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Polar M400 Review – GPS Running Watch – TitaniumGeek

Marketed as a mid level running focused watch, the Polar M400 is capable of recording data from additional activities such as cycling, as well as the broadly termed “indoor activities”. In addition to the individual sporting activities, Polar has also included an activity tracker making this a very well spec’ed sports watch, yet priced in a way as to really cause the competition something to worry about. Read on for an impressively thought out device!

Polar M400 Review – Sleek, black and focused!

Polar has been one of the driving forces within the sports technology market for years – my first GPS watch was a Polar G1, which required a separate GPS module, powered by an AA battery strapped to your arm as you ran

Polar M400 review

Polar FT80


Polar M400 review

Polar G1 GPS module

Sports, and running watches have come a long way since then, and that is exemplified in Polar’s new M400.

To further enhance the M400, Polar has produced a series of updates to the watch since its release, continuing to add functionality – and these have been quite significant feature additions at times

During my time with the watch, I really found I’ve liked using the M400, for a variety of reasons, which I’ll come onto shortly. But having been a long time user of the Garmin 920xt, and the Fenix 3, one feature I sorely missed from the M400 was the lack of smart notifications…and Polar are aware of this omission, hence last month in June, Polar added Bluetooth smart notifications to the M400. In which case, for someone who’s main interested in running and rudimentary cycling activities, the M400 is going to be a difficult device to beat.

Polar M400 review

Even the packaging says – “bring it!”

Similarly when the M400 first shipped, in spite of having an accelerometer, used to full effect in the activity tracking side of the watch, it was not used for calculation of cadence such as on the Epson SF-810, or the Garmin 920XT. a
Originally this functionality was possible but only through a separate Polar foot pod, which felt very Year 2000 given the competition. Like the smart notifications, Polar have added this functionality through a firmware update. Yes it would be nice if all of these features had been present with the initial release, but Polar deserve serious credit for continuing to push increasing levels of functionality to the M400

The device

The M400 is a natty piece of design. It doesn’t really look like a sports watch. Yes it’s clearly a digital watch, but blends in very well with a day to day wear, and most importantly feels very comfortable on the wrist -not surprising given the years of experience Polar has in the wearbables market. The ease of wearing the M400 is very important given the activity tracker on board and the smart notifications, as it can easily double as your primary watch. I personally wore the Garmin 920XT from its release, but found one of my biggest dislikes was its screaming TRIATHLON WATCH design. Thats not going to be an issue with the M400. Similarly, form a size perspective, its right in the middle of the sports watch size charts

Polar M400 review

Middle sizing

Unless of course you want it is something other than black, in which case the M400 does stand out somewhat – its a shame that the bands are not easily swappable – plus there is no screaming yellow, which I’d always take as pure sports option!

Polar M400 review

no yellow 🙁

The screen

The screen is a 128×128 monochrome black and white affair (which actually looks blue and white – although I still like it!)

Polar M400 review

Black and white…or Blue and white

A monochrome screen may sound old hat compared to the likes of Garmin forerunner 220 and Fenix 3’s colour screens. But the M400 is astonishingly crisp and very legible in all lights, demonstrating that great design and engineering is sometimes better than straight forward pixels

The software is immediately responsive on this sharp screen as well. Too often on the 920xt and the Fenix 3 I come across a short lag between pressing a button and the action occurring. With the Polar M400 everything is, well, crisp.

That sensation of crispness is reinforced with the buttons. The buttons of the watch are actually a little soft, and with minimal feedback on their own. Rather than opting for the usual electronic Beep, to confirm a button press, Polar has chosen a delightful electronic click. Clicks which give an almost sharp, haptic feedback to button presses, which are clearly audible, but similarly not too loud of intrusive. in fact, like many facets of the M400, the key noises are just right

On board software

Its vital, given the pace that Polar have pushed out updates for the M400, to sign up to Polar Flow, and download the latest updates for the watch before you use it for the first time

Polar M400 review

Firmware updates are a big deal with Polar

Polar have really excelled here. So far I have not found a sports watch that has such an excellent sports user interface. Garmin tends to be a little to…pro athlete/disorganised, whilst Epson and Ambit are very rigidly functional, but lacking in design flare. On the M400, the software doesnt feel that its holding your hand, just guiding you unobtrusively, which is a good balance. Compared the to the Epson SF-810, that makes the M400 practically cuddly!

