Advanced Heart Rate Monitors

Two things that raised my heart rate in Florida!

Most know me as a "training equipment geek" as I tend to have a pile of gadgets I use for my training purposes. Yes it is an expensive hobby but so are so many other things in life like drinking fine wine, HD televisions, cars, vacations etc. I guess this stems back to the days when I began cross country ski racing when I was introduced to "formalized" training versus the flogging nature of soccer I was involved in as a youth. One of the first gadgets I remember being introduced to was the heart rate monitor (HRM). Back then Polar was just coming out with their first commercial units which were big, black and boxy on the wrist. I was amazed at what it was telling me - my heart rate (HR). I remember during training sessions with other athletes where we were all trying to achieve the highest HR for some feeling of superiority over one another. The coaches imposed "target zones" on each of use which was based on the formula 220-age and set the monitors to beep every time we fell out of the zones. We somewhat became "slaves" to the numbers and often found ourselves moving really slowly to maintain our "zones". To this day I still see people subscribing to this school of thought without any regard for their performance - I realize I am opening a can of worms now with that comment...

It was also back then when I bought my first HRM, not a Polar but they should all do the same thing right? What I found was frustration in using the unit. It apparently had "dead spots" which meant that the wrist unit could not pick up the signal sent out by the transmitter on my chest if say my arm went behind my torso as typically happens during running or cross country skiing. It was also unreliable on the bike, roller skiing, walking and the only time I read numbers I could trust was when I was lying down measuring my rest HR. Fast forward a bit, I traded the HRM to another triathlete for a wheel cover to make-like a disc wheel and then bought a Polar Vantage XL. Lesson I learned from that time is that not all equipment is created equal nor does what it purports to do. Hmm, I later learned in university the concept of validity and reliability which kind of guides my thought processes in purchasing equipment.

The past month and a bit I have spent some time reading up on various pieces of technology to use before, during and after training. I am not meaning for this write-up to be a "plug" for the equipment I talk of so please don't assume I get something in return for writing about them. Specifically I have been interested in the Suunto T6 and Polar RS800 HRM. Now as most know, these days power meters are ruling the roads and are evening finding their way onto mountain bikes and rumors abound of a power meter being developed for runners. There is a software program that will allow us to calculate running power and swimming power - too cool but way too much work for the commoners.

So what is so "cool" about these two HRMs? Well it is certainly not the basic HR feature but rather the ability to record, measure and interpret heart rate variability (HRV). Check out the following link to understand this concept a bit more http://www.firstbeattechnologies.com/index.php?page=121. What is intriguing about this is the prospect of looking at the effects your training has on your heart which is to a large extent the "motor" of or body or if we probe deeper how the training affects your autonomic nervous system.

There is a difference between the Suunto and Polar technology in that Suunto measures training effect (TE) and EPOC which are the outcomes of your training session so it provides a somewhat objective measure of how much "fitness" via TE you have gained and provides a measure of "fatigue" via EPOC. The Polar does not directly measure these variables but rather looks at what your heart is saying while you are at rest. For years I have heard cross country skiers using the Polar s810 HRM to help determine if they were ready to go out and train hard on a given day or inform them of the need for an easier training day. So the Polar provides a somewhat objective measure of how rested you are and your body's readiness to train.

I use the term "somewhat" a fair bit because these units are not without their "quirks". First they do not measure your true performance on a given day as a power meter would do which is a truly objective measure and a proper measure of intensity. Rather they measure the "strain" your body is under from the stress applied. Second, both units require the input of variables such as age, weight, height, activity level, VO2max etc. This is where the "somewhat" comes in (especially with activity level) as you make a determination of your activity level based on the hours per week you train - the Suunto guide is a bit confusing as the activity level I should input by their definition does not make sense. For example I train between 9 to 12 hours per week now which is what they classify as an 8.5 but their definition sights that National level athletes are at this activity level - clearly I am not. So the constant used is not precise. I assume so long as it remains the same that it will report in a reliable fashion. However this leads to the next quirk in that our HR doesn't really change much with training especially in those who have been consistently putting in the work. Now when we measure power output, we can see dramatic increases or decreases overtime to which allows us to quantify our training more effectively. The following link contains everything we wish to know on this concept http://www.cyclingpeakssoftware.com/power411/. Since our HR tends to have a ceiling on it TE may be a questionable measurement since the constants will always be the same unless you change activity level but how does one know if the change is meaningful? My assumption is that the unit uses the measurement of HRV to help differentiate training sessions and if this is the case it may well end up being a great tool to measure one's physiological responses - time will tell. I was in Florida for two weeks and I did one run in which I averaged the same pace as I do here in Calgary but my HR was 8-12bpm higher than usual due to the heat and humidity. Several days later and with higher humidity, I did the same run at the same pace but this time my HR was 20-30bpm higher than usual. It would be interesting to see if the TE and EPOC scores would have been similar since pace was the same or vastly different - I assume the day my HR was really high it would have reported a high TE and EPOC as it would have assumed I was racing that day. This would have been a great test of the unit. No I won't be rushing out to buy one at this time but will keep my eyes on it to see how it evolves.



The interesting thing is that I have a Polar CS600 which has the HRV function (Own Optimizer) but their software bundle does not provide the features that the Suunto does. The link I provided above from Firstbeat Technologies does allow Polar users the ability to measure TE and EPOC, making the Polar a bit more expansive in it's features. I played with the trial version for a bit and it was a neat way to look at things. The trick to getting reliable information from the Polar units is to take a series of baseline resting measurements when in a truly rested state first before using it extensively. This makes sense as it needs to be properly calibrated to your heart rate or more specifically your autonomic nervous system. In theory you should see the numbers reported from the Own Optimizer test change based on the type of training you do as it keeps track of the "trend" in measurements. Still, it is hard to take the time to measure properly everyday and is a bit tedious for those of us with kids jumping on you in the morning or when the alarm doesn't go off setting you back by 30minutes. If anyone reads this and has used either of these units to full effect I welcome the 411.

I wish to wrap this writing up so will speak about the iBike in the future as I eagerly await the Generation III unit to arrive.

Now for a formal "rant" about technology. As I have been researching these units the frustration that comes about is how many units are simply incompatible with one another. Specifically, I was interested in the Suunto Memory belt as it is on the AnT communication system so I thought "hey, it should work with my Garmin Forerunner and iBike since they are also on the AnT system". Alas, there is AnT and AnT+ Sport meaning the Suunto cannot communicate with the Garmin which is too bad. Polar is in their own world with W.I.N.D. but what is interesting is how several manufacturers are actually coming together and making their various products compatible with others - for example you can use the Garmin 705 Edge with the iAero, Quarq, PowerTap, SRM power meters and even the iAero can become the computer head for these wireless power meters. How cool is that? Since they all communicate on the AnT+ Sport even the HRM straps can be used seamlessly after "learning" them. So it would be great to have the ability to pick a HR strap that works with "my" computer head which works with "my" power meter versus wearing one HRM set up and then having the power meter which now can not read my HR so my files are all "incomplete" and I need 3 different computer programs to download into...

Perhaps giving all the gadgets away and simply going old school would work better??

Key message this time around is to really research the equipment for features you NEED, understand how to use the key features you NEED, actually use the features you NEED and somehow learn to integrate what the equipment reports with your internal CPU. Remember these are tools to help you learn more about yourself and how your training affects you and should not become your "crutches". Some of my most memorable rides or training runs happened when I just "went" and enjoyed the experience due to the battery dying on me. I just hope I didn't set a PB that day as I would have no way of proving it to anyone.

JVD