Monday, March 05, 2007

Ran another test on my Polar heart-rate monitor

Last Saturday evening I read the users booklet for my Polar heart-rate monitor and discovered that it saves the highest and lowest heart-rate during a workout session. So, this morning I ran a test to compare the reading on the monitor with the maximum value saved. I've been suspicious that the value displayed is an average of some kind, and if so, that value might be less than the maximum heart rate that I achieved during the workout. After running 3/4 mile warm-up at a heart rate of about 90, I ran a half mile split at a pretty fast pace. When I finished the half mile, the monitor gave a value of 112 (my 80% of max is 119). I then checked the maximum value that was saved, and it was also 112. Thus, if any averaging is done, it is probably a moving average over the last few readings, which are taken at a rate of some fraction of a second. The monitor display is uppdated every second or so, and since only a few readings are probably used in the averaging, the averaged result would likely be the same as the displayed value. I thus concluded that the HR monitor can be trusted to give a good value of my HR while running. I did this, because some runners have had problems getting good values from their HR monitors.

I then ran a test on the "10-second measurement" that I described on Saturday. I ran a rest pace and used the HR monitor to see how much my heart slowed down in the first 10 seconds after I stopped (my heart slowed 2 beats). I then ran the rest pace until my HR stabilized, and then I stopped and manually counted the beats for 10 seconds. I added 2 to that value to compensate for my heart slowing down. I compared that value with my HR rate as measured by the monitor divided by 6, and the two values were the same.

I finished my workout with a 2-mile run at a comfortable pace yielding a heart rate of 90. The temperature during my workout was in the mid 50s (F). A really great spring day!


chetkast said...

I have been reading your site all day today; and I'm enjoying it very much. I'm 64 and we've been working out now for about a year on an eliptical, stationary bike or jog/walk depending on mood and weather. Your tips on 10% and heavy/light are great. What the wife and I need is a good heart rate monitor. Can you give us the model number of your Polar? Do you really like it? Thanks for all that you do.

Allen said...

Hi chetkast,

I'm glad you've found my blog interesting and useful. I put a lot of time into the blog, and it is comments like yours that make it all worthwhile.

I have an older model of heart rate monitors, which I think is the RS100 from Polar. Here is the link to a comparison of the Polar Models

I like my Polar except for one thing. It doesn't tell me which zone I'm in. It tells me my HR, but I have to do some calculations to determine the percentage of my max and the corresponding zone. The more expensive models let you input your age, and the monitor does all of the calculations and displays your zone.

If you're not familiar with zones, go to and read about them. They are a good way of determining how hard you should push yourself. I started running in the mid 1970s, when heart rate monitors hadn't been invented yet, and I learned to listen to my body and to control my training by how I feel, and I thus don't use the heart rate monitor on a regular basis.

I have a tutorial running site at that has a lot of good tutorial information that will be of interest to you and helpful to you.

There is a nice running forum at that I visit each day. It is a nice forum. Everyone is friendly and supportive of each other. You might stop by and check it out. I think you and your wife would enjoy it. A great place to ask questions and to get good ideas to consider. My blog has links to my tutorial site and the forum in the left sidebar under a Links heading.