Low Heart rate on the bike…and what to do about it! Part I

1 Jun

Low Heart rate on the bike…and what to do about it! Part I

I received a letter from a lady new to triathlon, and it struck a chord as she has a similar issue to me. Both of our heart rates on the bike are much lower than while running. I have summarized her letter below. 

Mary was a top class runner with a 2.42 marathon and after that, 15 years as a successful rower. She will turn 50 this year.

“…running 3 x week similar my heart rate goes up to 160 maximum but on the bike even busting a gut my maximum heart rate is only 140. Usually hard intervals are 136 and a steady ride with a cadence of 90, the heart rate is only 110! – am I missing something – or is this because I am such a novice cyclist!  I am doing turbo sessions 3 x week and get out to ride for 2 hours if the weather is good – I have been cycling for one year.

Question – Do I go on perceived intensity (not very accurate) or do I need a maximum cycle test and then work off those heart rates for the bike? Do I just stick with this and hope the muscles will eventually respond?”

Talking about heart rates, introduces a very complex subject and I will quote my wife and I as an example to show, why we cannot just look up the answer in a book. My resting heart rate is 27.

Now I accept this is incredibly low, but is highlights a problem with training by heart rate alone.

If I double my resting heart rate, it is 54. If I double it again it is 108. Amazingly this is about the maximum pace that I do my easy runs at. It is also a heart rate that I currently find very tough to cycle at. My easy cycling is nearer 90 beats per minute. So, my easy running heart rate is the same as my interval training heart rate on the bike!

Let me take my wife Rieko, as another example. Her resting HR is around 50. If we double it, it is 100, double it again that is 200. This is in fact her maximum heart rate.  Where as I can double my resting heart rate twice and still be doing an easy run, if Rieko doubles her resting heart rate twice she is running all out.

At 27 beats, per minute my body is able to pump enough blood around itself for me to function adequately at rest, while Rieko needs 50 beats.  But for my easy run I must raise my heart rate 4 times my resting pulse, while Rieko must only raise her resting heart race two and half times. So a heart rate of 90 on the bike, although an easy ride for me, is in fact 3 times my resting heart rate. For my wife working at 3 times her resting heart rate, this would give her about 150 beats per minute, which is somewhere near her anaerobic threshold, or her triathlon race pace.

I hope I am starting to show that all our heart rates and bodies are different, and listening to our own body is much more effective than blindly following what the monitor or text book says we should do. Although HRM’s may have some good points they are just a tool, that would be better understood by using them less frequently, and by listening to our bodies more often.