Polar V800: Post-Review Update

Since I wrote my Polar V800 review last year, there have been a couple of updates, one bad news and one good news, and I wanted to share them with you. If you have not checked out my Polar V800 long-term review, you may want to check it out before reading this.

As I was saying in my earlier post, I bought my Polar V800 primarily for one reason: GPS tracking accuracy. My aerobic activity of choice has been running, and ever since I started tracking my training runs, I wanted to get reliable measurements of my distance and pace. For those measurements, Polar V800 has been my perfect running companion for just about a year.

But about 6 months into my ownership, it started to give me troubles while charging the watch. First it started out as slight connection problem that can be solved by trying a few different times to clip on to charging cable. Then it progressively got worse to the point where I had to use a binder clip to fasten the charging cable connector to the watch.

After about 10 months, it had gotten so bad that binder clip was not enough. I had to use the binder clip plus crushing pressure to the charging cable connector clip to create a stable connection to charge the watch. And soon enough, even that was not enough.

I had a perfectly functioning watch that I could not charge any more. The watch was as good as a prop! All because of stupid charging cable!

Or was it?

When my improvisational side of brain gave the way to the logical side, I started thinking about why. What was wrong with the charging cable? Could it be the watch?

Then I finally realized that my watch has been expanding. In fact, the reason why the charging cable connector was not clipping on to the watch was because the watch body expanded so that the clipper was not binding to the charging pins.


I suspected that it was the battery that was expanding causing the entire watch to expand vertically. In closer inspection, I could see the watch body was starting to crack because of what-seemed-to-be expanding battery (or something else).

Note that I did not wear my V800 under water while swimming. Only water exposure that it had was during shower a few times a week. Yet I could see the crust forming on the side and around the charging port.

So I did what any gear-loving runner would do. I sent it back to Polar for service request. Since it was under 2 year contract, I sent the watch back to get it serviced. I was hoping that Polar would honor their warranty and replace the battery and cracking watch body for free.

After UPS shipping the watch and a little over a week of waiting, I got a little package back from Polar. To my pleasant surprise, I found a new model of Polar V800 with a new charging connector, thanks to the warranty!


As you can see from the photo, the new Polar V800 has a cover on its charging port, and it has black body instead of chrome.

I had the new watch for little over 3 months. So far it has been charging like a champ, and haven’t seen any other issue with it at all. I hope that continues to be the case.

Happy training, everyone!


Polar V800: Long-term Review

I own a Polar V800 GPS watch. It’s a long story how I ended up choosing Polar V800 out of many GPS watches. If you are in the market for a new GPS watch, it may be an interesting read for you. Here’s the post.

Since the late August of 2015, when I bought a Polar V800, I have been wearing it on almost every run that I went. I just looked up the stats, and I ran 201 times with the watch on my wrist, totaling 1,080 miles. I’ve been using the watch on regular basis, and I thought it may be worthwhile to share what I think about the watch. So here’s my long-term review of Polar V800 watch.

Likes: 1) GPS accuracy, 2) battery life, 3) rugged construction

Dislikes: 1) Flaky charging connector, 2) missing battery life percentage, 3) ho-hum online software, Polar Flow

Let me get in to details.

Like #1: GPS accuracy

I am very happy with GPS accuracy of Polar V800. The primary reason why I decided on Polar V800 was the GPS accuracy, and I still feel that I made the right choice with Polar V800. I frequently hear of other GPS watches with much more bells and whistles, but still yet to find one that tracks the GPS location as accurate as Polar V800.

It tracks the location so accurately that I can retrace whether I was running left or right side of pavement. It’s so accurate that I can pinpoint exact locations where I had to veer right to get off the pavement to avoid pedestrians. It simply works to track each step of the run. Amazing.

