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Tech & Wearables

I Tried It: Polar M400 GPS Running Watch

If you're looking for a running watch that has GPS, heart-rate and activity tracking capabilities, we've found your perfect match.

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Polar M400, $180

Top athletes have been improving fitness via wireless heart rate monitoring ever since Polar introduced the first device of its kind in 1977. Leave it to Polar to once again break into the market with a hybrid of fitness tracker that combines what we LOVE about heart rate and GPS tracking with the modern technology that provides 24-hour sleep and activity feedback. Enter the Polar M400.

RELATED: 6 Pros And Cons Of Training With A GPS Watch

If you’re a runner who wants one watch that can do it all, the M400 offers an innovative blend of running and multi-activity tracking, with an optional wearable bluetooth heart-rate strap, alongside tailored daily calorie expenditure, step count—including running cadence (big plus!)—and sleep quality data. Thankfully, it’s water resistant as well, as it started raining unexpectedly during my first test run! I probably could have checked the weather forecast, but it was a refreshing, gentle rain ending with a FULL double rainbow (I only had to scramble to hide my phone).


For training, this watch is hard to beat for its price. Heart-rate and pacing feedback is critical to fine tuning race preparation, and I especially appreciate the added ability to program interval workouts with work and rest periods based on time, distance, or a combination of both, as well as return-to-start guidance. No more getting lost in a new city!

But how does this watch look, feel and function? Well, if you’re going out for the night or wearing it all day at work, it’s not going to blend as nicely or be as stylin’ as the latest Fitbits. However, if you’re a serious runner and don’t mind who knows it (c’mon—they already know anyway since we can’t stop taking about it!), there’s no shame in wearing this superb running watch all day long to track the rest of your activities, too. On the positive side, the watch strap has a soft rubber feel and is available in the color options of white, black, blue or pink. The watch face is easily readable mid-run—even in bright sunlight—with customizable screens to show the pace, heart rate and distance information that you’re most interested. Additionally, it offers the ability to lock in a heart rate zone or a training pace, beeping to indicate when you’re training outside of your desired zone. Through the Polar Flow app, smart notifications can be set up to read across your watch so that you do not miss important information. The watch has a more streamlined look than past GPS watches, yet the same feature that makes it awesome for those fuzzy-brain long runs or speedy fast intervals—a big watch face—makes it less desirable as an all-day anywhere companion; I found it uncomfortable under a fitted jacket.

RELATED: The Right Way To Get Started With Activity Tracking

The USB port on the watch is waterproofed for rinsing, however the thin plastic-rubber USB cover looks flimsy: mental note, be careful not to rip it off! Also worth mentioning is the increased width of the heart-rate strap bluetooth connector. Hello weird lump where there’s not supposed to be a lump! This detachable connector makes for easy cleaning of the soft strap, but the center sticks out ¼-inch farther than my heart-rate strap purchased eight years ago, so 1/2” total, which is not my favorite look as I wear the strap under the bottom of my sports bra. I am pleased that after being rinsed, the strap completely dries in time for the next day’s run.

In short, if you’re looking for an all-in-one device that gives you most of the features of a top sport watch (no more desperate attempts to do pacing math at Mile 21) as well as detailed tracking of customized daily activities including a large selection of sports and training modalities, steps and sleep quality (with or without use of the heart-rate strap), then the Polar M400 is your dream come true. Personally, this watch has become my primary brain on my runs and a helpful, fun monitor for the rest of my day. While I have recently been called “Sporty Spice”—fist bump, 90’s—I’m going to leave it home when my style for the day matters more to me than my step count.

Author update as of July 1, 2016:

After wearing the Polar M400 daily for workouts and most nights for almost two months (and loving it), I heard the watch start chirping repetitively while charging and later noticed that it would no longer charge. The internal memory and settings also reset back to factory settings, besides the time and date. I followed the troubleshooting steps on the Polar website and was able to get a new watch sent promptly, as it seemed to be a faulty unit. When researching my problem, I read of many similar experiences with Polar’s excellent customer service.
The new watch that I received lacks the charging port cover, which at first made me think that it was a scaled-down version. Looking online however, I find that Polar removed the cover on later devices to aid the drying process. This seems to be a good move as I would awkwardly try to keep it propped open on the old one. I do think that corrosion of the port was at least part of the issue with my first watch. 
I also had a little trouble syncing the replacement watch with the heart rate monitor and my phone, but this was resolved after I updated the watch through syncing with the Polar website. It totally made my day that all of my customized settings -including the diary of past workouts- were transferred onto the new watch through the website!
If you have the M400, I recommend rinsing the port after each workout, as they advise, and making sure that it is completely dry before charging. If your watch has a port cover, I think that perspiration can seap into the port and cause corrosion even if it doesn’t seem like the watch got very sweaty. Hopefully you can avoid the corrosion issues that many of us have dealt with!