My body is a machine

This song is the best song ever written about glycolosis: the basic mechanism by which the ‘engine’ of the human body takes in ’fuel’ and enables ‘it’ to do ‘work’. 

Although I never studied it at school, I have known for a long time about the basic mechanism by which the ‘engine’ of the human body takes in ’fuel’ and enables ‘it’ to do ‘work’.

But only recently I have become aware of how the ‘engine’ of my body works, and what it feels like when it doesn’t.

As a slightly overweight (86 kg, 1.75 m) 54-year-old male I am aware that I am entering my prime heart-attack decade. Exercise is apparently the key to reducing my risk, but I have not been doing much of that lately: you know how it is.

And whenever I had tried to exercise by jogging at what felt a comfortable pace, I would find that after maybe half a mile I would find my heart racing, I would be out of breath and would need to slow down dramatically – even stop. I assumed that this was a symptom of early-onset death.

However, recently I decided to try this running lark again and popped into the local ‘Sweatshop’ where a very enthusiastic young man took pressure patterns of my feet as I stood on a glass plate, and then made videos of me running on a treadmill. All very high tech. He then sold me a pair of embarrassingly expensive running shoes.

And as an afterthought I bought a £50 heart monitor. It consists of band that goes around my chest – which detects the electrical signals associated with each beat of my heart – which is wirelessly linked to a watch which displays my heart rate.

Suitably equipped, I began to investigate how the engine of my own body was behaving.

The first number I looked for was my resting heart rate. I tried the monitor out throughout one whole day and found that – perhaps surprisingly – my lowest heart rate did not occur lying in bed in the morning (67 beats per minute or bpm) but instead at a planning  meeting at work (60 bpm). This is a healthy number and I was relieved. But maybe I need to contribute more to meetings.

All the web sites frame heart rates for exercise in terms of maximum heart rate. This number varies from person to person, and declines with age. A little reading told me that the typical value for a 54 year old male is around 170 beats per minute (bpm) And based on this I should be exercising at around 140 bpm.

And so the second  number I had to find was my maximum heart rate. This turned out be closer to 195 bpm which I think is basically a good thing. And based on my maximum heart rate, the web sites say I should be exercising at a much faster heart rate.

The sites predict that I should experience a transition from aerobic to anaerobic exercise at around 165 to 170 bpm. And when I ran I could feel that change exactly where it was supposed to be.

Using the monitor I found that if I jog at 165 bpm I don’t go very fast, but I can sing to myself and feel barely out of breath. I can basically run until I am bored.

But when my heart rate reaches 175 bpm I find myself shorter of breath and can either tough it out or relax back to a more manageable 165 bpm.

So the key to understanding my experience of what my body was doing was to make a measurement not of my speed of running – but of my heart rate. I guess it is equivalent to watching the rev-meter on a car instead of the speedometer.

And as result I have been able to run local roads on a course that lasts 5 kilometers: further than I have ever run before. And at the end I still have energy for a not very impressive sprint. (It’s not the time that I care about – its just I would like to give my neighbours the impression that I have been running at that speed all the time)

And the reason I am writing this is because the experience has left me feeling mildly empowered and slightly relieved. Understanding what I was experiencing and being able to relate it to what other people experienced was comforting. It’s just another example of Kelvin’s maxim that until you can ‘put a number’ to something, you do not truly understand it.

And the good news is that the device is telling me that, rather than being close to death, I instead have the heart of younger man. So as long as he doesn’t want it back any time soon, that’s great!


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