To Run or Not to Run?

I don’t want to run too often because I don’t want to ruin my knees. I don’t want to lift weights because I don’t want to wear out my joints. I have arthritis and I don't want to make it worse. These are things I hear in clinic very often. At first glance it makes sense,. want to keep healthy knees? Don’t pound the pavement by running. Save my shoulders? Don’t stress them by lifting heavy weights. However, if we dive a little deeper into how the body works and what the research says, we find something quite different.

One of the first things is to realize that the body is very reactive in everything that it does. What I mean by that, is that your body is constantly responding to your environment. When any part of the body is strained, it adapts!  It does this to make the strain easier to handle the next time you have to deal with it. The body uses this in every function. When you study for a test or try to memorize something, the strain and repetition in the brain makes new connections. The more you practice, the better you get at something. The same goes for our muscles. The more we work a muscle the bigger and stronger it gets. The more we do cardio exercise, the stronger our heart becomes. This is a wonderful ability that the body has and allows us to learn and get better at dealing with our environment. However, there is another side to the bodies ability to adapt and that is what's known as Efficiency! Your body is constantly monitoring where energy is being spent and where it thinks it can cut energy cost. For the vast majority of human history food was not always readily available. Because of this, our bodies were designed to be able to survive on a very small number of calories when needed. This means that the body is always looking for ways to get rid of wasteful energy use. It’s why muscles shrink when you stop working out, and why you get rusty at the piano when you stop practicing (The brain is an energy hog and uses around 20% of the calories we consume!). Every muscle fiber and every nerve connection requires energy to maintain. Once the body notices that a tissue is no longer being used, it will degrade that tissue to preserve energy and remain efficient. While it might be great to have a near perfect memory and walk around looking like Arnold Schwarzenegger because you never lost muscle mass, the energy requirements and stress on the body would be so large we wouldn’t have lasted long as a species. 

These two modes of building and tearing down work together to make us the versatile beings we are. But modern society has presented an extreme problem that our bodies were never designed to deal with. That thing is probably best described as a cubicle and Mcdonalds. We now have an excess of highly dense processed calories and a total lack of strain on our bodies. As we move through life, our body chugs along still thinking that the current meal might be the last in a while, so it better store those calories from this large meal. It also seems that we aren't using our muscles that often so no need to maintain those. Because remember to your body, less muscles means more energy can be stored! This goes for the brain, and bones as well. If we aren’t learning new things and engaging in social activity our brains will lose connections and we become less sharp as we age. Lastly our bones will not maintain their integrity because they are never put under enough stress that the body feels the need to maintain them.

The long short of it is that we are victims of our own efficiency. We must realize that we are not designed for modern life. We need movement, we need to exercise. We need to have times of rest and we need to remember our bodies are designed to bank calories for a time it still assumes is coming where it will be without food for a while. Give your body something to work towards and it will continue to work for you.