The Fitbit Sense is a really good wellbeing tracker with some fitness smarts thrown in

It offers some reliable basic training metrics and impressively ambitious smartwatch functions.

  • Built-in Strava and GPS
  • Really clear display even on the move
  • Aims to be equal parts credible training device and high-end smartwatch
  • ECG measurements and built-in stress tracker.
  • Slightly awkward button functionality


‘Typically slick with appealing aesthetics, this is more of a wellbeing tracker with some fitness smarts thrown in.’

General comments

This is the successor to the Fitbit Ionic, which launched in late 2017 and was due to be Fitbit’s competitor to the Apple Watch. Instead of trying to take on the likes of Garmin, Polar and Coros with geekishly detailed training metrics, Fitbit has focused – we think sensibly – on more general wellbeing. Think sleep tracker; mood logger; menstrual health tracking; ECG measurement function, and a completely new feature called an EDA scan, which measures electrodermal activity to monitor stress levels, of which more below.

The basics

It’s both durable and sleek: the casing is graphite steel, the glass is Gorilla glass (extremely shatter-resistant) and the wristband made from silicone. The graphics are very bold and colourful and drew comment from people who saw us using the watch. The overall look and feel is substantially improved from the Ionic, which felt a little cheap.

Fitness features

If you want detailed training metrics this isn’t the device for you. For example, you can’t set up specific interval sessions with target reps or heart rate zones; instead you’re limited to ‘move’, ‘rest’ and ‘repeat’ which is better than nothing but sub-optimal given the effort expended elsewhere on the device.

The optical heart rate is similar what we’ve experienced on other devices, which is to say a very decent guide without being as reliable as a chest strap. It took a while to settle down after the start of a run – maybe five minutes – and there was also a bit of a lag between a change of pace and the heart rate reading changing to keep up with that. In terms of accuracy we found the readings to be 2-3 beats above a chest strap reading which is about standard.

GPS lock-on is quick and while we didn’t have access to a really built-up urban area we didn’t once lose signal on the 75k we clocked with the Sense.

The premium subscription gives you access to a bank of 20 training modes (yoga, HIIT, cycling and so on) as well as guided workouts, but you can’t transfer these to the watch so need to take your phone with you to take advantage of those.

Overall, as far as the training functions go, this will work perfectly fine for you if you’re simply after a lifestyle smartwatch with running basics such as time, pace, distance done reliably.

Smartwatch features

It gives you the usual call and message notifications, as you might expect, as well as Fitbit Pay and Alexa voice control. We also liked that you can dictate responses to messages on the device using the built-in microphone. It’s most handy when you’re driving but we quite enjoyed doing it as we walked down the street, holding our wrist either in Star Trek Beam-Me-Up or Secret Service Agent style, depending on our mood (yes, little things…).

The menstrual tracking function shows when female users are most likely to be fertile and allows them to log PMT symptoms to help build a picture each month.

There are also functions which measure blood oxygen saturation (SpO2) and skin temperature while you sleep. We’re unsure how mainstream such a function will become but we applaud Fitbit for trying to bring as much information as possible to the masses. SpO2 is especially relevant right now during the pandemic, since a drop in blood oxygen can be a warning sign of Covid infection (as was the case with President Donald Trump, who was subsequently hospitalised on the back of his SpO2 readings).

For the skin temperature reading you wear the Sense for three nights running and it gives you a baseline of your average temperature. Thereafter when you wear it at night it will chart any fluctuations. It’s not something most of us spend much time thinking about, but changes in skin temperature can mark the inset of infection of some sort, so if you’re a ‘knowledge is power’ person this will be grist to your wellness mill.

Stress sensors

The headline feature however is the EDA (electrodermal activity) scan. The Sense is the first smartwatch to offer this function, and tells you how much stress you’re experiencing. You hold your palm over the watch face and it uses electrical impulses to measure sweat gland activity. Used in conjunction with the app’s mindfulness meditation sessions and mood log you can build up a picture of how much stress you experience and when, as well as helping you to keep it under control. It’s easy to use and data geeks will love having further insight into what’s going on under the hood but it’s difficult to say how helpful most users will find this, as oppose to simply clocking their own sensations of sweaty palms, anxious feelings and so on. But functionality in this wellbeing niche is, we think, only going to grow exponentially to keep pace with the demands of society.

Other comments

Our main bugbear with the Fitbit sense was with the button function. The brand has reduced the number of buttons it uses on its devices to try and simplify things and on the Sense there is only…half of one? It’s a groove which sits on either side of the watch. It’s a capacitive sensor which means you don’t actually depress anything. You simply touch against the groove and it vibrates to show it has registered your touch. This sounds fancy (and it is) but it was very variable in its sensitivity to touch. Sometimes it registered immediately; other times you had to press quite hard more than once. We also found that when we cocked our wrist the pressing of the groove against our arm could inadvertently trigger some unwanted action.

Additionally many of the functions are only available with the Fitbit Premium app subscription, which is an additional £8/month. On top of an outlay of $499.95 for the device this is a bit of an irritation to say the least and may put some people off from investing. We think purchasers of Fitbit’s higher-end devices should get Premium access for free as standard. That said the Sense does come with an initial 6 months of Premium for free so that’s enough time to road test and see if you think it’s worth the extra.

RW verdict

As a product for the wider market we’re really impressed with the Sense – it’s got enough about it to make it a rival to the Apple Watch to all the but most devout Apple fans. From a runner’s perspective there’s not enough to make it a consideration for those to whom wide-ranging training functionality is key. But if you run as part of a more generalised health programme, are more concerned with staying healthy than breaking records, and/or love some clever bells and whistles with your gadgetry, the Fitbit Sense is well worth you taking the time to check out.

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