Science
How does breathing work?
Breathing works by moving air in and out of your lungs so your body can take in oxygen and get rid of carbon dioxide. A muscle below the lungs, the diaphragm, contracts to pull air in and relaxes to push it out.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how breathing works.
Step by step
- 1The diaphragm contracts and flattens, expanding the chest to draw air in.
- 2Air fills tiny sacs (alveoli) in the lungs.
- 3Oxygen passes into the blood; carbon dioxide passes out.
- 4Relaxing the diaphragm pushes the used air back out.
- 5Your brainstem controls the rhythm automatically.
Frequently asked questions
- What happens to air in the lungs?
- In tiny sacs called alveoli, oxygen crosses into the blood and carbon dioxide moves out to be exhaled — a swap called gas exchange.
- What muscle controls breathing?
- Mainly the diaphragm, a dome of muscle below the lungs; it contracts to pull air in and relaxes to let it out, helped by rib muscles.
- Why do you breathe faster when exercising?
- Working muscles use more oxygen and make more carbon dioxide, so your body speeds breathing to supply and clear them faster.