Review: Polar M400 and Flow as an Activity Tracker

Okay, I have a confession.  I am a nerd who loves measuring things.

For workouts, I started with a Polar FT7.  It's a basic training "computer" with heart rate monitor and it did (what it could do) quite well.

For steps, I started with a Fitbit Flex.  For a while I was obsessed with how many steps I made each day and on some days even tried to fit in a few more steps just to make my daily goal.  I also use the Flex to track the quality and amount of sleep.

Most recently, I got the Polar M400.  It's a training computer, like the FT7 (albeit with far more features), and also an activity tracker (including steps and sleep), like the Flex.  My two obsessions of tracking workouts and activity can now be served by one gadget!

It's been a couple of weeks now and I think I can comment on the Activity tracking aspects of the new gadget.  (I might write about the workout features later.)

To give a bit more background, as well as Fitbit, I have also dabbled with Android Wear (in the form of a Moto 360) and Google Fit.  The Moto 360 worked okay but the battery life was a huge issue; at best I could get 16h out of one charge.  That made it passable for counting steps but essentially ruled it out for sleep tracking.  The other problem is that it's a big watch; it sits really high off the wrist.


## The Watch

The M400 is pretty big but looks okay on my wrist, which is probably on the small size.  (I can wear the small Fitbit Flex straps using the last two notches.)  However, there's a photo from one of the Amazon.com reviews where it looks comically big on a small person's wrist.  (That review gave the M400 a low score.)

The design is definitely "sporty".  I work in a tech company with a bunch of geeks so I can wear it everyday and I think it looks fine.  I wouldn't wear it with a suit; that would look stupid, IMHO.

The screen is a bit disappointing.  It's a monochrome dot matrix LCD (rather than segmented), so it's a little more sophisticated than Casio and Timex watches from the 90s.  It seems prehistoric compared to the colourful touch screens on Android Wear watches such as the Moto 360.  It only has four watch faces showing

   - day, date, time and daily target completion
   - analogue time with day of month
   - super large hour and minutes
   - day, date, time and my name.

The last watch face doesn't make any sense to me; maybe Polar was worried I might forget my name.  I find the resolution of the screen to be too low for the analogue face to look good (whereas there are some beautiful analogue faces on the Moto 360).  The small number of options is definitely a disappointment compared to the many customisable watch faces in Android Wear.

The battery life is very good.  Officially it can last 24 days per charge if used only as an activity tracker and that seems very plausible from what I have seen so far.  Battery life is reduced if using the other features such as pairing with a heart rate monitor or its built-in GPS.  I've used it with a heart rate monitor for about 3-4 hours per week and the battery still comfortably lasts the week.  Better still, when I do need to charge, I can use a standard micro USB charger.  (Supposedly Polar designed a special waterproof micro USB connector for this watch.)

It has built-in GPS but it can only be used when I start a training mode.  It can measure heart rate with a Bluetooth Smart (aka 4.0 or LE) heart rate monitor strap such as Polar's HR7.  It doesn't have a built-in heart rate monitor (like the Fitbit Charge HR which I also considered) so though it's fine for workouts there's no way to get 24/7 heart rate readings.  (Not even with future firmware upgrades.)


## Software

Fitbit uses the Fitbit app and Moto 360 uses the Google Fit app.  The M400 uses the Polar Flow app.  The watch syncs to Polar Flow in the cloud via the Polar Flow app on the phone.

Getting started was a bit annoying because I had to install Polar Flow Sync software on my Windows desktop.  Polar Flow Sync was required to register the M400 with my Polar web account.  Once the watch was registered, I could pair the watch with the app on my phone and thereafter I can sync with just the phone.  I wish there were a way to sync directly with the app without installing any software on my Windows machine; I guess there's no way to use the watch with Flow if all you have are Chrome OS, Android and Linux devices.

Also, the Polar Flow Sync software is required to install firmware updates on the watch.  The Flow app doesn't support firmware updates unlike Fitbit's app or Android Wear.

Compared with Fitbit and Google Fit, the first difference I found was that Flow doesn't have separate daily targets for different activity measures.  In Fitbit I set daily goals for steps and in Google Fit I set daily goals for either steps, active time, calories or distance.  In Flow, I just pick one of three levels of daily target (not very creatively named 1, 2 and 3).  Flow takes a combination of Low, Medium and High intensity activity and counts them towards my daily goal.  It's not exactly clear how the different activities are combined, however, I have found that I can reach my daily goal even though I don't reach 10k steps as long as I did some other activity, such as resistance exercises in the gym.  I think this makes sense.  Sometimes I had felt short-changed when Fitbit or Google Fit didn't acknowledge my "achievements" because I didn't make 10k steps even though I had put in a really hard workout in the gym.  Flow will count the workout towards my daily goal.

The other difference is that Flow has a finer-grained measure of Activity level.  Whereas Fitbit and Google Fit both give two counters for "Not Active time" and "Active time", Flow breaks this down into five counters, which based on the icons are approximately "reclining/sleeping", "sitting", "standing", "walking" and "running".

After I have accumulated 10h of activity in a day, Flow will give feedback on the day such as "you're a slacker, you should be more active _but at least you didn't sit around for too long_" or "good job man, you were active and did some exercise" (paraphrased by me).  Maybe I am simple, but the feedback actually makes me feel good.

Overall, I like this combined measure of activity.  I guess I would since it's easier to achieve my daily goals but I like to think that this combined approach is a more accurate measure of the health benefits of daily activy.

Fitbit and Google Fit measure activity and goals day by day; I either reach it or miss it each day.  Flow, on the other hand, can average my activity across multiple days.  In the week or month view on the Flow website, it shows me what percentage of my activity goal I achieved over that period.  This way, if I had an inactive day, I can make it up on subsequent days and still meet the target over the week.

Another useful feature is that Flow can sync its data to Google Fit.  This means that my daily step counts (and some other data) get sent to Google Fit and Google Fit uses this data to fill in those step count gaps when I've been walking without my phone.  In this sense, it does the same as what the Moto 360 did... but much better because of the better battery life.  The nice thing about Google Fit is that it uses the location data from my phone and can use it to infer when I've been travelling by bike.  Sometimes it has sufficient location resolution to allow it to draw the track of the route I walked or biked.

Those are the differences that I think Flow does better.  On the negative side, the M400 doesn't support automatically syncing like with Fitbit or Android Wear.  I have to press a button on the watch to explicitly initiate a sync, and it seems to take _forever_.  Also, at least on a couple of occasions the sync failed: in one case I could rectify it by turning bluetooth off/on on the phone but in the other case I had to unpair and repair the watch with the phone.  I'm hoping the syncing issues are just bugs that will be ironed out and that continuous syncing will be supported in the future.

Of the three, Fitbit still has the best social features.  Neither Flow nor Google Fit allow me to stalk my friends' daily activity nor brag to my friends (assuming they even care) about how many steps I have walked today.  There's also no option to challenge them with competitions as to who can put in the most steps per day.  (Did I mention that I can be competitive?)  I don't think it's really that important but it does make Fitbit that little bit more fun.


## Conclusion

I think overall the M400 with Flow works really well as an activity tracker.

   - Positives:
      - Combines different activities for daily goals.
      - The Flow website can average activity and goal completion by week and by month as well as by day.
      - The same app (and website) shows stats from workouts together with activity.
   - Negatives:
      - Hardly any social features.  Fitbit is more fun.

So what am I using right now?  I wear the M400 and Flex together!  The Flex is small and unobtrusive enough for me to wear it as well, just for the social features.