Running - heartrate

December 21, 2012

Monitoring your heartrate

You can of course put a finger on your neck, find your pulse, and count and use your watch. Most people though find this inconvenient while working out and buy a heart rate monitor.

The big name in heartrate monitors seems to be Polar.

I bought a well reviewed and cheap "Omron" unit, the HR-100C (for $33), made in China, and it served me well. It displays heart rate or time, and I don't need the time feature. Fancier units have extra frilly features. For example they can be programmed with your MHR and a desired zone and nag you if you don't stay in the zone.

The Omron is the sort where you wear a chest band and also a wrist mounted receiver. Later I got a Fitbit, which you simply wear on your wrist. Since then I have never used the Omron, and don't even know where it is! An Omron or Polar is almost certainly more accurate, but for my purposes, the convenience of the Fitbit wins big time.

Maximum Heart Rate

Once you have a unit, you can entertain yourself endlessly on runs and other forms of exercise. Ultimately you will want to know your maximum heartrate and will then attempt to stay in some target heartrate zone, which is a percentage of your maximum.

Take 220 minus your age (160 for me at age 60).
This yields a conservative value, safe for out of shape people.
Take 217 minus 0.85 * age. (166 for me at age 60). This is "Millers formula". Add 4 if you are an "elite athlete".
Take 208 minus 0.70 * age (166 for me at age 60). This formula is for in-shape people under 40 years of age.
Take 205 minus 0.50 * age (175 for me at age 60). This formula is for in-shape people over 40 years of age.

All the above are just suggested first stabs at the true value. I find I can readily go beyond these values, which means that either I am in better shape than these rules of thumb would indicate, or else (much more likely) that I am just somewhere else on the bell curve due to genetics. Of course, I prefer to believe the former, but in the back of my mind suspect the latter may play a part.

It is well documented that there is significant variation in maximum heartrate, even among individuals of closely similar age and conditioning. For example among an olympic rowing team of men in their 20's a range from 160-220 was observed.

What I intend to do is get out at some serious levels of exertion, monitor what my heart rate is, and keep some records. I am told it can be dangerous to push to your maximum heart rate. Apparently it is a way to find out whether you have heart problems the hard way. I have pushed myself to my highest levels hiking steep uphill trails at a sustained pace, not by running.

The following is suggested as a way to determine your maximum heart rate. Note that this can be risky if you are overweight and/or out of shape. Don't blame me if you do this and die of a heart attack. First warm up. Then run for three minutes as fast as you can. Then just "jog" for two minutes. Then run again for three minutes as fast as you can. (Do this on a track or some controlled environment, perhaps with others around to summon the medic). Your maximum heart rate is the maximum rate during the second three minute run.

Back at it again 1-6-2012 on a bike ride. Before the ride my rate was fluctuating between 60 and 71 (so call it 65) - this fluctuation seems to be some quantization anomaly of my heart rate monitor. During the ride my heart rate was 135-155, and probably spiked as high as 160. Now, lets say that at 155 I was at my anaerobic threshold, then my maximum heart rate is about 194. The formulas say 161 or 170. I am not sure what to think yet.

At it again 12-21-2012. On a 1 hour bike ride, I was cruising along, breathing deeply and steadily with my heart rate in the 120-130 range. With some effort climbing a hill, it rose to 135 or so. Also after an easy 1.5 mile run, my heart rate was up to 135-140.

Let's say that my maximum heart rate is 175. Then my 65-75 percent target zone would be 113 - 131. This fits pretty well with my recent bike ride, but my runs put me up at 135-140, which is a bit too fast.

Resting Heart Rate

Sitting here relaxing (June, 2011) and typing this my heart rate is 64, but sometimes gets up to 68 or 70 for no reason that I can explain. This was measured with the Omron (I got the Fitbit in late 2016).
Checking it again (April, 2021) it is 65, but bumps up to 70 now and then. This is measuring with the Fitbit.

A "normal" resting heart rate is in the range 60-80. Note that some elite athletes have much lower resting heart rates (Lance Armstrong is said to have a resting heart rate of 32).

Intensity and Zones

Beyond the amusement aspect of monitoring your heart rate, the idea is to target a level of intensity for a workout and then make sure that you neither overdo it or loaf. RPE (rate of perceived exertion) is how hard you feel you are working out - and for someone honest and experienced should correlate with measured heart rate. Most experienced athletes without heart rate monitors are very well tuned in to their RPE.

There are a multitude of systems to categorize workout intensity, and they tend to define either 5 or 6 zones. Most systems seem to agree that 80 percent of your max heart rate is the anaerobic threshold.
Here are some target heart rate zones:

65-75 percent - easy and long, spend 80 percent of your time here.
87-92 percent - tempo training.
95-100 percent - interval training.

Here are some target zones for different length races:

10K - 92-94
half marathon = 85-88
marathon = 80-85

Here is another system, based of "PE" (perceived exertion). This is very handy and worth correlating with what your heart monitor is telling you.

50-60 percent of MHR - easy walking, free conversation
60-70 percent of MHR - can only speak single sentences
70-80 percent of MHR - "aerobic zone" - can only speak short phrases
80-90 percent of MHR - "anaerobic zone" - gasp single word
90-100 percent of MHR - red-line zone

Most exercise should be taking place in the 70-80 percent aerobic zone, and some writers break this into several zones. I have been studying triathlon training books by Joe Friel and he defines zones as follows -- he never comes out and defines them based on maximum heart rate, but by analyzing his tables, the following seems close to correct:

Zone 1 "Recovery" - anything less than 70 percent MHR
Zone 2 "Extensive Endurance" 70-73 percent
Zone 3 "Intensive Endurance" 73-76 percent
Zone 4 "Sub-Threshold" 76-80 percent
Zone 5a "Super-Threshold" 80-83 percent
Zone 5b "Anaerobic Endurance" 83-86 percent
Zone 5c "Power" 86-90 percent

Have any comments? Questions? Drop me a line!

Tom's home page / tom@mmto.org