As you get older your body stops retaining muscle less and less, this is why you rarely see bodybuilders or athletes compete over 40 and almost entirely never do you see someone over 50! There is a team scientists who study why this is, they study the health benefits of strength training when you’re over the age to properly do so. The human body both young and old create muscle the same exact way but, the older you are the less effective the biological process of making muscle becomes.This isn’t to say that when you’re older you can’t build muscles, you can still build muscles but it will take longer, and you’ll need to be a lot more consistent. It’s easy to see that working out makes your muscles bigger, but what is actually happening? Everytime you contract a muscle especially when you have to work hard to do the contraction, like when lifting weights the action causes changes to the levels of various chemicals in your muscles. In addition to the chemical changes, there are also specialized receptors on the surface of cells that detect when you. What the doctors found while studying people who work out is, when a kid works out the brain sends out a strong signal to the body in order for that muscle to grow. As you get older that signal gets weaker and weaker.