Polar Unite review

We tested the Polar Unite for more than a week, wearing it continuously so that we could track general activity, sleep and exercise.

We tried a variety of different workouts during this period, including strength training, walking, HIIT (high-intensity interval training) and some of the guided workouts that are suggested by the fitness tracker itself, including cardio and stretching routines. 

Alongside the Polar Unite, we also wore the Fitbit Charge 5 and Garmin Vivosmart 5, so that we could compare the devices in terms of accuracy and consistency.

We looked to compare heart rate tracking, step counts, calorie burn estimates, as well as see how they compared in terms of features and battery life. 

Finally, we made use of the Polar Flow app to see how well the data syncs, how easy the app is to use, how well it presented the data and whether it explained what the information meant, or provided any other support. 

Opening the box, you have the usual paperwork, including a quick start guide. There are two watch straps, one shorter than the other, so you can choose the one that most comfortably fits your wrist.

There’s also the fitness tracker itself, and a charger. You need to plug this in and charge the device to wake it for the first time so you can set it up. You can either set up via your phone, or on your computer. We chose to use our phone. 

Setting up the Polar Unite was straightforward and follows a similar pattern to most other devices we’ve tested. Download and install the Polar Flow app (iPhone|Android), and create an account (if you don’t have one already).

Once you’ve done this, switch on the fitness tracker, and wait for the app to detect it. The rest of the setup process involves going through a series of screens and is simple. 

The single biggest issue was the software update that was needed, which took around 20 minutes. But otherwise, there was nothing complicated about the process.

The Polar Unite stands out from a lot of the other affordable fitness trackers we’ve tested, primarily because it looks more like a traditional watch than the ‘band’ shape, which is commonplace.

It takes a lot of design cues from the slightly more expensive Polar Ignite, in that it has a round face, one button, and a touchscreen. It looks very smart, and the round face is a lot larger than many other fitness trackers. The body feels well-made and robust. 

The screen is bright and colourful, but not quite as sharp as the AMOLED screens we’ve seen on devices like the Charge 5 and Inspire 3 from Fitbit. It isn’t unattractive, but side by side there is a clear difference in how they look.

We were initially reminded a little of the slightly blocky quality of Ceefax and Teletext. It’s still clear though, and visible even in bright sunshine. 

The biggest issue we had was with the textured silicone wristband. The fastening mechanism is a plastic pin that you push through the relevant hole.

It takes some getting used to and can be quite fiddly. We found it tended to pinch our skin and give us an unintended waxing. It is, by far, the most uncomfortable strap we’ve put on. Once on though, it was comfortable. And if you don’t like the strap that comes with the fitness tracker, it’s easy to replace it with the quick release mechanism. Plenty of wristband options are available online. 

We’ll start by saying that compared to a lot of fitness trackers, the Polar Unite is relatively light on features. It lacks, for instance, things like music controls, contactless payments and stress monitoring. These are features that are available on some, if not all, of its competitors.

It does offer basic notifications such as call, app and text alerts, but it isn’t a smartwatch – you won’t be able to take a call, for example. 

Despite this, the Polar Unite still offers what we’d describe as the essentials – heart rate, sleep and step count monitoring, estimated calorie burn, and activity tracking. And these features are done with a lot of thought.

Perhaps its most interesting feature that you won’t see on lots of rival products is recommended activities, which we’ll explain in more detail in a moment.  

As we mentioned above, health and fitness tracking is narrowly focused on exercise tracking, heart rate and sleep monitoring, and little else. But arguably, rather than breadth, Polar has decided to go for depth, and really drill down into what it’s recording. 

You’ll see a daily activity goal bar which fills up as you move around during the day. It also counts how many steps you do each day, the total distance you cover, the amount of ‘active time’, calories burned, and you also get the slightly more negative ‘inactivity stamp’ if you stay sat down for more than an hour without moving around. The tracker will buzz to prompt you to move before that happens, though. 

The Polar Unite also tracks heart rate throughout the day, although you do have the option of turning this off (which will boost battery life). You’ll get summary data to tell you your highest and lowest heart rates of the day as well. 

