Review of Polar M400 Running Watch

I have had my Polar M400 Running Watch for a full month now. Prior to purchasing it, when I went running, I was actually wearing 3 devices on my arm: a Timex watch which worked with a chest strap heart rate monitor; another Timex watch which allowed for repeat intervals which I needed in order to use Jeff Galloway’s run-walk-run method; and a FitBit Charge HR. In addition to what I was wearing on my arm, I would sometimes carry my cellphone, on which I would run either the Nike+ app or the MapMyRun app. My Polar M400 replaces all 4 devices — and then does things that none of my devices could do.
To state succinctly what I am going to say about the M400: I love it! What an awesome device! I bought it from Amazon ( for less than $160 (without tax or shipping), and it came with a chest strap heart rate monitor. It was around $100 less than its competitors, such as a number of Garmin products, such as the Garmin Forerunner 220.

In addition to accurately reading my heart rate with the chest strap monitor — something I couldn’t trust the FitBit Charge HR to do from my wrist — it has a GPS built in, which seems to sample all of the data I am interested in every second (since I can download the data in a csv file and examine it at that level of detail). I had not really paid a lot of attention to either Nike+ or MapMyRun until the end of the run (I found it awkward to be pulling out my big Samsung Note during a run), while wearing a GPS on my wrist has enabled me to be interested in what it can tell me during the run. In addition to various distance measures, it can also tell you your current speed and your average speed for the lap you are on and over the course of the run so far.

A feature that I hope to not have to use — but one that is very attractive to me as someone who travels for my work to foreign countries where I do not speak the language, but nonetheless try to run in these places — is the “return to start” feature. This, in principle, directs you back to your starting place if you would get lost. I have experimented with this feature around my local runs, and it uses arrows on the display to tell you which way you need to be running.

Another feature that I like is the one that keeps track of your cadence (steps per minute). Many runners tend to over-stride which can stress various joints and lead to frequent injuries. One of the key ways to keep from over-striding is to target a faster cadence. I’ve read that between 160 and 180 strides per minute is the optimal range. The watch can display your cadence so that you can monitor how you are doing.

I really like the watch’s interval timer, which doesn’t require anything more than just that the watch be worn on your wrist. It is possible to set more than one timer, but I only use one for the run-walk-run method (though I know that many use at least two). The timer starts beeping five seconds before the end of the interval so you can prepare to stop (perhaps, in a race, allowing one to find a good place on the road to slow to a walk), with a beep every second, and then a distinct alarm sound when the interval is completed. With run-walk-run, I typically set it for 2 minutes. I walk the first 30 seconds of the interval, at which time I start running (I know when to start because I have the interval time displayed on my watch, and I monitor it). Then when the alarm sounds, I know I have to walk again.

The Polar M400 allows you to customize a number of displays for your use during a run. The customization allows for up to 4 lines per screen. My favorite is the one that shows heart rate on the top, elapsed time on line 2, interval time on line 3, and cadence on line 4. I sometimes switch to a second display that puts distance on line 1, drops cadence, and has heart rate instead on line 4. I did, however, create a third display which I don’t use very often, which shows current speed, speed for the interval, and average speed for the run.

When you are done running, you can upload your data via Bluetooth to your smartphone, or you can plug it into your computer and sync it that way. You can look up your run statistics via your smartphone or internet. Polar provides various graphs that help make interpreting the run easier. It also allows you to export your run data (for one run at a time) to a csv file, if you want to analyze your data further.

The Polar M400 keeps track of your sleep, but I have not found out how to get this directly from the watch, so I have only been able to find it on the internet after a sync has been completed. It has taken me an entire month to find how to see how many steps I have taken during the day (unlike I had experienced with the FitBit charge, since this was one of its main features) — you go to the “Today’s activity” menu on the watch. And seeing how much charge the battery has is not entirely straightforward — it pops up on the screen if you push the button to start a training session.

But despite some features that could be improved through making them more accessible, I have had a very positive experience with this watch, and would encourage all of my running friends to consider whether the benefits that it gives, which I just described — would seem to make it of considerable value, considering the price.

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