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This post was prompted by reading the Guardian’s article about the release of Chris Froome’s performance data on the second rest day of the Tour de France.  For those of you not following this closely, Chris Froome’s dominant performance in the 2015 Tour had attracted criticism that he must be using performance enhancing drugs.  One of the points made in the run up to the release of the data was that he had an unusually low maximum heart rate.  I was intrigued by the following comment in the Guardian:

Of all the statistics the one that probably helps to explain why Froome went so well on the climb compared with other potential winners was his maximum heart rate of 174 beats per minute. Heart rate varies from person to person so it is a figure that is of interest compared only with an individual’s other readings.

But, critically, Kerrison said: “It was equal to the highest maximum we’ve seen from Chris Froome in a Grand Tour, which suggests that he arrived at the climb very fresh.”

because it seemed to imply that maximum heart rate could vary with fatigue.  This wasn’t something I had heard before and I wondered if it meant anything for my own experience: I think I was fatigued when I fainted.  So I wondered if I had raised my HR relatively higher than I had thought.

So I googled about it. I discovered the following

  1. There doesn’t seem to be any consensus about whether exercise changes your maximum HR.  For example, one website is very clear that maximum HR is not trainable and says that as you get fitter you can do more at your maximum.  (Note this article does not address variability with fatigue).  However, I found another website which references a literature review (that I have not read) that says maximum HR actually decreases with fitness.  This isn’t an argument I’ve heard used in the context of Chris Froome, but would actually imply that his low maximum is an indicator of his high level of fitness, rather than something that needs explaining (i.e. the implication that if he can work so hard at such a low maximum he must be cheating in some way).  The article actually quotes the review as saying: “The review reported 3% to 7% shifts with training and detraining. So, for example, someone with a MHR of 200 at the start of the Base period may expect to see their MHR decline to 186 to 194 by the time of their first race.”
  2. There seems to be agreement that fatigue means you would need a higher heart rate to achieve a particular result.  For example, “Greater variations in heart rate occur at times due to factors such as training fatigue, heat and humidity, and dehydration. Understanding how these factors affect heart rate will help you understand how to use heart rate data in a more productive way. For example, you may have a targeted heart rate range as a goal for the day but working within that heart rate range may not be possible if you are experiencing a greater amount of training fatigue.”

So I didn’t find anything to support the idea that maximum HR is related to how fatigued you are, as claimed by Tim Kerrison (not that I have any reason to doubt or challenge him).  However, my reading confirmed that:

  1. I need to be more scientific in my use of HR.  I’ve always resisted this in the past, mainly because it didn’t seem justified given that I’m not actually racing or trying to get that last % of marginal gain.
  2. I’d definitely like to do a treadmill test of maximum HR under medical supervision.  Its important for training properly and working out my HR zones, but I think particularly important given my fainting.
  3. I need to look into conducting a test for my Functional Threshold Heart Rate (FTHR) as this seems to be key to using HR to train properly.

I also had a quick look at my actual heart rate from when I fainted:

  • It was about 160bpm for about 3 minutes.  At the point I remember slowing down it was 152bpm: it had been down to the low 140s after the peak but I think I speeded up after hanging off the back to tell my group that I was going to quit.
  • It had actually decreased to about 130bpm around the time I fainted.
  • Looking back I can see that my HR has been higher on occasion (e.g. 168bpm on the North London Hills ride back in April) though probably not often so high for so long.  However, there was a Regents Park Saturday morning session in January where I was above 160 bpm for about 4 minutes and I then reached that rate for a couple of minutes twice more in the same session.
  • The simple formula for maximum HR (for men) = 220 -age = 171 with a generally accepted error of 10-15 either way.
  • Interestingly, according to the Guardian article referenced above, Chris Froome’s maximum HR in the 2014 Vuelta was 168bpm, so I have something in common with him!

There has also been a recent velonews article about how older (Veteran to a Brit, or Masters to an American) athletes can damage their hearts by doing too much exercise. However, this is about training at a very high level for a long period of time, so I don’t think it applies to me.

In conclusion, I think I should train more scientifically but I don’t think I can yet say that doing something specific would minimise the chances of pushing too hard.

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