Exercise tracking is comprehensive and covers an enormous range of different activities, which can be selected via the Polar Flow app. This includes common exercises such as running and cycling, to more niche pursuits, such as Nordic walking, Snocross, and many more.

It’s an impressively comprehensive list, although you can only have a maximum of 20 shortcuts on the watch at a time. 

Starting a workout is also simple. Press the button on the fitness tracker to bring up the ‘start training’ option, select it by tapping on the screen, choose your workout by scrolling and then tapping the relevant choice, and off you go. Press the button again to pause the workout, and then press and hold it to finish.  

One other interesting feature is the fitness test. While many fitness trackers will offer an estimate of your VO2 max (an indication of your cardiovascular fitness) after you’ve exercised, the Polar Unite does this by getting you to lie down and relax for three minutes, and then tracking your heart rate.

It’s a feature that we can imagine being quite motivational if people start seeing their score improve over time. When testing this feature, we found that any small movements could cause it to fail, and we’d have to start again.

It also gave us a much lower VO2 max score than either the Fitbit Charge 5 or Garmin Vivosmart 5.  

Sleep tracking is another area that Polar has paid a lot of attention to. As well as tracking the basic duration of your sleep and the time spent in the different types of sleep (deep, REM and light) the Polar Unite will also give you a ‘sleep charge’ score.

This measures your sleep by factors such as duration, continuity, and how regenerative it was. 

This then feeds into a pair of features called ‘Boost from Sleep’ and ‘Nightly Recharge’. The first of these tells you out of ten, how your recent sleep is contributing to your readiness to perform on a given day.

You can also see it as ‘modest’, ‘fair’, ‘good’ or ‘excellent’. You need to wear your watch for three nights before you start getting a Nightly Recharge score. 

Nightly Recharge looks at your sleep and autonomic nervous system (which controls your fight or flight response) to see how your body is recovering from training and stress from the previous day.

It’s based on your heart rate, heart rate variability, and your breathing rate while you sleep. You’ll get descriptions such as ‘poor’, ‘compromised’, ‘OK’ and ‘very good’. 

The idea is that this can then help you decide whether to push hard, or take things a little easier, and will offer a brief comment to let you know whether it thinks you should go for it, or back off.

It’s like the Daily Readiness Score on Fitbit, or Garmin’s Body Battery. It works well, and we could envisage this being particularly helpful to people who are just getting started with exercise. 

One of the most interesting is features is the ability for the Polar Unite to recommend certain activities for you. It does this by monitoring what you’ve done previously and will then make what it feels is a suitable suggestion.

You can access this by pressing the cog symbol next to any of your workout shortcuts, and then selecting ‘Training Suggestions’.

You may then see a strength workout recommendation, a cardio suggestion, or something labelled as ‘supportive’, such as dynamic stretching. 

After a few days of being active, the watch suggested we do some light cardio or stretching. When you select one of these, you’ll get a breakdown of the moves.

After you start your chosen activity, the watch will cue you for what you need to do next and will set a timer (where appropriate). It will buzz vigorously when it’s time to move on. 

It’s a nice feature, and again, one that we can imagine being useful for people who are just starting on their exercise journey.

Knowing when to rest and recover is every bit as important as pushing hard, and the combination of strength, cardio and stretching appears to be a fairly complete approach to improving someone’s fitness.  

The Polar Flow app is a relatively simple store for your data. It isn’t the most intuitive, but once we got used to it, we liked how it presents your information. Where many devices sync with the app automatically when you open it, with the Polar Unite, you must hold down the button on the fitness tracker until it starts syncing.  

As we mentioned above, it tracks and records all your data each day, and presents it all in a minimalist fashion. If you want to drill down into any of the data, tap on the specific metric, and it will load a screen with lots of graphs and supporting information.  

It’s a sensible way to avoid overloading someone with data, but still allowing them to get that extra insight if they want it. There isn’t a vast amount of extra content, and if we compare it to the likes of Fitbit, which offers recipes, workouts and guided meditations, it may appear to be lacking (although unlike Fitbit, Polar doesn’t charge extra for any of its content). But it’s a very user-friendly app, thoughtfully put together. 

