The pressure difference between the air inside your lungs and the air outside your body is what pulls air in and pushes it out.
How it works:
- Inhaling: When you breathe in, your diaphragm, a large muscle below your lungs, contracts and flattens. This increases the volume of your chest cavity, making the air pressure inside your lungs lower than the air pressure outside. The pressure difference pulls air into your lungs.
- Exhaling: When you breathe out, your diaphragm relaxes and moves back up, decreasing the volume of your chest cavity. This increases the air pressure inside your lungs, making it higher than the air pressure outside. The pressure difference pushes air out of your lungs.
Examples:
- Holding your breath: If you hold your breath, the pressure inside your lungs will eventually equalize with the pressure outside. This is why you can't hold your breath indefinitely.
- Breathing at high altitudes: At higher altitudes, the air pressure is lower. This means that there is less air available to breathe, making it harder to inhale.
