Run for your life, your body will adapt.
Updated: Jan 3
“In evolutionary theory, adaptation is the biological mechanism by which organisms adjust to new environments or to changes in their current environment. This enables better survival and reproduction compared with other members of the species, leading to evolution.”
One of the most fascinating natural phenomena is the organisms’ capacity to adapt. It’s arguably the single most important trait required for survival. To survive, one simply has to be able to adapt to the changes in their environment. We can see it everywhere around us: birds adapt to changing weather by migrating; comes autumn, trees start preparing for the cold winter by taking nutrients out of the leaves and letting them go. I see it in my field of cancer research too: the most essential characteristic which will determine the severity of the disease is the ability of cancer cells to adapt to different stressors by developing new mutations.
We also see Adaptation in its finest forms occurring in the wonderful intricate complicated machines that are our bodies, particularly in response to increased physical activity. What exactly happens when one starts working out, or increases the load in their workout routine? How does one go from not being able to complete running 5k to finishing a full 42k marathon? How does the human body adapt to this increase in demand?
In 2011, I was in the medical books aisle at the university library, a lost clueless first-year medical student, looking for an answer to a question that was assigned to me by the class leader. I had only very basic knowledge about physiology, but there I was rifling through “Guyton and Hall Textbook of Medical Physiology”, a massive, heavy, intimidating textbook. I was like a child who couldn’t read going through a grownups book, looking only at pictures. That was when I stumbled upon a photograph that caught my attention and left me utterly mesmerized:
The caption read: Large increase in the number of capillaries (white dots) in a rat anterior tibialis muscle that was stimulated electrically to contract for short periods of time each day for 30 days (B), compared with the unstimulated muscle (A).
Which in English means that the picture shows the blood vessels increasing in number in a rat muscle, before and after being forced to contract for a period of time for 30 days.
How did that happen? And more importantly, why did it happen?
When one starts working out or increases the intensity or duration of an existing workout routine, one of the ways that muscles adapt to this sudden increase in demand of energy (nutrients, essentially oxygen) is by increasing the existing network of blood vessels: the channels through which oxygen travels piggybacking on red blood cells. This process is termed: angiogenesis, which breaks down to the etymological roots angeîon: Latin for “vessel”, and genesis: Latin for origin or “production”.
Thus, just like it’s shown in the photograph above, regular exercise stimulates the growth of new blood vessels, ensuring the prompt delivery of oxygen to your muscles when you start working out.
Learning about this, and later about the other marvellous innumerable adaptation mechanisms that occur in the body in response to exercise changed the way I train and evaluate my performance. Now, every time I get impatient and feel frustrated at my slow progress, I remember the before and after picture of the rat muscle, and I’m reminded that my body recognises my efforts, and is trying to keep up, even if it’s so slow it’s not visible to my eyes; it’s adapting; all I have to do is lace up my shoes, go out there, keep at it, and give it time.