Polar M400 review

Stop doing the GPS dance you MONKEY!


When you load up any of the outdoor tracking options, the device tells you the percentage of the way it is towards having a full GPS lock.

Polar m400 review

GPS lock percentage

This might be slightly artificial, as different satellites can drop in and out of the initial GPS acquisition. But it’s still nice to have some form of progress monitoring if you end up having to do the GPS shuffle before the start of your run – which is of itself unlikely to be a frequent event due to Predictive GPS acquisition.

Once the watch has decided which orbital satellites are going to scrutinise your run, you hit to red central button, on the right, and you are off.

During a run, you have access to various metrics, time elapsed, pace, distance and heart rate.

Polar M400 review

Initial running metrics

The initial screens set out on the device are all clear and very legible. More importantly, they are logically set out. There is a lot to be said for customising your displays, I know I’m a real so-and-so for getting the data fields exactly as I like them. But the data fields available on the Polar M400 out of the box seem to work quite nicely – the inclusion of the heart rate and relevant training zones on once screen is a nice touch too. Again, the way the heart rate zones are displayed is easily digestible and accessible to the user.

Polar M400 review

Heart rate zones

All of which is quite good, as it is not possible to adjust the fields on the device, with any changes you desire only being possible through Polar’s software, which then sends the changes to the device, which a little out of keeping with how user friendly the rest of the device is.

Polar M400 review

Setting data screens from Polar Flow

One other issue that fell somewhat outside of the user friendliness vibe the M400 has how the device acts when you pause on your run, be that by pressing the left side pause button, or using the auto pause function. When stopped you can’t see your data fields, instead there is a large pause screen which is not tremendously useful, and quite a surprising finding.

Polar M400 review

Annoying pause screen

When you have finished your run, to tell the device you have stopped by continuing to hold down the pause button. As you do, the M400 gives a 3 second count down, to ensure you do actually mean to stop, and then ends the run. At this point you can see your run summary metrics.


As part of the user interface Polar has “Smart Coaching” which is really great for both the casual runner, but also the more seasoned athlete, who is quite happy to run and let the watch do the thinking for him. To my mind, the best part of this is the Race/Finish Time Estimator.

Most Garmin running devices will give you a prediction, based off your VO2 max, as to how long the watch thinks it would take you to complete an event. As I commented on in the Garmin 920XT review, my feeling is that Garmin is rather optimistic, and thus is a feature I see little use for. In comparison, with Polar’s Estimator, you tell the watch what your intended distance/event is at the start of the run. E.g. 5km, and it will give you a predicted count down of how long it thinks you HAVE LEFT on your run.

Polar M400 review

Set intended distance at the start to estimate remaining time

Now this, I personally think has a great use, if only as a way to push yourself a little more. Having a Garmin tell me that I, theoretically, can run a 5km in nearly 2mins faster than I’ve ever done before is useless to me. Having the watch say it thinks I’ve only 5mins left in my 10km is a great thing to know, but also a great motivator – “Yes I can drop another 2 secs off that estimation – PUSH!!!”

In addition, after every run, you are given a Running Index numb, which as far as I can tell is Polar’s take on VO2 max in all by name, as its related to age, heart rate and pace on the run.


The M400 does have cycling features, but they are relatively rudimentary, and based around the watches GPS, rather than the ability to connect speed/cadence meters which is not possible. So similarly to running you get pace, speed, distance, time and heart rates data.

An indoor cycling options is also available, but without GPS Data, so this is basically a recording of time and heart rates during that training session. As such there is limited useful data that can be taken from this – BUT that not really a fair criticism of the M400 as it is designed as a running watch first and foremost, and not even a multi sport watch at that.

Activity tracker

A little like smart notifications, if you sports watch does not have activity tracking, it’s not really appealing to the current market,

The Polar M400 monitors your total step count using its internal accelerometer, and when you sync the device at the end of the day it will calculate a distance walked for those steps. I still dont understand why that same accelerometer can’t be put to other uses!

I quite like the progress bar which features front and centre on the default clock face, with a small animation, constantly reminding you it’s there, and to move. You can choose other clock faces, but pressing the down arrow, but personally I like the default.