Using the watch over 200 times, I do see a room for improvements though. Sometimes it does not lock in the initial position correctly, and shows a location 30 – 40 ft away from the actual location. Whenever I saw this problem occasionally, it did correct the location after running 100 ft or so. I think it’s because of initial GPS location locking software bug, something that firmware update can fix.

Like #2: Battery life

I have been logging about 4 – 5 hours each week on my Polar V800, and never had to recharge the device more than once a week. It seems to be single charge is enough to last at least 6 hours even after using it over 200 times. That’s a definite plus given how frequently I have to charge my iPhone.

In fact one-week-long battery life is a life saver because of charging problem that I started experiencing with my Polar V800. I’ll get in to that in a minute.

Like #3: Rugged construction

Polar V800 has a solid build quality to it, and it lasts well into its first year. I wore the watch practically every other day running over 200 times, and it still feels as solid as the day that I bought it. With big hour and minute display, it is simple to read, and I like its simplicity and minimalistic design.

As for shock resistance, I dropped the watch once in my shower. Thankfully I had a quick reflex to soften the landing on the tiles by deflecting the watch with my right foot. After the drop, it didn’t show any visible crack.

I do see one dent in the back of the watch, and I think it came from getting thrown around in my gym bag a few times. It’s very minor though.


Dislike #1: Flaky charging connector

The biggest gripe that I have with Polar V800 is its flaky charging connector. It just does not work after several months. It slowly lost its connection over time with my watch, and nowadays my computer does not recognize the watch is connected even when it’s securely clamped by the charging connector.

I can tell it’s not just me having charging problem from surveying the online forums. It seems Polar is also aware of the problem because it went through a trouble of creating a dedicated online help page about how to troubleshoot charging issues.


This is a potential deal breaker because if charging connector does not work, Polar V800 cannot be charged, and once the battery runs out, it’s as good as a paper weight. What an Achilles’ Heel to otherwise a great GPS watch!

So as any resourceful user would do, I have been improvising my own ad-hoc solutions to get around this problem. What seems to work for me at the moment is to use an oversized binder clip to reinforce the connector clip as shown in the photo. It works for me today, but I don’t know how long it will continue to work because I had to continue to increase the pressure. (It used to work with extra rubber band wrapped around, but it’s no longer works today.)


I just hope that Polar folks are fixing this problem in their next release.

Dislike #2: Missing battery life percentage

Since the connector is giving out on me, I pay attention to how often I have to charge. For some reason, the Polar V800 software designers decided to show the battery life as an icon. Only when it’s 100% full charged or falls below 10%, then it shows the remaining percentage.

As someone who wants to see the remaining battery life percentage on all of electronic devices, this bothers me like a shirt with jagged label sticking out on back of the neck. Why would they decided to hide the numeric percentage? I cannot figure it out.

Thankfully this is a simple change with firmware update. Hopefully the design folks at Polar are listening and will make the firmware update available.

Dislike #3: Unimpressive Polar Flow

One of the reasons to track the data is to keep the data. Once data is kept in one place, there are many interesting questions that one can ask. How have I been improving over time? How am I doing compared to other athletes at similar level? How do pros train, and what can I do differently to maximize the benefit?

These are all possible to answer with data. And that is the promise of cloud stored data. Because each time Polar V800 syncs its data with its server, the Polar server is receiving not just my data, but many other athletes data.

But I see little that Polar is doing to tackle these questions with their Polar Flow software. It’s not clear to me whether Polar Flow is meant as an online data storage, or online fitness coaching tool, or online athletic community. My impression is that it’s trying to be little bit of each for everyone. I see each category as a big field on its own, and wish that Polar focuses on one area and do it well. I personally hope that it is fitness coaching because Polar is a well known brand among serious tri-athletes community.

There you have it. Overall I like my Polar V800. It’s a simple-to-use, very accurate GPS watch. While it has some charging flaws, I think you can still hack the connector (say hello to binder clips) to make them work for you.

Hope it is helpful.

Happy training!


