Polar M400 Review – For Exercisers Who Wants The Benefits



Heart Rate Functions


Fitness / Sport Features


Ease of Use


Battery Life


Where To Get It

A Deep Dive Into Polar M400 GPS Watch

The team at CardioCritic had great pleasure performing a long term test of the Polar M400, a GPS sports watch with integrated GPS and activity tracker. We both enjoyed using the M400 as both a normal time of day watch and a fitness training tool, so much so that Louise has opted to use one as her preferred

GPS/HRM for daily/personal use. Aimed firmly at the running watch market, the M400 is suitable for all users interested in 5 x heart rate zone training, activity tracker and GPS speed & distance.  The Polar M400 GPS sports watch has been reviewed by Tristan Haskins aka CardioCritic

  • Who Is It For?

  • Video Review

The Polar M400 is for the exerciser who wants the benefits of an activity tracker (like the Polar Loop / Loop 2 ) combined with a comfortable and accurate heart rate monitor belt (like the Polar A300 with Fat Burn and Fitness Improve) and an integrated GPS (like the Polar V800).

It is highly recommended for everyone from newbie exerciser and casual jogger / cyclists to competent club runner and, in particular, those who partake in MULTIPLE sports and want to record activity time against each discipline. It’s the perfect sports watch for anyone who partakes in ParkRunsRace For Lifeclub runningbike ridescrossfit training, aerobic exercise … basically any sport where you wish to monitor speed, distance and effort (heart rate) plus a daily activity tracker with smartphone notifications … If you happen to use Strava then you’ll be please to know that all workouts uploaded to the Polar Flow app (or web-service) can be automatically added to Strava if you wish.

If you do NOT have the need for highly accurate speed and distance feedback and you’d prefer to get heart rate WITHOUT a chest strap then you may wish to consider the Polar A360.

The A360 is an activity tracker with steps, distance, calories PLUS off the wrist optical heart rate sensors. The distance travelled is calculated by sensitive 3D motion detectors called accelerometers. It’s NOT as accurate as GPS, but it will give about 90-95% accuracy…

Polar started selling heart rate monitors in 1976. CardioCritic have tested the majority of Polar heart rate monitors – using them for the first time in 1996.

Main Features and Functions

Integrated GPS technology


The key feature of the Polar M400 is the integrated GPS technology and the combination of both an activity tracker and high performance sports monitoring functions. The daily activity tracker is a real motivator. It’s quick and easy to see how close you are to achieving your daily goal, it will also tell you what you need to do to achieve your total, eg. walk for 45 mins, jog for 10 mins etc.

Run Outside your Normal Route

How many of us run the same route day in day out… this might be because it’s pleasant route, or one that meets the training needs… but how often is it because we don’t want to get lost ? The M400 has a very easy to use “GET BACK TO START” mode. In any GPS sport profile this view will show you by way of a compass rose, arrow and distance how far and in which direction you need to travel to get home. Simple but very effective.

Related Content: Polar m200 Review, perfect for recreational joggers!

220 Magazine – Best on Test Award

It’s not only us at HeartRateMonitor.co.uk that think the M400 is a brilliant GPS runner’s watch, so do the team at 220 Triathlon Magazine. The M400 was voted the BEST on TEST in their review of GPS running watches.

Personal Bests – Personal Records

Who doesn’t like a trophy? The M400 will award the user with a PERSONAL RECORD Trophy each time a personal best is that. That could be your longest bike ride, furthest run or most calories per session.


Don’t forget to take a look at our own Polar M400 video review and image gallery.

More Features

Polar Flow – online web service

Daily Activity Summary

Graphical Summaries

Polar M400 Watch Image Gallery


Top Alternatives

Next Model UP


The next model up from the M400 is the Polar V800 reviewed here. The biggest difference between the two is probably the addition of MULTISPORT support in the V800.

They are both almost identical physically (the V800 has a more attractive/expensive alloy metal case) and everything the M400 does, the V800 also does.

If you want to be able to record ONE FILE with bike/run or swim/bike/run etc (all in the same file with discipline breakdown, transition times etc) then go for the V800.

