I reckon quite a few C25kers know (and appreciate) the value of a kilometre more than they once did. Perhaps you have thought about things like maximum heart rate, resting heart rate and target heart range? Maybe a few people have even done some maths...
Someone asked what we thought about whilst running the other day. It’s a good question. For me, there have been occasional minutes of admiring a sunrise, or laughing at an appropriate lyric, or just blissful nothingness (which I hope to experience more of) - but usually I am very much in the effort of the moment and find myself doing maths. Trust me when I say this is a very strange turn of events. 😳
I put a graphic rather like the one above on my very first post here. Someone commented on how high my heart rate was and I worried a bit that I was exerting myself too much, particularly as we are meant to be running at this mysterious ‘comfortable’ pace. Was I going too fast? Unfit? Just really not built for running?
The weeks have gone by and the runs have varied in difficulty and effort, but my heart continues to drum like a humming bird when I run. I regularly spike at 183.
This tells me something: the oft-quoted formula of (220 - your age) to calculate your maximum heart rate (MHR) is incorrect. I waved goodbye to 37 six years ago. So I did a little investigating...
Well! The 220 formula was devised in 1970 by a couple of doctors on their way to a meeting. They were trying to determine how strenuously heart disease patients could exercise. They culled data from about 10 published studies in which people of different ages had been tested to find their maximum heart rates. Most were under 55 and some were smokers or had heart disease. They were never meant to be representative samples of he population - in fact, people unused to exercising or who have heart disease will often prematurely stop the test, so they don’t get anywhere near their MHR.
The formula was rapidly adopted by the heart rate monitor industry and became entrenched in the fitness world - and in cardiology. Doctors stopped tests when people reached their ‘maximum’ as per the formula, compounding the myth and misleading themselves and their patients as to their true MHR.
The cardiology doctor in the NY Times article said that in fact, more than 40% of patients can get their heart rates to more than 100% of their predicted maximum according to the 220 formula. An exercise physiologist at Ohio University studies rowers and has seen athletes in their 20s with a MHR of 220, and 160. It’s just that some people get blood to their muscles by pushing out large amounts every time their hearts contract; others accomplish the same thing by contracting their hearts at fast rates.
(220 - your age +/- 30) seems to cover it. So... that means my MHR could be anything up to 207. To most sane people/non-athletes, none of this really matters. Experts say we should be exercising in the ‘target heart range’ (THR) of 70% - 85% of MHR for at least 20 minutes, preferably longer, of our workouts. Fitbit uses the formula to calculate our intensity of exercise - peak, cardio and fat burning (I could write another post on these ranges, but will put that aside for now 😆). I found the red spikes on my Fitbit worrying, which is what prompted me to start reading a little...
My target is to enjoy this journey. The maths for me is an exercise in worrying less, rather than more.
Running has turned me into a complete nerdgeek and I reckon that 90% of you will have not read this far 🤣🤓