system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does cardiovascular health improve through cardio/aerobic exercise? Especially for those with clogged arteries from years of a sedentary lifestyle and poor dietary habits. What does the body do to correct this?
gpt
In order to move, your muscles need energy. A key piece in making energy is oxygen (like how you have to blow on a fire to get it to start burning). That oxygen comes from the blood. The blood comes from the heart.

When you exercise, the heart pumps harder. If you keep exercising, the heart gets better at pumping like all the other muscles in your body. With a better pump, you can get more blood with oxygen to the muscles.

But what about the clogged arteries? The blood can’t get there if the arteries are clogged. So your body can literally make new blood vessels to get to the muscles that are working.

These are called collateral vessels if you want to learn more.