What muscle controls breathing?
General information only. This article explains the basics and is not medical advice. For anything about your own health, talk to a doctor or other qualified professional.
Quick answer
The diaphragm is the main muscle responsible for breathing. It’s a thin, dome-shaped sheet of muscle below the lungs that separates the chest from the abdomen. When it contracts, it flattens and pulls downward, making space for the lungs to fill with air. When it relaxes, it rises again and air flows out.
How one breath works
| Phase | Diaphragm | Ribs | Result |
|---|---|---|---|
| Breathing in | Contracts and flattens | Rib muscles lift ribs up and out | Chest gets bigger, pressure in lungs drops, air rushes in |
| Breathing out | Relaxes and domes upward | Ribs fall back | Chest gets smaller, air flows out |
This pressure change follows a basic rule of gases; see Boyle’s law.
At rest, breathing out is mostly passive: the diaphragm simply relaxes. During exercise, abdominal muscles help push air out faster.
Helper muscles
| Muscle | Role |
|---|---|
| Intercostals | Muscles between the ribs that lift and lower the rib cage |
| Neck and shoulder muscles | Help during heavy breathing |
| Abdominal muscles | Help force air out when coughing or exercising |
Automatic and voluntary
You don’t have to think about breathing: the brainstem controls it automatically, adjusting your rate based on carbon dioxide levels in your blood. But you can also take control, holding your breath or breathing slowly, unlike most automatic body functions. Slow breathing is used in relaxation practices; see how to meditate for beginners.
Hiccups
Hiccups happen when the diaphragm suddenly spasms, pulling in air that’s stopped by the vocal cords snapping shut, which makes the “hic” sound. The vocal cords sit in the voice box. Most hiccups go away on their own within minutes.
Diaphragm facts
- You breathe roughly 20,000 times a day.
- The diaphragm has openings that let the esophagus and major blood vessels pass through.
- Singers and wind players train to control their diaphragm for steady airflow.
Some unconscious body functions are controlled by a different system; see which part of the nervous system controls involuntary functions.
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