Heart Rate Variability

[UPDATE 12/30/2015] While going over the additional data, I realized that I had a typo in Excel formula while computing RMSSD (Root Mean Square of Successive Differences). As a result, instead of average of all RR intervals, I was using average of only the first and last RR intervals. Oops. So I updated the RMSSD numbers and my concluding comment.


One of the features of Polar V800 is RR Recording. It measures heart rate variability (HRV). Heart rate variability is the differences in consecutive heart rates. For example, if heart beats at t=0, 1, 1.9, and 2.85 second, the heart rate would be 60, 66.7, and 63.2 beats per minute, and the HRV would be 6.7 and -3.5 bpm.

It’s also often expressed as RR-intervals, which is short for R-wave-to-R-wave interval. R-wave is the wave created by heart beat where the peak is found. RR-interval is also known as Inter-beat Interval (IBI). In the above example, RR-intervals (or IBIs) would be -0.1 and 0.05 second. (For more information on R-wave, visit here.)

It is nothing but a calculated value from straight off heart beat measurement. So what’s the deal? Why would anyone bother measuring their HRV?

It turns out that the HRV has been used in psychology experiments to represent how relaxed the subjects are, and how ready they are to deal with external stresses. The greater the HRV is (meaning the greater the heart rate varies from second to second), the more relaxed the subject is. On the other hand, the smaller the HRV is (i.e. the heart rate is more or less constant), the more stressed she is.

If anyone cares to recall their human anatomy class, HRV measures whether sympathetic or parasympathetic nervous system is kicking in. Sympathetic nervous system has to do with fight-or-flight response. It increases heart rate, and dilates pupil among other stress-related physical responses. Parasympathetic nervous system has to do with slowing down physical responses, such as decreased heart rate, stimulating digestive system, etc.

Because the HRV provides a simple measurement of how relaxed and ready we are, some athletes are using it to see whether they are over training. Thinking is that if the HRV shows little variation, we are under stress, and may not be the right time to start the training.

When I found out about HRV, it seemed counter intuitive. I would have thought that if I’m relaxed, I would see little variation on my heart rate.

Another thing that seemed odd to me was that I couldn’t find a scale (even relative scale) of what typical HRV range would be.

So I decided to experiment.

Minutes before my 15-mile run yesterday, I took my HRV measurement to establish my baseline. Not knowing what to expect, I wanted to get a good sample size, and I figured 5+ minutes would have enough sample points (about 300+ heart beats). Also to minimize the effect of other stresses, I took the measurements while lying down.

Here’s what my RR intervals looked like before my run.


And here’s what they looked like an hour and 45 minutes after my 15-mile run.



As predicted by literature, my heart rate varied noticeably more before my long run, compared to the one after my long run.

To quantify the variability, I ran the Root Mean Square of Successive Differences (RMSSD) of the 337 heart beats. (When I was rested, I had about 337 heart beats in 5 minutes.) BTW, if you want to find out about how to compute RMSSD, you can reference this article that I found.

And to measure how fast I was recovering, I took two additional 5-minute measurements, 23 hours and 45 hours after the run, and computed the RMSSD.

  • RMSSD 00:25 before 15-mile run: 25.551 msec
  • RMSSD 01:45 after 15-mile run   :    4.505 msec
  • RMSSD 23:00 after 15-mile run   : 14.396 msec
  • RMSSD 45:00 after 15-mile run   : 42.032 msec

It looks like my HRV drops to about 18% after my long run. Surprisingly I seem to get full recovery of HRV (plus some more!) within 45 hours of the long run!

That’s way faster than what my V800 estimates as my long run recovery time.

Oh well, even if my heart may be willing, my sore feet say I still needed a rest today. 🙂


Stride Sensor

After I tried Garmin Forerunner 225, I realized how much training data I will be missing if I did not measure treadmill running. Although I ended up not keeping Forerunner 225, I remember how it tracked cadence as well as estimated distance without GPS tracking. I say estimated because it often got the distance off, but considering that it was measuring my steps while strapped on to my swinging right arm, it was a neat feature to have.

