The Exercise "Miracle"

There are numerous benefits of exercise, but there's one that is so great that it can only be classified as a "miracle."  Exercise breaks down cells in your body, which may seem like a bad thing, but it's not (it's actually a great thing). Your body clears out the broken down cells, and builds new one. And if you exercise, it senses that your muscles need to be be rebuilt stronger, and it makes them stronger. Exercise is therefore one of the best ways to build and maintain a stronger and healthier body.
     It may seem strange, but your immune system is at the forefront in this change. You no doubt thought that your immune system's main job was to protect you from disease, and indeed  it does, but it's also involved in muscle building. So let's begin by looking at your immune system. I'll try not to get too technical. It actually consists of two systems, referred to as the innate system and the adaptive system. The innate system gives the first line of defense against foreign invaders such as bacteria, viruses and so on. When it detects a foreign particle it swings into action, triggering inflammation that walls off the invaders. The adaptive system is a backup system. If the innate system fails to contain the invaders, it comes into play. It calls up white blood cells called B and T cells to attack the foreign particles. And one of the most amazing things about the B cells is that they have a memory. After the invaders have been overcome, they study them and learn how to deal with them the next time they invade. They're now ready for them; they know what they look like and can attack them immediately.
     But let's go back to the innate system again. The two major particles of this system are called macrophages and dendritic cells. They secret tiny proteins call cytokines which play a vital role in the immune system. They are "messengers" that direct and oversee most of what goes on.
     So how does all this relate to building better muscles? The answer is that exercise and body building stretches and tears muscle cells, breaking them down. They die and have to be replaced, and it's the cytokines that direct and control the reconstruction process. There are actually several types of cytokines; one of the largest group is known as interleukins.
    Okay, let's go back and see exactly what happens when you exercise. With the accumulation of dead cells, one type of cytokines, called inflammation cytokines call in white blood cells to begin the demolition. During this stage the old cells are cleared out and everything is readied for the next stage. In this next stage another type of cytokine called growth cytokines go to work. They make the new muscle cells bigger and more powerful than the ones they are replacing. I'm assuming, of course, that your muscles were exercised relatively hard before all this began. How hard does this exercise have to be? I think it's safe to say that it has to make you huff and puff a little. In essence, you have to challenge your muscles. If you don't, your old, dead cells will be cleared out, but your new cells won't be build bigger and stronger.
     So it's easy to see why exercise is so impotant.