Polar A370 review

Fitbit Charge 2 and Garmin Vivosmart 3 rival delivers mixed results
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Polar A370
By Polar
Polar's A370 is a marked improvement on last year's tracker. The shift to more day-to-day wellness with the 24x7 HR will appeal to many, as will the sleep monitoring. The optical HR sensor is better, but still not perfect, but connected GPS definitely makes this more appealing as a fitness device. In sum, Polar's on more on a level with its tracker rivals, but there's still more to do.

  • 24/7 tracking
  • Added sleep smarts
  • Connected GPS
  • Iffy Bluetooth connectivity
  • HR accuracy still slips
  • Chunky (but not all that funky)

The fitness tracker has come a long way since the humble days of the Fitbit Flex, and the Polar A370 is the perfect example. Many of the features once only found in running watches are becoming more of a norm in more basic wearables.

Heart rate, rep counting, distance tracking; some even now include GPS. The Polar A370 doesn't have it all, but it's an impressively fleshed out tracker that builds on last year's A360, with new features and a few performance tweaks.

Read this: Everything to consider when buying a fitness tracker

Like Fitbit and Garmin, Polar is starting to think beyond fitness and towards health and wellness, and as such the A370 now does 24/7 heart rate tracking as well as sleep tracking, the latter using Polar's new 'Sleep Plus' technology. It's designed to be a tracker you keep on all day, all night - even in the shower - but is it justified by the performance? We've been testing it to find out.

Polar A370: Design

Polar A370 review

Removing the Polar A370 from the box and wrapping it around my wrist, I admit that I was a little put off by the look. It's hardly a rousing call to the fashion world to up their game, but it's not exactly hideous - maybe just don't opt for the orange band. In fact, to the naked eye it's identical to the A360, with a module that clicks into place. The thin loops keep the strap nicely in place, and I've found it perfectly comfortable to wear.

Certainly not as svelte as the Fitbit Alta HR, it's more similar to the Fitbit Charge 2. It's a little too on the chunky side, but not obstructive.

That screen is a different matter though; it's a vibrant, rich display that's easily readable unless the sun is really glaring down on it. Like the A360, you can change the watch faces by tapping and holding down on the display. I quite like the face with the bold numbers, which fill up with blue as you work towards your day's activity goal. Hit the top and you'll get some congratulatory fireworks. The display is always asleep until you either raise your wrist or tap the button on the bottom left side.

Polar A370 review

It does lose a few points for its micro USB port, which has a removable cap that I guarantee a lot of people will lose. I've already done that a few times. It seems like something that could have easily been avoided, and while the A370 is waterproof, I wouldn't recommend submerging it with the port exposed.

At 30m waterpoof, the Polar has another upper hand on its Fitbit rival, which is only "splashproof". Polar does say that if you're going to take it for a swim, the water will interfere with the heart rate tracking as is the case with most optical heart rate sensors. So you'd be better testing other metrics. More on that in a bit.

Polar A370: Features

Polar A370 review

Polar is following Garmin's footsteps, in that it started with more fitness-focused devices and is now venturing into the health and wellbeing domain, with the hardcore fitness bases still covered. It's about how fitness and sleep fit into the rest of your day, rather than separating your life into isolated chunks.

To do this, Polar brings all-day heart rate sampling to the A370, which the A360 didn't have. If you're not exercising, the tracker will take a sample every five minutes of the day - but will move up to once per second when you're in a workout. This is something you can choose to switch on or off, but having it on means you'll get some juicy graphs telling you when you had your highest and lowest heart rate through the day, and pinpoint your lowest heart rate reading during sleep.

I'll get into the meat of the heart rate tracking shortly, but for day-to-day measuring I tested it against different chest straps (Polar H10 and Wahoo Tickr X) and other wearables like the Charge 2 and Apple Watch, and found the numbers to be spot-on. So the data you're getting on these is reliable in that respect at least.

The A370 does quite a few things, but the interface is surprisingly bare; I quite like it. You can see an overview of your day on the display, which shows you your step progress for the day, details on any workouts you've done, and, again, your peak and lowest HR recordings.

Polar A370 review

As is custom with most trackers now, there's an option to check your current heart rate. Then there's an option to launch a workout, and Settings. And that's it. Polar's keeping things simple here, and I've found the experience better for it.

Boot up the workouts and you've got a menagerie of activities to pick from, from running to aerobics to strength training to hiking. Note that in all these cases it's just letting you customize heart rate zones and GPS differently; it won't start measuring things like reps or cycling cadence unless you pair a separate device. You can use custom-built Polar workouts though, which you'll need to do on Polar Flow and then sync to the tracker.

Here's something the A370 doesn't have: built-in GPS. But, like Fitbit, it has a connected GPS which uses your phone's signal. In practice, I found this less stable than I expected. I thought that if anything it would make for a stronger connection, even if it meant I had to take my phone with me. But I found that I kept getting a buzz on the wrist and a "GPS signal not found" message on the display. Often this was when I was running in more built-up areas, but we're talking streets of houses, and even then I've had plenty of other wearables keep their GPS lock OK in the same areas.