Anyway, a few times that I tried Forerunner 225 on my treadmill running I knew I had to measure my treadmill running better.

So when I got Polar V800, I was disappointed to find that the watch did not track running cadence. Although there was a mention of cadence tracking feature coming out soon (Polar V800 has built-in accelerometer), as of now V800 does not track cadence yet. And because it doesn’t track cadence, it does not estimate the distance. Ugh.

Considering it tracks steps as part of daily activity tracker features, I know the hardware is capable. I guess the V800 product managers thought that they needed to make the watch more appealing to casual users. But that meant V800 in treadmill running mode only captured heart rate with chest-strapped heart rate monitor. What a waste of hardware.

That’s missing the entire side of equation. Without distance, I wouldn’t be able to track the weekly mileage, and see how many miles I can cover on my weekend long run. Given that I cover 3 to 4 miles per each workout, and I do about 3 workouts a week, that’s about 10 miles that is missing from my weekly mileage. Cadence would be useful to measure also to see whether I’m moving my feet fast enough.

Once I realized that I was missing lots of data, I started to look into stride sensor. Stride sensor is a stand-alone accelerometer that clips on to your shoe lace, and measures the number of steps and step length. Based on the two measurements, a running watch calculates the speed and distance covered.

Thankfully Polar had its own stride sensor that is compatible with V800: Polar Stride Sensor. It supported auto-calibration with V800, which meant that I could just pair Polar Stride Sensor with V800, and V800 would automatically adjust the multiplication factor based on the GPS distance that was measured by the watch.


So I started to monitor Polar Stride Sensor price. Normally it was sold for around $55. For some reason it is more expensive on Amazon at around $67 as of now, but when I saw the price dropping below $50 on Amazon, I pulled the trigger.

Now I do all my in-door treadmill runs with my stride sensor. It pairs well with V800, and tracks my speed, distance, and cadence.


How I Ended Up Choosing Polar V800

My V800.
Photo is a bit deceiving: It’s not a small watch.

When I finally decided that I wanted to get a GPS running watch, I didn’t know what watch I was going to get. All I wanted from a GPS watch was to measure my speed. I have been doing my fartlek for a while, and I wanted to know my pace during my run. Well, simple enough request, right?

So I started searching. I browsed Amazon for GPS watches with the best reviews, googled for the latest fitness watches that just came out, and went through pages of GPS watch reviews on fitness magazines to online communities. And I found a watch that did everything that I wanted, and plus a whole lot more. I picked up a Garmin Fenix 3.

It was around June. It had only been a couple of months since Fenix 3 came out, and I remember that there weren’t any online discounts available. Note that I consider myself a value shopper (my wife can vouch for that), and very price conscious. I hate paying the full price, if I can run some simple searches to find out deals online. But I simply couldn’t for Fenix 3. So I did a very unusual thing. I walked in to a REI store, and pick up a brand new Fenix 3 at its full price. It was $550 plus tax.

Fenix 3 was a great looking watch. It had a bright color screen without any grainy pixels, it featured GPS and GLONASS location (I heard that GLONASS is a Russian GPS that can be used as backup when GPS is not working; never got to test it myself, though), it did navigation, it showed temperature, altitude, mobile phone alerts, and heart rate using the included heart rate monitor. Oh yeah… it also had the speed.

After trying it out for a couple of days, however, I realized that I really did not mean to spend $550 on my GPS watch. Let’s think about it for a minute. When was the last time I went out hiking in wilderness relying only on my GPS watch to find my way back home? Well, it has not happened yet, and I don’t see that happening anytime soon. I knew I had an impulse purchase. Thankfully, REI was gracious enough to take my return. No questions asked.