Speaking of clock faces, Polar uses a clock face to visualise your activities in the Polar flow app, which is a novel, and effective visualisation strategy

Polar M400 review

Activity clock

Activities trackers, are about promoting movement, and stamping out the curse of the sedentary life style…through occasionally buzz notifications. Ok that might be a bit strong. But if you do emulate the couch potato, and remain inactive for 50mins, you will get a move notification, allowing you to address that inactivity before its recorded on your daily log, like some kind of bad mark from your electronic fitness coach.

Polar again comes to the fore with the human touch with regard to activity goals. At the setup of the device, you select which goal, 1-3 you want, and rather than base your choice on an arbitrary number, there is a little description of the activity of your possible day, and you opt for the description that fits you best.

Smart notifications

Smart notifications are present, but slightly rudimentary. When a notification comes through to your phone, the M400 gives a little buzz and displays the notification. But one screens worth. There isn’t a way to see anything more than that. Similarly, once you pass the button to dismiss that message on the M400, there is no easily accessible notifications screen for you to look at messages which have been received. But maybe I’m asking for a little bit too much, given that there are smart notifications on the device!

Polar M400 review

Text messages as seen through smart notification

Other bits

I’ve recently extolled the virtues of the Epson charger for the SF-810, but Polar certainly win the award for charging an advanced device, with 30m waterproofing. No fancy induction charging here, just a simple micro USB socket under a rubber seal. Oh and did I mention it’s waterproofed to 30meters!

Polar M400 review

Waterproof USB under then flap

Why can’t other companies opt for something this simple? Yes the rubber seal is not as elegant as other options, and is a potential source of wear to the device…but it is more of an additional waterproofing feature, as the USB port is INTERNALLY waterproofed, so if you do end up pulling the tab off, it should still keep ticking down at 30m depth. Plus using a USB port means I will ALWAYS have a charger available, and a replacement will cost £1 or less.

The down sides

Whilst the Polar M400 may manage to get 8 hours using GPS and a Bluetooth Smart HR monitor…it can only access a Bluetooth monitor, which is a shame. Whilst for most people it may not be an issue, ANT+ support allows not only access to a range of sensors, but crucially allows me to connect with more than one device at once.

When using a TICKR I can have my Fenix 3, the Edge 1000 head unit, and Zwift all receiving ANT+ data, whilst I’m also sending Bluetooth data to my phone.

BUT with Bluetooth only devices, you can only connect to one device at a time. Basically you can go running with the M400 Bluetooth HR strap using your phone, or the M400, but not both.

But again for the intended audience of the M400 the Bluetooth smart works well. When you first set up the watch, after putting in your personally details, you are asked to touch the watch against your HR monitor when you are wearing both…and that it. The sheer act of touching them together makes the pairing, and that’s quite nifty. Yes it’s an established feature of Bluetooth light, but it’s not something I see used very often.

Polar Flow

Yes I’ve included Polar Flow as a negative. Lets be frank, its not  Garmin Connect level bad, not by any stretch of the imagination, it just seems to have a lot of redundancy in it. Again I come back to the simplicity of the M400’s onboard software which just works. Yet Polar produced both the Polar Flow and the Polar Beat Apps…yet neither of these can replace the Polar Flow website, which you need to access for things like changing the data screens.

There are plenty of positives in the Polar flow software, as I say, they are just a little disjointed. One aspect I do like is the activity monitoring information, which is displayed as a clock face. In turn your movement, and crucially immobility markers are shown on that face, and below, an actual break down of your days activity.

Heart rate zones feature prominently throughout Polar Flow software, which is always going to be a good thing, again trying to improve the knowledge and use of heart rate zones to improve users fitness.

Polar M400 review

Polar flow activity screen


  • The M400 is an attractive device
  • Gorgeous screen
  • Responsive and intuitive interface
  • Keenly priced
  • Very much about improvement rather than just recording your activities
  • Well made

Basically unless you are dead set on having a device that supports ANT+, Polar have a winner of a device here – oh and did I mention the internal waterproofing!



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  3. Hi!
    Thanks for the wonderful review!! I’d like to ask about a small point that I read only in you review; you said that the watch can calculate the cadence based on the accelerometer only, without the footpod. If it works, can you view your cadence on the watch while you are running?

    Just a little confirmation before I buy the watch!! 🙂 Thanks a ton!

    • I’ll have to check my wording. The watch ass has accelerometer which is used for the step count. It’s NOT utilised for cadence when running.

      Instead of a foothold are better of with a HRM such as the Wahoo TICKR X, or Stryd that has cadence built in


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