"You live longer once you realize that any time spent being unhappy is wasted"
- Ruth E. Renkl
What Happens When You Exercise?There are times when you can take a very complicated subject like muscle physiology and metaphorically simplify it for "Dummies". No, this isn't meant to be a degrading of any one's intelligence, but rather to create a means to memorize any subject easier, longer, and more comprehensively. Let's get started.
An army is composed of soldiers and a muscle is made up of muscle fibers. These are the basic units to start with in our discussion. Some of the soldiers drive tanks, other's are in the infantry and some man anti-aircraft canons (or guns). The soldiers are given specialized tasks. Muscle fibers are grouped together to form different muscle bundles that also do specialized work. The quadriceps extend the leg, and the hamstrings flex the knee joint while extending the hip joint.
Exercise is basically "medicine" for the muscles, but cause the muscles to respond differently than you may imagine. Exercising does not build muscles, it causes a break-down process called catabolism. There is microscopic bleeding, tearing, and irritation of the muscle fibers. This process is magnified and enhanced during high intensity training (HIT). When you leave the gym the muscles are repaired by nutrition and rest, especially sleep. The results are in muscles that are enlarged (hypertrophied) and increased in number (more muscle fibers are formed; hyperplasia). This process is a building stage called anabolism (as opposed to catabolism).
So if you want a strong army you need many soldier's that are trained, physically, to fight, endure, and "win the battle". With exercise, you want to recruit as many muscle fibers as possible, train them, with the result of having a stronger, healthier and firmer body. The human body is really a muscle machine designed to move.
There are specialized organelles, mostly in muscle, called mitochondria. They are responsible for developing energy to move the body, run, stretch, play tennis, etc. When people go on weight reducing diets, besides loosing fat, they also lose muscle tissue. It's essential to exercise when going on a diet, as it is all the time during your life in your body. If there is a sizable reduction in muscle substance, energy production is reduced, and can lead to a life of the "couch potato".
There are many other benefits of exercising and books have been written of this subject. Kinesiology is the study of muscular movement and physiology. It is a subject major in many colleges and universities.