Why do we breathe?
Your body is made up of tiny cells, each of which has a special job
that keeps you alive. Every cell in your body needs a special gas called
oxygen, that allows the cell to get energy from the food you eat.
Oxygen in the air is brought into your lungs. That's when your blood
picks it up and brings it to your cells.
Another gas, called carbon dioxide is a waste product of your cells.
It is very dangerous if it builds up in your body. Your blood
carries the carbon dioxide from your cells to your lungs, to let you breathe
out all the bad gas!
When we exercise, our cells are working harder, and they need more
oxygen. They also produce more carbon dioxide. That's why you
breathe faster when you exercise!
You have probably noticed that when you're exercising, your heart beats
more quickly. That's so that the blood can carry oxygen to your cells
Your heart and lungs work together to make sure every cell in your
body gets enough oxygen.
What do you think happens to the speed of our breathing when we're resting?
When you rest, your cells aren't working very hard, so they need less
oxygen. They also produce less carbon dioxide. This means that
you don't need to breathe as often as when you're moving around. Remember
that because the heart and lungs work as a team, when your lungs are not
working hard, your heart is not working hard either.