In general, we felt that the Polar Unite performed well, although there were some notable differences between what it recorded in comparison to the devices we were testing alongside it.  

With step counting, the Polar Unite was generally a couple of thousand steps higher than either the Fitbit Charge 5 or the Garmin Vivosmart 5. The largest difference was around 5,000 steps (21,600 vs 16,278), while the smallest was about 700 (14,151 vs 14,867).

This is quite a wide margin of variability, and it’s difficult to know exactly why this was the case. It’s equally impossible to know whether the higher or lower number was more accurate. 

In terms of calorie estimates, there was much greater agreement across all devices. There were still differences, but generally between 100 and 300 calories, which suggests a strong degree of consistency among the devices. On one occasion there was as little as a three-calorie difference between the Polar Unite and the Vivosmart 5.  

There were a few occasions when we felt the touchscreen was a little unresponsive. We’d try to swipe the screen and it would register as a press, or vice versa. And similarly with the button, particularly during exercise, we would press it to wake the screen to see our stats, only to accidentally pause the workout.

These are relatively minor irritations, but it was far more often an issue than with some other budget fitness trackers we’ve tested, such as the Charge 5. 

We felt that activity tracking was very good, and never noticed any issues with connection being lost, or weird heart rate spikes appearing in our workouts.  

Calorie burn estimates after any of our workouts tended to be much lower with the Polar Unite than with the other fitness trackers we tested. On some occasions, the Polar Unite estimated only half the calorie burn of the other trackers (which could be as much as 200 calories).  

This is potentially significant, because if someone is trying to run a calorie deficit to improve their body composition, for example, then the wrong number could mean they are potentially eating more than they need or want to. Or, not enough, if they have burnt more calories than they think they have. 

Once again, it’s almost impossible to know which device is right. But it’s potentially noteworthy that the Charge 5 and Vivosmart 5 were much more closely in agreement with one another in calorie burn estimates during exercise. And it’s interesting that despite the fairly large differences in calorie burn estimates during exercise, the overall daily estimates remained closely aligned. 

GPS performance wasn’t great. The Polar Unite relies on connected GPS, which means it uses your phone to measure distance, rather than its own GPS signal.

On our usual 5.6km route, it was consistently close to a kilometre below the distance tracked by the Charge 5 (with in-built GPS) and, interestingly, the Vivosmart 5 (which also uses connected GPS). This is another significant variation, which might account for some (though not all) of the calorie burn estimate differences as well.  

Heart rate tracking was much more consistent between devices, and the Vivosmart 5 and the Polar Unite were particularly closely aligned. Maximum heart rates were usually no more than three or four beats different, while average heart rates were usually no more than five to ten beats per minute different. 

This suggests a good level of accuracy, something we’d expect given Polar’s expertise in heart-rate monitoring. 

We routinely highlight the fact that sleep tracking is notoriously difficult to measure, and we routinely see big differences between different devices.  

On this occasion, there were similar variations between devices. While overall sleep duration was broadly in the same ballpark, there were big differences between measurements for light, deep, and REM sleep periods. The app at least presents the data in several ways, so it’s easy to understand what the fitness tracker recorded. 

We’d suggest that sleep tracking should be used for general guidance, rather than being taken as definitive. And in the case of the Polar Unite, it’s metrics such as nightly recharge, which is drawing data from your heart rate and breathing, that will be more useful to most users.

Polar says that the Unite battery will last for ‘up to’ four days. In our experience, we never made it this far. The best we managed was typically around three days. While some smartwatches, such as the Apple Watch, often need charging daily, three days is still on the low side for a fitness tracker. Especially when some alternatives like the Fitbit Inspire 3 offer closer to ten days or more.  

We noted that on days where we tracked a 30-minute workout and a one-hour walk, the battery tended to drop by around 30%. But interestingly, we completed one tracked walk for an hour and found the battery had only declined by 2%. When we tried the fitness test, the battery seemed to drop by around 6%, even though that only took three minutes. 

It was, however, quick to charge. On one occasion, we went from 8% charge to 100% in an hour. And in ten minutes, battery increased by 22%. This might be enough to get you through another day or so before you need to charge it again.  

