Fact. If you stop exercising for a period of time, your muscle size will decrease. This is because muscle tissue requires a certain level of stress, or resistance, to maintain its size and strength. When you stop exercising, the stress on your muscles decreases, causing them to atrophy or shrink in size. This process is known as muscle disuse atrophy, and it can occur relatively quickly, depending on the length of time you go without exercising.
