What are the effects of exercise on the cardiovascular system why does the heart increase in size after regular exercise and why do you pump more blood around the body when you exercise?

Answer 1

If I explain it in a way that you can associate it to yourself, it may help you understand how and why it happens. When you increase activity levels, like going for a jog, you need energy, right?

Without energy, your muscles cannot contract, and in order to get energy we have to eat. To make it simple, we eat, our body breaks down that food and converts it to energy so that our muscles can contract. But... our muscles also require oxygen to contract, so we have to breathe -- the energy and oxygen combined allow muscle contraction.

The oxygen we breathe in travels through our lungs where it combines with blood from the heart, and is carried to our muscles by red blood cells. (thats how the lungs are involved).

This is super simplified, but now you have the ingredients. Now look at it as though its your car -- you can only go so far on a tank of gas before you have to refuel. Well, as you exercise, you are burning "gas" (oxygen), and your lungs must work harder to get more oxygen to replace what you used, and because your lungs are taking in more oxygen (which is carried by red blood cells to muscles), you heart will work harder to move that oxygen to your muscles more quickly.

Answer

Respiratory system exercise not only helps your lungs to hold more air, but it can keep you from becoming short of breath. Blood vessels surround the air sac in your lungs too.