Rated 5 out of 5 by from LOVE IT!! I've tried many running watches over the past few years including Garmin, Tom Tom, Timex, and Nike. This by far is my favorite watch. Its masculine, fits great, and has many features. The screen is my favorite part of the watch though. I can have up to 4 lines of data on one screen. you can customize the watch via your computer, sync it to the watch and boom done.. I didn't get the heart rate package because I have several monitors, also because it will connect to any "Bluetooth" monitor on the market. So $180 for a watch that compares to others in the 250 and up range is pretty nice. PLUS Polar has outstanding quality in my opinion, and this feels VERY premium. CONS: The GPS time... it can take a bit longer than I want to find a signal but its not that bad.
Date published: 2015-01-02
Rated 5 out of 5 by from Polar has really outdone itself I bought this watch because I wanted a greater amount of data from my workouts, and especially for those backcountry ski and hiking days. I am so incredibly impressed with how well Polar delivers. I am writing this review on Thursday, I got the watch on Tuesday. Right out of the box everything worked the way it should. Easy to pair to your computer, phone, and set up portal online. Tracks sleep pretty well and steps too (though I am convinced that if you walk like I do - with heavy steps - that it adds about 2x times as many). I took this backcountry skiing today along one of my favorite routes. Took a minute to find the signal, and didn't have a single problem thereafter. once you sync the data to the app after you are done, it then syncs online and you can view a plethora of data. One of my favorite features has to be the training notes section and the ability to name a favorite route - for comparison at a later time to the same workout. I could go on forever about this watch, but I would highly recommend it. Unbelievable that for less than $250 (inc tax) you can get a watch that does all this and is not that much larger than about 90% of the other polar HRMs I have owned. Would recommend to anyone looking for an activity tracker, GPS HRM, and who like to analyze workout data for future gains. You won't be disappointed.
Date published: 2015-01-15
Rated 3 out of 5 by from works great when it works very nice product that makes tracking activities simple, love the flow sync aspect with the online tracking of hikes & fitness level. However, the watch will lose sync with the heart monitor an will not re-sync after 4 months of continuous use. I have had this happen to 2 of these units thus far. REI will exchange the unit but you cannot sync your online training activity between the different units which makes tracking fitness' progress challenging
Date published: 2015-05-31
Rated 4 out of 5 by from GPS / fitness monitor is great fun This was purchased to replace a heart rate monitor that quit after many years. The polar heart rate monitor / chest strap is excellent. I am not an avid runner anymore but the GPS is great for running, bicycle commuting, hiking and skiing (keeps track of number of runs and vertical feet). Battery life is excellent unless GPS is used all day. Syncing was somewhat difficult but latest update appears to make that more reliable. The cost is not much more than heart rate monitor several years ago.
Date published: 2016-01-09
Rated 5 out of 5 by from The Perfect Exercise Watch I purchased this after returning a Fit Bit Surge. I returned the Surge because it isn't water proof and when it got rained on it fogged up. I have been using the M400 for a month and it is perfect. First I love how you can customize it with the on-line app Polar Flow. See the screen shot. You can customize what is displayed during your workout and create your sport profiles based on what you do for exercise. Perfect. Second, I love the data it collects and presents. See the second screenshot. Shows the route you took, and your heart rate and speed on a graph. You set your heart rate zones (again you do this on the on line app). Polar flow also lets you know when you need to update the firmware which will likely fix issues other reviewers have reported. I have had no problems so far. Again 100% satisfied.
Date published: 2015-07-28
Rated 5 out of 5 by from Great activity monitor I am avid outdoor person and this watch does everything I need it to do. bought this watch due to its various capabilities of being an fitness monitor, tracking my elevation gains while hiking and tracking my heart rate and calories expended during my workouts. I was using the Garmin Forerunner 15 and this watch cannot compare. Also, being able to use the Polar Flow application to modify the sport profiles to adapt to what training platforms you would like to monitor.
Date published: 2015-07-24
Rated 2 out of 5 by from Frequent Errors I would not recommend this watch. Sometimes during my runs, I get the error message, "Something went wrong. Press OK to reset M400", and then I lose all of the data for the run. A quick review of other message boards reveals that others have had this problem too. I don't think this watch is ready for prime time...
Date published: 2015-06-23
Rated 5 out of 5 by from Awesome Product. Awesome product at an awesome price. GPS/HR, 24/7 tracking + sleep metrics, & built-in Fitness Test. Very happy with my purchase.
Date published: 2014-12-22
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Questions & Answers

Will this watch fit my 5 1/8" wrist and will the band adjust to 33"?

Asked by: PJinNY
The watch band fits wrists as small as 5 1/2 inches. The heart rate strap adjusts down to 24 inches.
Answered by: REIservice
Date published: 2016-09-15

Can this watch be used while swimming? It says water resistant, but would it be a good watch for triathlon training?

Asked by: KaraColorado
You could use the M400 while swimming and there is a swimming mode however there is no lap/distance tracking in either indoor or outdoor swimming. The M400 will also not capture heart rate data underwater. The Polar V800 would be a better choice for triathlon training.
Answered by: REIservice
Date published: 2016-09-30

If you like the watch but not the HR strap, can you return the monitor for the price difference of the package vs just the watch?

Asked by: acc95
We do not offer partial refunds and are only able to return complete products.
Answered by: REIservice
Date published: 2016-08-01

In the Specs, what does "user replaceable Batter = NO" mean?   Does the unit have to be sent in? if so what is typical cost and turnaround time? 

Asked by: Rave On
The battery on the Polar M400 is rechargeable so you will not have to replace it. You should expect about 8 hours of training time or 24 hours of time mode from a fully charged battery.
Answered by: REIservice
Date published: 2015-09-20

Can I customize the display to show what is seen on each line?

Asked by: Crestas
You can customize the data fields on the display of this watch.
Answered by: REIservice
Date published: 2016-10-11

What is the size of the face of the Polar M400? What store in the metropolitan Portland Oregon area has one I can try on?

Asked by: Denny
The face of the M400 will measure 2 x 1.5 x .5 inches. The Clackamas, Hillsboro and Portland stores are showing stock as of 2/24/2015.
Answered by: REIservice
Date published: 2017-01-27
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