The diaphragm is an important muscle that helps us breathe. It has a dome shape and sits at the bottom of our chest.

When We Inhale:

• When we take a breath in, the diaphragm tightens and gets flatter.
• This change makes the space in our chest bigger, allowing about 500 mL more air in.
• As a result, the pressure inside the lungs drops to about -1 mmHg, which helps pull air into the lungs.

When We Exhale:

• When we breathe out, the diaphragm relaxes and goes back to its dome shape.
• This makes the space in our chest smaller, which increases the pressure inside the lungs to about +1 mmHg.
• This pressure pushes air out of the lungs.

The diaphragm is very important! It is responsible for about 60-70% of the air we breathe in when we are just resting.