Jasmine’s Gear Review: Polar M400 GPS Watch with Heart Rate Monitor

I wish this was a demonstration of the M400 syncing, but it is not. Instead this is a demonstration of the M400 not syncing.
Spoiler alert! I wish this was a demonstration of the M400 syncing, but it is not. Instead this is a demonstration of the M400 not syncing.

Just to change some things up, it is time for a completely unbiased review on the Polar M400 running watch. Polar is looking to change this equation: Polar : Hear Rate Monitors :: Garmin : GPS Watches (translation for the mathematically challenged: Polar, known most for heart rate monitor is looking to crack the near monopoly Garmin has on GPS watches). Should you abandon Garmin for an alternative and is the Polar M400 the alternative to Garmin you should try?

As far as reviews go, usually you can expect me to be highly opinionated on these things. I can be trusted to tell you how I really feel. So how do I really feel about the Polar M400? Read on!

If you’ve run with me in the last few weeks, you would have noticed how much I complained about my Polar M400 running watch. I can find lots of reasons to hate on the M400: satellite synchronization doesn’t work most of the time. Polar flow (Polar’s answer to the Garmin Connect website) sucks. In fact, you may have have even heard me refer to this watch as a dud. Yet almost one month later, I still found myself using it for a few simple reasons, some of which are so good, they almost redeem the M400. But don’t be mistaken: an unreliable GPS watch with basic features that don’t work reliably and can’t  synchronize with your training log software isn’t a GPS watch worth owning.

The Good

Let’s start with the reason the M400 is still in my watch rotation.

Accurate GPS

The M400 [spoiler alert #2: when it works] is damn accurate. It is so accurate, it knows exactly which side of the street I am on. It is so accurate, that when the track is overlaid on Google Maps, you can see the route exactly follow the sidewalk. It is so accurate that it can whoop a llama’s ass at 500 yards. I have to say, the accuracy viewed post-run is truly impressive — even compared to my favorite GPS watch of all time, the Garmin 310XT. I haven’t taken the watch out on a pace based workout run yet, so I can’t comment if that accuracy translates into better pacing than its competitors, but let’s just say I’m impressed enough that this is the first thing on my list here.

I did wear the heart rate monitor many times. It was fine, except when it mysteriously dropped out for an hour. .
I did wear the heart rate monitor many times. It was fine, except when it mysteriously dropped out for an hour. .

A1 Heart Rate Monitor

The heart rate monitor is a solid beast [spoiler alert #3: when it works] It is noticeably heavier and bulkier than Garmin’s ANT+ heart rate monitor, but for good reason: it is much sturdier and has much better rated waterproofing. The M400 with heart rate monitor comes with the Polar H7 heart rate monitor. It is waterproof to 30m. It won’t work underwater, but considering that the Garmin’s heart rate monitors don’t hold up to a few showers, this is a notable advantage in durability. As a bonus, the Polar H7 heart rate monitor features Bluetooth LE, so you can always use it directly with a cell phone instead, making for a nice two-in-one. The H7 heart rate monitor is supported directly in Strava and many other fitness tracking Android and Iphone apps.


The M400 actually has track back to start [spoiler alert #4: yep, when it works] This is the only navigation feature the watch contains, but it is 1000x times more navigation than the garmin watches it competes against in the market. I would have dropped  $400 on a shiny new Garmin 620 if you put this silly arrow on it. Here it is on a $150 competitor’s running watch!

Nice Buttons!

It also doesn’t hurt that the round metal buttons are possibly the nicest buttons I’ve ever had the pleasure of pushing on a watch…. Yeah, the buttons. Buttons are easily overlooked until you experience nice buttons. You know how on most watches you fumble to hit the lap button when you come around each lap on a track? There is something pleasant about big metal buttons with perfect smooth movement set perfectly in the watch case. They are easy to push reliably and confidently every lap.

Simple to Charge

This watch charges with a standard micro USB charging cable, just like every other device and cell phone in the modern world. There is no silly charging cradle to lose.

The Band

A Silicon band is a big improvement over the urethane resin bands on every other watch. I remember buying a Timex watch with a white urethane resin band. Within a week, it was stained. My Garmin 210 watchband dried out and broke within a year. I don’t know if it will be as strong, but so far the silicon band is an improvement in every way.

The Price

Coming in at about $165, the Polar M400 would be a steal if … [spoiler alert #5: it worked all the time.]

The Bad

Now clearly I’m not selling you on the dream of the M400. Even though this is a very nice piece of wrist mounted running hardware [spoiler alert #6: when it works], it misses the boat.

The Website (Polar Flow)

Polar Flow is Polar’s web service, kind of like Polar’s Strava or Garmin Connect. It stinks, and I’m being nice.

Syncing Data by Blue Tooth

Synchronization over bluetooth doesn’t work reliably. In fact, it doesn’t work most of the time.  The silly activity tracking feature can’t be turned off. I had it lock up in the middle of a run and say “Something went wrong. Push any button to reset.” I had it lose GPS signal in wide open street immediately after a 5k race.

