of battery life
- Stress tracking didn't impress
- Poor OS and no apps
We loved the original Fitbit Sense back in 2020, which arrived mid-pandemic with a focus on health tracking that truly resonated with us.
Since then, things have changed. The company has taken a new approach to continuous Afib detection, which is now available on every Fitbit.
It's the same for the Health Metrics dashboard, which arrived with the original Sense smartwatch, but even the budget Fitbit Inspire 3 can now offer a full range of tracking, even body temperature.
This has diluted the Fitbit Sense 2, and leaves question marks about its $299/£269 price tag, especially against the Fitbit Versa 4.
Read on for our in-depth testing and conclusions. And make sure you read our guide to the best Fitbit for your needs.
Features and ECG
The Sense 2 still shares its design language with the Fitbit Versa, but both new-gen devices have been given a lighter case design and a physical button while retaining the same bright AMOLED display. So, what are the main differences?
Firstly, ECG. The Fitbit Sense can take spot-checks on heart rhythm using the built-in sensor.
However, the Versa 4, like the rest of the Fitbit range, will scan for irregular heartbeat events using the PPG sensor. It means that all Fitbit devices can warn you about a potential AFib event – so only those who have a heart condition will benefit from the ability to spot check via the ECG sensor.
The Sense 2 also uses a continuous electro-dermal sensor (cEDA). The EDA sensor on the original Fitbit Sense could spot-check for skin responses to stress, while the Sense 2 can do that automatically.
Continuous ECG is the basis of the overhauled Stress Management feature, which is now the key focus of the Sense 2.
Stress tracking and integration
Stress Management is the headline feature of the Fitbit Sense 2 – and it’s been overhauled, with that cEDA sensor now constantly scanning for stress responses.
If it detects a stress response, you’ll be prompted to log how you were feeling from a range of pre-set emotions. We expected this to be annoying, but we were rarely prompted more than once per day.
The language is a little vague, though. A big alert saying "CHILL OUT" might be what you expect. However, the actual alert on the wrist just mentions "changes" in your body.
It’s not even clear whether the Sense 2 thinks these are good or bad changes, which kind of undermines what comes next.
At this point, you can input your mood using pre-set icons, and, over time, you can view triggers and see how they correspond to moods. But you can’t tag triggers to real events.
It’s a prompt ultimately, then, that makes you aware (in its own opaque way) that your physical state has been diminished, but is that enough? It's about identifying triggers, and just being aware of when you're feeling stressed. If you struggle with stress, this could be useful for you.
From this screen, you can start a breathing and mindfulness session, or an EDA Scan session on the watch.
The guided breathing is more active than we’ve seen on other wearables, and encourages you to match your breathing to patterns shown on the watch face, and it uses nifty color-coded feedback in real-time to show when you're breathing is in sync.
It's surprisingly effective, and a smart use of the sensors.
The EDA Scan is a two-minute time out, where you place your palm over the screen.
In turn, EDA Sensor counts how many stress responses were registered – a number that struggles to be meaningful in our eyes. However, the app now shows your current heart rate variability compared to your baseline, which does make it a more interesting and useful process.
We know from move reminders (also present on the original Sense) that when they arrive during work meetings, dinner with friends, or while getting on with life’s other demands, it’s not always convenient to get up and do 200 steps because your wearable said so. The same could be said of these reminders.
It means that anyone considering Sense 2 should have stress and wellbeing as a specific goal. We think that's quite a niche consideration for those sizing up a wearable, and we were left a little cold by it all.
Health watch, not a smartwatch
We'll start with the good stuff.
The Health Metrics dashboard is still a great overview of your health, too, tracking oxygen, heart rate and skin temperature against established baselines.
And the (Premium) Daily Readiness score is a great addition. However, all of these features can be found even on the budget Fitbit Inspire 3.
It calls into question why you should pay more for the Sense 2, and it increasingly compares unfavorably with other premium smartwatches.
Still, notifications are delivered well and are easy to read, and control of the apps that can deliver to the wrist are controllable, so you can stop yourself from being inundated. And you can also take calls from the wrist.
Fitbit Pay is on board, too, and there's Google Pay if you run an Android device.
We also really enjoyed the smart alarms, which are great for early starts. There’s a decent weather widget, and Alexa can be summoned using the physical button if you like that kind of thing.
But there are shortcomings of the Sense 2 as a smartwatch, which makes the launch of the Pixel Watch a timely intervention for Fitbit.
There’s zero support for Fitbit OS from an app selection standpoint. That means there’s very little that can be added to the smartwatch in terms of features.
We also found the watch face selection to be both poor and ridiculously clunky to implement. Changing the watch face is akin to putting the watch through a huge voluntary update. And many of the faces in the gallery are paid-for options.
We also found some of the navigational elements of the Fitbit OS are a little annoying to use. Menus are a tad sluggish, and we found some miss-presses can easily send you back to the watch screen or accidentally pause workouts.
Likewise, the always-on display worked well, but we found the wrist raise to wake the screen into full power mode was a little fiddly and sometimes didn’t register.
There are plenty of compromises here, but it’s a passable smartwatch performance overall. And the pay-off is incredible battery life, which eclipses the Apple Watch Series 8 and Pixel Watch.
One of the key selling points of the Fitbit Sense 2 is its battery life, and, as standard, you can expect around a week between charges.
That was borne out in our testing, and we easily achieved the six days quoted by Fitbit. This is pretty much on par with the Fitbit Versa 4, so, again, there’s little to choose between the two devices.
However, if you do choose the always-on display – this will be decimated to around three days.
We have slightly criticized the always-on display and the wrist-raise function – and, with the battery life impact, we’re not sure we fully endorse it.
A good workout partner
We found the Fitbit Sense 2 has been a decent partner for workouts, with runs and yoga tracked well.
While out on runs, there’s not a huge amount of data – but it’s easy to read on the bright AMOLED display, and those fields are customizable.
We got a GPS lock quickly and runs came up generally accurate – although a short 7km run came up 200m short of the Apple Watch Ultra.
On closer inspection, it was obvious that the Sense 2 suffered from significant wandering of the GPS signal throughout the run (in a largely residential area). That’s compared to the Apple Watch Ultra’s multiband GPS, too, which has aced accuracy tests.
Analysis of runs is fairly comprehensive, with split times, heart rate zones and elevation all tracked, and you can link Fitbit to services such as Strava for detailed evaluation.
You can also see VO2 Max estimates within the heart rate dashboard area, which is called Cardio Fitness Score. As it has been for many years, Fitbit’s estimate is significantly higher than Garmin’s – which we validated as the most accurate via a lab test.
It follows on from questionable accuracy on the Fitbit Charge 5 and indicates that the Sense 2 isn’t geared towards the best levels of running accuracy. It should be fine for most runners, but not those that crave the best feedback.
However, again, all of these features are available on the cheaper Versa 4.
How we test