Polar A370: Fitness and sleep tracking

Polar A370 review

So, the heart rate tracker is good for 24x7 tracking, but how does it perform in a workout? I took it for a few runs, and, well, it definitely stacked up against both the Wahoo and Polar chest straps - at least until I pushed past the anaerobic zone.

Even then, the Polar did a decent job of keeping up. In the below example, in the last section on a 5K run I started pushing up past 170bpm and the A370 (on the left) kept reasonably in pace. That said the chest strap registered me in the highest zone for 13 minutes, while the A370 only tracked nine minutes, so it wasn't perfect - which may have something do with what happened on my next run.

Polar A370 review
HR tracking: Polar A370 (left) and Polar H10 (right)

I made a point about water interfering with the HR sensor earlier. Well, it appears that includes sweat. On another run where I was putting the tracker up against the Wahoo Tickr X chest strap and started pushing up past 170bpm and up towards 180, the A370 was noticeably lagging in the 60s. I knew this couldn't have been right anyway - the thumping chest was the giveaway - and sure enough I did a real-time check and saw the difference. I took the A370 off and gave it and my arm a wipe, and then it seemed to find it easier to make its way up again. In sum, the HR is better than a lot of others I've tried, but it's still not perfect.

As for GPS, connection cut-outs aside, it's much better than the A360, which didn't even use your phone's GPS. And even with the small blackouts, it's still managed to deliver a post-run map of my route, so the problem appears to be the connection between the tracker and my phone, and not my phone's GPS.

I really like the idea of A370's Bluetooth broadcasting feature, which lets you use it as a heart rate sensor with other apps and devices, but in practice only the Wahoo app picked it up. Strava and MapMyFitness both failed to detect it, and I'm not sure why that is. I've asked Polar to find out why.

Polar A370 review

A big new thing about the A370 is the sleep tracking, which uses what Polar calls its 'Sleep Plus' technology. You'll get insights too, based on how Polar reads your night and how you rate your feeling the next morning, though this tends to be quite repetitive and seems too guided by whichever smiley face I choose to present how I feel. Fitbit's sleep insights are still top dog for now.

Polar's sleep tracking will break down your night into 'Actual sleep' and 'Interruptions' which is quite a crude binary when compared to Fitbit's sleep cycles, for example, which combine heart rate and movement to detect your different levels of sleep - awake, REM, light and deep. Polar will tell you your lowest HR during sleep, but that's it. Really, it appears to all be done via accelerometer data which, if there's one thing I can tell you after trying dozens of sleep trackers, just isn't good enough. This was something Fitbit was able to activate retrospectively on older devices, so I see no reason why Polar can't make its sleep tracking more detailed over time.

Amazon PA: Polar A370

For now, it comes down to how accurate it is at detecting movement. And it's not bad. Generally I've found it pretty good at telling when I'm drifting off. It's certainly one of the more finely tuned trackers I've used for sleep, but it's not as good as Fitbit's offering. What's more, the post-sleep insights are still lacking. Fitbit's aren't great either, but Polar's rely too much on my own feedback, and even then it doesn't serve me much.

Polar A370: App and notifications

Polar A370 review

You may already be using the Polar app, in which case you'll already know how the A370 will play with it. I've mentioned the all-day graphs and sleep tracking already, but I'll point out that you also get a feed that breaks down your days' activity.

To sync the A370 you need to hold down the button and wait for it to establish a connection (oh, make sure the Polar Flow app is open too). Once that's found it will work its magic, but be warned, I found that it sometimes struggled to make contact, which required me to hit the Bluetooth reset button in Settings.

You can get notifications on the A370 - another thing that have become norm on fitness trackers now - but I stopped using this quite quickly. While you can scroll between messages, you can't scroll within them, so I was getting a lot of texts where I could only see the first couple of lines.

Just knowing who's contacting you may be enough for some people, but I find it a tad annoying. On the plus side, it supports all types of notifications, so if you want to stay connected at all times, you really can.

Polar A370: Battery life

Polar promises four days of battery, but like the A360 I've found that to be a bit conservative. Obviously the more workouts you do with it, the faster you're going to drain it, but I've found myself hovering around the five-day mark. It's still not as good as some others on the market, and that screen is no doubt partly to blame.

How we test

Hugh Langley


Now at Business Insider, Hugh originally joined Wareable from TechRadar where he’d been writing news, features, reviews and just about everything else you can think of for three years.

Hugh is now a correspondent at Business Insider.

Prior to Wareable, Hugh freelanced while studying, writing about bad indie bands and slightly better movies. He found his way into tech journalism at the beginning of the wearables boom, when everyone was talking about Google Glass and the Oculus Rift was merely a Kickstarter campaign - and has been fascinated ever since.

He’s particularly interested in VR and any fitness tech that will help him (eventually) get back into shape. Hugh has also written for T3, Wired, Total Film, Little White Lies and China Daily.

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