If you are a runner that like using apps or websites to automatically log your runs, I virtually guarantee you’ll never get this to sync, and Polar Flow stinks so much, I can’t even pretend to sell it to you as a replacement to those services.

Fit Tracking

If you are looking for an activity tracker with bonus running features, you’ll find this activity tracker inaccurate and lacking in detail. Go get a fitbit or Garmin vivo-something.

When It Works

Now to explain all those spoilers.

GPS Accuracy: So while the GPS is very accurate, it only matters … when it works. the M400 seems to have poor GPS receiver sensitivity. I had reception drop out on a covered bridge and even on open clear stretches of road. It is quite possible that the accuracy is an illusion cleaned up by some sort of post-processing magic on the Polar Flow side of things.

The Heart Rate Monitor: While it’s nice and waterproof, the problem with the heart rate monitor that comes with the M400 (the H7) is reliability. On a recent run, there was this mysterious hour and a half in the middle where the HRM was stuck on 119 bpm. Weird.

The Back to Start Navigation Feature: Back to start is really just an arrow that points back to the starting point for the run. It is a feature that was supposed to give me the confidence to go out without a cell phone and know that I’ll be able to find where I started if I get lost. And yet, I recently saw it err by about two miles. That makes me extremely paranoid about depending on this feature to keep me from getting lost. This is one of those things that has to work perfectly or it doesn’t belong.

The Nice Metal Buttons: While I generally like the metal buttons, I will say that the button arrangement of START/LAP and STOP/RESET are reversed from to the industry standard of START/STOP and LAP/RESET, WTF? In addition to being confusing, it prevents you from pushing lap when paused.

Overall, I would say that the unreliability of the features is a deal breaker and that you’d be better off putting your $165 towards another GPS watch.

Any Polar M400 users out there care to weigh in?

***If you couldn’t tell, I was not compensated by Polar for my review. All opinions are my own!

I'm a subelite marathon runner, but I didn't come from a collegiate running background. Instead I'm trying to break into competitive running in my thirties. I write about chasing the dream of running with the elite girls and tell stories of adventures along the way. Watch me chase the next big thing.

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  1. So would you say it was unreliable? Haha! I just got a Garmin 220 and I’m kinda wishing I got the 310xt or the 110. I am very hesitant to try non-Garmin GPS watches after my experiences with Bia and the Nike Tomtom. Other companies just can’t get their products as reliable and good. That’s not saying Garmin is perfect, but they make the best most reliable stuff out there it seems.

  2. Have you tried exchanging the watch for another one to see if a different one would be more reliable? I have the TomTom runner cardio with wrist heart rate monitor and after exchanging the first two at the store for problems with reliability, the third one works like a charm and I have been very happy with it (so far).

  3. Exchanging it might not be a terrible idea. I’ve been running with the M400 since April (?), and while it can be annoying, I don’t think mine is as bad as yours. Eg., my GPS rarely drops, and I’ve never had an issue with the HRM. (The syncing issues and the unusable website address apparently features rather than bugs, though.)

    I also really like the activity tracker. That feature was the main reason I chose the M400 over the Garmin 220–though if I’d known that the 225 was on its way I probably would have waited. I have no idea whether it’s accurate, but it seems to be in the ballpark and that’s all I really need. Filing up that daily goal bar every day, even on rest days, is super motivating.

    Disclaimer: this is the first wearable of any kind that I’ve ever owned. All I’ve got to compare it to is smartphone apps. So maybe I just don’t have a good sense of what’s out there and what’s reasonable to expect.

  4. I tried the fitbit surge and took it back – it measures blood flow as a proxy for heart rate and was wildly inaccurate.

    i exchanged it for a polar m400, but i’m tempted to exchange that too. The heart rate monitor is incredibly unreliable. It’s till quite new but it works no more than 25% of the time – the watch just doesn’t detect the HRM. I agree about flow, it’s rubbish. I would like it to integrate with digifit, a phone app that i just love. I’m having to import the data with a little app i found on the web, and i see that Digifit has an automatic upload from garmin.

  5. My initial runs with the m400 went reasonably well, or so I thought. Now, it consistently takes forever to lock on to a GPS signal. And when it finally does get a good lock, it CONSISTENTLY drops out during my runs.

    I can’t even recall now how many times I’ve wanted to rip the m400 off my wrist and toss it as far I could into the abyss.

    I’ve done updates, and even then polar flow takes longer than a 5k run to sync.

    The only reason I endure it now was coz I told my wife this was much better solution than running with a iPhone in your hand, gave better GPS performance and thus, worth the investment.

    At least my old Nike GPS watch did its job regardless of its sometimes questionable accuracy. But the m400 rarely stuck with me all the way through a run…

    Well, I guess at least it’s consistent…