Why does lung volume increase?

Answer 1

The lung volume that increases with exercise is vital capacity. When you exercise regularly, your body is more efficient at transporting and using oxygen, making vital capacity marginally bigger and exercise less difficult than someone who is out of shape.

Answer 2

What happens to your lungs when you exercise is that they absorb more oxygen. This oxygen is then sent to the muscles you are using during exercise, mostly your limbs.

Answer 3

Because when you get older it starts to change and increase.