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Polar M400 Review

Polar M400
  • Editor Rating
  • Rated 5 stars
£90 to £160
  • 100%

  • Polar M400
  • Reviewed by:
  • Published on:
  • Last modified: 2nd June 2018
  • Heart Rate Monitor functions
    Editor: 98%
  • Heart Rate Accuracy
    Editor: 98%
  • Activity Tracking features
    Editor: 85%
  • Running functions
    Editor: 90%
  • Cycling functions
    Editor: 80%
  • Fitness monitoring features
    Editor: 95%
  • Ease of Use
    Editor: 95%
  • Battery Life
    Editor: 95%

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

Polar M400 GPS heart rate monitor reviewed and tested

Released > November 2014

Replaced > Polar RC3 GPS running watch

Suggested Retail price (at time of release) > £149.50

Update > (Dec 2016) For runners interested in wrist based heart rate, GPS and Android Wear performance there is the Polar M600. The M600 is Polar’s first genuine smartwatch powered by the hugely reliable Android Wear operating system. HOWEVER, it is not as technically complete a sports watch as the M400

Update > (Dec 2016) The Polar M200 is more similar to the M400 being based on Polar’s own operating system (not Android Wear). The M200 is a cut down version of the M400 ideal for a majority of recreational runners / exercisers. CardioCritic’s in depth review of the Polar M200 can be found here

Update > (April 2017) Polar have finally released the replacement to the M400 – the Polar M430 is an advanced GPS running watch with wrist based heart rate. Aimed primarily at runners, but also suitable for any other exerciser thanks to Polar’s 100 different Sport Profiles supported by the M430 …

Who’s it for?

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 ParkRuns, Race For Life, club running, bike rides, crossfit 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

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.

Summary of features found on V800 and NOT on M400

  • Training Load (via Polar Flow)
  • Daily Activity breakdown view (base activity versus exercise)
  • Recovery Status (via Polar Flow)
  • Orthostatic Fitness test
  • Jump Tests
  • Swim Metrics
  • Power Pedal support
  • Cadence sensor support (pedal RPM)
  • Bike Speed Sensor support
  • Race Pace (the V800 can PACE you to achieve a distance in a set time)
  • Altimeter (GPS based)
  • Temperature

The V800 also supports POWER monitoring with the optional Polar / Look KEO power pedals. The V800 also supports (coming soon) SWIM METRICS. Additionally the V800 has a more technical ORTHOSTATIC fitness test that involves sitting and standing, plus, following a training session, as well as getting training load feedback the user is also provided with RECOVERY STATUS calculations that alter over time

  • Polar V800 review  – perfect for Triathlon and elite athletes
  • Polar M430 review – everything the M400 does with addition of Wrist Based heart rate monitor – HIGHLY RECOMMENDED

However …. if you are not such a technical athlete / exerciser, want heart rate WITHOUT the need of a chest strap, want the convenience of built-in GPS and also want to extend the connectivity from your smartphone to your sports watch …. then we would recommend the Polar M600 powered by Android Wear.

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. The A300 is an activity tracker with optional heart rate that very effectively helps to guide the user between a Fat Burning intensity and Fitness Improving intensity. It also features the Polar Fitness Test that can be completed once a month to ensure you path to improved fitness is heading in the right direction

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.

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 for HiiT training

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 2015) : 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

Best features?

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.

Polar M400 showing daily activity tracker summary Required activity to meet daily activity target

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.

220 Magazine – Best on Test Award

It’s not only us at 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.

Polar M400 Personal Records - personal best award Polar M400 Personal Best - furthest distance ran

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

Polar Flow – online web service

Polar have always had good software. In the early days it was software you had to INSTALL on your Windows PC or Mac. Then Polar moved away from locally installed software to a WEB-SERVICE. At first the was just about OK, but many people stuck with the locally installed version. Over the last 3 or 4 years Polar have worked really hard on improving their web based services. The M400 is supported by Polar Flow. A FREE online service that lets users collate and share their training efforts.

Example Data – Polar Flow

Here’s an 18 mile bike ride extracted from Louise’s M400. This is the level of detail you can expect to get from this great watch [opens in new window/tab]

Detailed Route map – with summary duration, distance and calories burnt

Polar Flow GPS map view

Daily Activity Summary – showing total steps, active time, time at various activity levels, calories burnt and INACTIVITY stamps :-(

Polar Flow showing an normal work day with 4 inactivity alerts

Graphical Summaries – these graphs can be ZOOMED if required. Detailed time/distance versus Heart Rate, Speed (or Pace) and Altitude. Also shows a breakdown of time spent in the 5 x Polar Sports zones (HR zones)

Details of heart rate, speed / pace and altitude versus distance

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 an 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.

Polar M400 Image Gallery

Video Review

We put together this video review of BOTH the Polar M400 and Polar V800 at the same time. As we had been testing them together it seemed sensible to put the comparisons in the same video. It’s a bit LONG, sorry about that, but if you are in the market for either of these great GPS heart rate monitors then we hope you find it useful.

The M400 (Polar’s Official Video)

Technical Specification

If you want to refer to the full technical specification of this great activity tracking HRM then please refer to the Polar M400 Tech Spec here. If you want to know everything there is to know about the M400, then please view the Polar M400 manual online.

Google Plus Image bin

We have put all the images taken during this review on our Google Plus page here. Please pop over if you want to see some more higher resolution images of the M400.

Polar M400 image bin

Review Summary

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 … is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon properties including, but not limited to,,,,, or Likewise, we are members of other private affiliate programs and may earn comissions on purchases done by referrals at no additional cost for the buyer.