Then I was back at the drawing board. It wasn’t Fenix 3. Then what would it be? What was the right watch that I needed to measure my speed? Let’s see, I wanted to use a watch for running, primarily for running, and maybe indoor running as well. Yes, heart rate monitoring would be a must. Oh look. Garmin had the new watch that did not require a separate heart rate monitor. Let’s check it out. It was Garmin Forerunner 225.

It must have been July because I remember ordering a Forerunner 225 from Amazon, and receiving it when I returned from a couple of nights in Monterey. Unboxing it, doing a quick setup, and wearing it, it felt solid. It had a very intuitive navigation, and it was easy to use. The optical heart rate monitor was working as advertised when I clicked a button to read my heart rate on the fly.

So I gave it a real try. I took it to 24-Hour Fitness, and wore it three times on my treadmill run. But for some reason, it just couldn’t produce the accurate heart rate reading for me. I would say about 20% of time, it was showing totally off heart rates, something like 220bpm at one time, and on the other times, it was showing sharp drop of heart rate in the middle of the run. After I failed to get a consistent heart rate reading, I realized that I wanted my measurements to be accurate. As we geeks say, garbage in, garbage out.

Forerunner 225 was not meant for me either. After spending about a week of honeymoon, it was back in the box to be UPSed out to Amazon. By then, I was getting a bit desperate to find a GPS watch that would work for me. So I started widening my search, and looked for something that’s simpler, cheaper, and perhaps more reliable.

Then I found Polar M400. It was built for runner, and had all basic GPS functionalities, plus activity tracking and bluetooth message display. And to make it even more attractive, it was sold for under $200. What a bargain, I thought. I found a deal through Google Shopping site, and ordered one. Finally, I found a watch that would be just right for me. No fancy features. Just an honest GPS location tracking, speed, and heart rate monitoring. Just what I wanted. Problem solved. I just had to wait for my M400 to be delivered through ground shipping.

While my anticipation of M400 built, there were a couple of things that happened. A very bad omen, if you ask me. I found the M400 price dropped by about $40 within a few days after I ordered. Bad sign because it gave me an incentive to return and buy it again if the seller was not going to match the price for me (the seller did not agree to do that, BTW). But even worse was to find this damning report by fellrnr. He was basically saying that he couldn’t recommend M400 because its GPS accuracy was the worst out of all the watches that he tested. And test, he did. If you take a look at his report, he goes into science-journal-article level review process to vet the series of GPS watches, and concludes that M400 is not even fit to be called a GPS watch because its accuracy is so bad.


My anticipation turned into a liability of owning a lemon. In reality, I didn’t know whether M400 would be so bad that I wouldn’t be able to get my speed reliably. All I knew was that I wanted a quality device that captured good data. The thought of knowing that there were better options out there, I just couldn’t live with that hanging over me. So I did what any sensible geek would do. I returned the watch, the moment I received it.

Now, at this point a dilettante may have given up on the idea of getting a GPS watch. But hey, if I were a quitter, I wouldn’t be a runner. I had to find a watch that would work for me. So I dug in and read the fellrnr’s report closely. And to my surprise, he found that Polar V800 had the highest GPS accuracy out of a dozen or so GPS watches that he tested. I searched and found a few other articles discussing GPS accuracy, and found that V800 owners rarely complained about its GPS accuracy, while other watch owners had a few negative comments regarding their GPS accuracy.

From then on, I started to monitor V800 price, and found this great deal where it was sold for under $300 including H7 bluetooth heart rate sensor on eBay. That’s how I ended up with my V800.

How do I like V800? I like it very much. I have been wearing it on my run since I got it in late August, and GPS tracking has been superb. Looking at the GPS tracked route, I can see where I cross the street, and even how I ran off the path to avoid pedestrians. With that level of GPS accuracy, I know that my speed is pretty darn close to the real speed that I run.

What about that speed? Well, we’ll talk about that later. Let me just say that I did not regret my career choice of being a geeky product manager. 🙂