2012-01-30

An Evolutionary Theory of Excercise

Just over a year ago, the Glacetarium folks were in Iceland. They were awesome. One of the events they organized was an evening of lightning talks, which was loads of fun.

By far the most interesting talk, for me, was a brief introduction to retroviruses and some of the mechanisms our cells support for "controlled" mutations. The talk really blew my mind, because the implication was that evolution is happening inside our bodies all the time.

A year later, I'm still pondering the ramifications.

The super-short summary, is that our DNA is chock-full of fragments which can, with the help of retroviruses, move around, thus enabling or disabling different genes more or less at random. The body seems to tolerate these minor mutations, even allowing some (endogenous retroviruses) to persist even across generations - which implies that they may even provide some evolutionary advantage.

One of the advantages might simply be facilitating diversity and a low level of mutation within our own bodies. This basic concept, that not all of our cells are the same, makes it tempting to invoke evolution to explain so many things.

Take exercise, for example.

When I was a kid in school, it was "explained" to us in PE, that when one lifts weights or otherwise does strength training exercises, that this causes tiny tears in the muscles and when they heal, somehow the muscle gets stronger.

This was presented as fact, without further explanation. But... why? Why would a muscle become stronger after getting torn up? Shouldn't it get weaker? That's what happens when I tear my clothes, they get weaker with every tear and would ultimately fall apart if my lovely girlfriend didn't make me go buy new clothes, dammit.

What makes muscles different?

Internal evolution can help explain this: The weakest cells rupture. The stronger cells divide and take their place. Repeat until super buff!

All you have to do is provide just enough stress to kill off the weaker cells, without destroying the strong ones too - and then provide nourishment and recovery time so the surviving cells can multiply and fill the gaps.

This balance is the hallmark of modern workouts.

The process works in reverse, too: when there is no external pressure favouring strong cells, other traits may become more important, like energy efficiency or (heaven forbid) the ability to store fat as a buffer against fluctuating food supply. This process of flabbification would be slower though, as it keeps pace with the natural lifetime of the cells instead of the artificially accelerated mayhem of a workout regimen. Which indeed matches at least my experience and explains another mystery: why it takes quite a bit longer to go from fit to flabby (that took me about 4 years) than it does to bulk up (3-6 months).

Of course, I am no biologist. I am just wildly speculating here. I don't really know if this is how the body works, and if it is, it's still probably a gross oversimplification. The body probably has lots of other clever tricks to help this process along.

But I find the simplicity of this evolutionary theory of exercise very appealing. It makes lifting weights at Sundhöllin feel almost magical... :-)

Tags: life


Recent posts

...