The body is like a machine in that it has to be run, or it runs down. it has to be active or it will atrophy.

Most of us have seen what happens when a broken arm or a leg is immobilized in a cast. After the cast is removed some weeks or months later, invariably the limb is visibly smaller and weaker than its counterpart.
Another example of use it or lose it.

There are numerous benefits to be obtained from exercise. For one thing, exercise builds muscle. Also, we have seen that exercise - especially strenuous exercise increases the levels of HGH in the body. This makes strenuous exercise an excellent adjunct to HGH replacement therapy, especially when secretogogues are employed.

Exercise and fidgeting also burns off fat, which sets up a cyclical effect we looked at earlier:
HGH helps us to shed fat, and when we shed fat our levels of HGH tend to be higher, which then helps us shed even more fat. And so on.

When we exercise and burn off fat (converted into sugar), we set in motion a biochemical process that, in a sense, runs in the opposite direction of the biochemistry that turns sugar into fat.

You might think of the process as something of a conveyor belt which, when it is running one way, peels off fat molecules and converts them into sugar, which are then to be burnt off to produce energy.