Exercise does a lot for your body. One of the main things is that it improves your overall fitness. What does the word fitness mean to you? We all have an abstract notion of what “being fit” is. I cannot speak for everyone but my notion of being fit when I was younger was looking lean, being able to run fast and far, and lift a whole lot of weight. My notion is not that far off from the truth (apart from the lean part), but the truth is slightly more specific.
Being fit has to do with your heart, lungs, blood, vasculature, and muscle cells (amongst many others). It can be divided into two components – the central (heart, lungs, blood, and vasculature) and the peripheral (cells). When you exercise adaptations occur at both the central and peripheral locations that, in turn, help to improve your performance.
The heart is a muscle and like any muscle, will undergo hypertrophy the more you exercise. It is the left ventricle that undergoes the greatest change with exercise. It is the last area in the heart that blood accumulates before being pumped out systemically. It expands in size, allowing for a greater volume of blood to enter during relaxation (diastole) and a greater volume of blood to be forced out during contraction (systole). Blood volume increases due to an increased production of red blood cells which increases the oxygen carrying capacity of the blood. Another adaptation that I find super cool is that you actually increase the number of capillaries in the body. All in all, these adaptations increase the rate of delivery of blood to those oxygen deprived muscles.
Your lungs also undergo adaptation. While you don’t develop new alveoli (the little dudes that make up your lungs), the oxygen diffusion capacity of the alveoli improves (the ability of oxygen to move from the inhaled air into the lungs). This allows for greater volumes of oxygen to diffuse into the pulmonary capillaries, which is a major yippee as more oxygen gets into the bloodstream. The muscles governing the movement of your lungs also strengthen with exercise. This allows for a greater expansion of the thoracic cavity which assists to bring more oxygen into the system.
The peripheral adaptations occur at the site of the cell. Inside your cell there are mitochondria. You may remember from grade 10 biology that mitochondria are the powerhouses of the cell – they utilize the diffused oxygen to produce the necessary energy for the cell. When you exercise, they increase in size and number. Additionally, enzymes associated with the energy production process also increase allowing you to workout more intensely and longer before feeling the burn. Yes, you can actually delay and at some intensities prevent the painful muscle burn from happening. Another major yippee!
When you exercise, you encourage adaptation. The coolest thing is that you don’t necessarily need to perform high intensity exercise to cause such adaptations. All types of activities are associated with adaptations (maybe not to the same extent) but they still help. So next time you’re running, gardening, hiking, raking, dog walking, treading water, skating, lawn mowing, uni-cycling, or three-legged racing you can think about all the changes occurring within your body – the changes that will forever better your health.