Next Model DOWN


For those who run looking for something slightly less technical than this model, Polar have their M200.

The Polar M200 is 24/7 activity tracker with wrist based (strapless) heart rate and built-in GPS. For a majority of runners and recreational exercisers the Polar M200 could be the better (and cheaper) option. 

For those with less focus on running on more on exercise and well being Polar have the Polar A300 reviewed here. 

Best from the Competitors

The Polar M400 is one of my favourite GPS watches for runners, cyclists and anyone who partakes in sporting activities, indoors or out. The one thing that puts some people off the M400 is the need to wear a chest strap to acquire your heart rate. Personally, I still prefer a chest strap because they offer near 100% accuracy for near to 100% of the time. However, there is no doubting the convenience of wrist based heart rate monitoring. With this in mind, the best alternative to the Polar M400 (other than the M200) is the Garmin Forerunner 35 and, for those happy wear the chest strap, the Forerunner 25.

  • Forerunner 35 review – wrist based heart rate, no chest strap required
  • Forerunner 25 review – similar functionality, chest strap acquired heart rate

Great for HIIT Training

This Polar M400 is also highly recommended to anyone undertaking a HIIT (High Intensity Interval Training) programme due to it’s 5 x easy to read HRM training zones.


Polar M400 suitable for 90% of exercisers

During our test it soon became apparent that we were testing Polar’s new No1 heart rate monitor / GPS watch for the biggest chunk of the market. It’s such a complete product it really does appeal to 90% of exercisers. At less than £120 (or under $160) for the HRM version it’s not hard to see why this has become an instant hit.

The M400 is for the indoor / outdoor exerciser who wants to keep an eye on daily training patterns, ensure optimal training and recovery. At the same time, the M400 user may want to measure performance metrics like running / cycling speed and distance plus optional heart rate from the Bluetooth HRM sensor.

The M400 is Polar’s most popular heart rate monitor / speed and distance monitor competing head on with the Garmin Forerunner 220 / 230 and even the Forerunner 620 / 630 as an all round sports person’s watch without the MULTISPORT functionality of the Polar V800 / Garmin Forerunner 920XT.

Smart Notification Update (June 2021) : The M400 now has the ability to support smartphone notifications from iOS 8 devices and Android devices running version 5 or later. An alert message is displayed on the watch display when your phone receives an email, text, call or diary event. More details will follow shortly. If you own a Polar M400, please be sure to keep up to date with the latest M400 update notices.

Could Have Been Better?

The M400 is brilliant. Louise has really enjoyed wearing it day in, day out. Lou’s a gardener so she really have put the watch through it’s paces. A normal day for Louise is 44,000 STEPS !! Both of us give high praise to Polar for the M400. For those looking for something like a Garmin Forerunner 620/220 it makes a nice alternative. It also features activity monitoring, something the Forerunner 220/620 don’t have.

If we had to ask for ONE change… just like the V800, it would be useful to have a DAILY ACTIVITY GOAL. We both found that we were achieving our goal in the week… but MASSIVELY OVER-ACHIEVING at the weekend. Most people have certain days they try to train. The ability to set a daily goal would be great.


It was easy to award the Polar M400 a solid 5/5 star review rating as it’s such a complete and competent GPS training watch. The one thing I must say is it’s NOT just for RUNNERS. It’s brilliant for those that run. but it’s equally perfect for anyone else looking to track speed & distance with chest strap heart rate. For the CYCLIST it supports pedal cadence sensors making it ideal for the cyclist looking for a wrist mounted GPS bike computer. Polar have recently launched the M200 with wrist based heart rate, however, the Polar M400 remains a firm favourite of mine and will do for some time …

On another note, something to check out is the polar a370 waterproof capabilities and the Polar M600: cardiocritic.com/fitness-watches/polar/m600-review/

Andrew Wyatt

Andrew Wyatt

Andrew Wyatt from Texas has been the best-selling author in 2014. He was the most appreciated writer in 2015. Different organizations have honored him with different awards and memberships as well. He is a tech shop owner and completed graduation in Electrical Engineering.

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