We do need to mention the very unusual charger. It’s a plastic USB device that clips onto the back of the Unite, then plugs straight into a suitable plug. The positive is that it holds the device tightly, so there’s no risk of it losing connection and not charging.

The drawback is that depending on your plug type, and where your sockets are on your wall, it may be more difficult to plug in than a cable would be. 

At full price, the Polar Unite does feel quite expensive, especially when compared to rival products. For example, the Fitbit Charge 5 is often available for under £100 and offers more metrics than the Polar fitness tracker. It’s certainly toward the top end of the ‘budget’ fitness tracker category. 

However, having been around since 2020, it does mean that this device is often available for considerably less. We’ve seen it available for under £80, which puts it more in-line with the likes of the Fitbit Inspire 3. And at this price point, it starts to look like reasonable, though not spectacular, value.  

A lot depends on exactly what you want from your fitness tracker. If you want as many metrics recorded and measured as possible, this probably won’t represent good value to you.

But, if you want a device that focuses very heavily on exercise tracking and sleep, and ignores certain other metrics, then you’ll certainly find a suitable product in the Polar Unite. 

If you aren’t convinced that the Polar Unite is the right fitness tracker for you, then here are some alternative options to consider: 

We like the Fitbit Charge 5, especially now that the price has dropped considerably. You’ll generally be able to get this for under £130, and often below £100 when it’s on promotion. And for that, you get one of the few devices in this price bracket that has its own built-in GPS, which makes it extremely accurate for tracking outdoor exercise (if that’s your thing). 

It has a bright and colourful AMOLED screen that is easy to read, and it offers loads of health and fitness tracking metrics. It also benefits from the excellent Fitbit app. Unfortunately, a lot of features are only available if you pay for Fitbit Premium, which is £7.99 a month, or £80 for a year.

The Garmin Vivosmart is another device at the top of the end of what we’d consider ‘budget’. But it is an excellent all-round health and fitness tracker. It’s comfortable and lightweight to wear, and we felt it tracks activity very accurately, even without built-in GPS. It also utilises the Garmin Connect app, which we really like for how clearly it presents all your data. 

The screen is small and isn’t in colour, which is a slight disappointment. But one benefit of this is that it extends battery life to around a week. This is a potentially strong choice if you are getting more serious about your exercise routine.  

At the cheaper end of the fitness tracker spectrum is the Honor Band 7. With an RRP of £49.99, it significantly undercuts the Polar Unite and the other trackers we’ve highlighted here. But it still offers plenty of features, including blood oxygen, heart rate and workout tracking, music playback controls, and a large AMOLED screen that is bright and easy to read. Battery life is also up to 14 days, which is significantly longer than many fitness trackers. 

It may not have as big a reputation as Polar, Fitbit or Garmin, for example, but if you want to explore fitness trackers without spending a lot, this could be a contender. 

The Polar Unite is a good effort by Polar to offer an affordable fitness tracker that’s accessible to beginners. It offers most, if not all, of the fitness tracking metrics we would expect. And while we have some concerns about the accuracy of some of those measurements (particularly step counting), heart rate and calorie estimates appeared to be relatively in agreement with other devices. 

We liked the look of this fitness tracker, although the strap was not comfortable to put on. It’s quite unusual to see a budget fitness tracker that looks more like a traditional watch. And the screen, while not the best, is still perfectly usable.  

Where this device excels is the support it gives to beginners. As well as a simple app that supplies lots of data insights, the support on offer via the suggested workouts could be invaluable to someone who isn’t sure what they should be doing.  

For anyone who is looking for an affordable fitness tracker that focuses on the ‘essential’ metrics, the Polar Unite may be exactly what you’re looking for. It’s a solid all-rounder that offers plenty of guidance if you’re just getting started.  

• You want guidance and support on workouts 
• You prefer a fitness tracker that looks more like a smartwatch 
• Accurate heart rate tracking is important 

• You’re looking for accurate outdoor sports tracking 
• You want a wider variety of health metrics  
• You’re looking for more features such as contactless payments