Belly breathing: what actually moves when you breathe

What really happens when you breathe in

The diaphragm is a dome-shaped sheet of muscle and tendon between your chest and your belly. It’s the main muscle you breathe in with.¹ When it contracts, it flattens and moves down, a bit like a piston. Your chest cavity gets bigger, your lungs expand, and air flows in.

Because the diaphragm moves down, whatever is in your belly has to make room. Pressure in your abdomen rises, your belly wall moves out, and your lower ribs widen.^{2, 3} That’s why it’s called belly breathing: you see the movement in your belly. The air still goes into your lungs.

1. After you breathe out, the diaphragm arches up under the lungs like a dome.
2. Breathing in: the diaphragm contracts, flattens and moves down. The lungs expand, and air flows into the lungs. Your belly contents make room, so your belly rises.
3. Breathing out: the diaphragm lets go, and everything springs back. At rest, this takes no muscle effort.
4. Posture: lying down, more of the movement comes from the belly (dark); standing, more comes from the chest (light). Both are normal.

Watch again

The distances are smaller than you might think. In an ultrasound study of 410 healthy adults sitting upright, the diaphragm moved just under 2 centimeters (about 3/4 inch) during quiet breathing, and 5 to 7 centimeters (2 to 3 inches) during a deep breath.⁴ Other organs move along: during normal breathing, the liver shifts about 2.5 centimeters (1 inch), and the pelvic floor moves down as you breathe in and back up as you breathe out.^{5, 6}

At rest, breathing out is passive. The diaphragm lets go, and your lungs, rib cage and belly spring back. Your abdominal muscles only join in when you exert yourself.²

Chest breathing isn’t a mistake

You often hear that most people breathe “wrong,” meaning with their chest. Measurements say otherwise: in healthy people, chest and belly always move together. Which one does more depends mostly on your posture. In a study of 37 healthy young adults, lying on their backs, 57 percent of the movement came from the belly on average; standing, only 41 percent did.⁷ Measurements of 81 healthy people back in 1975 found the same pattern: most breathe more with the belly lying down and more with the chest upright.⁸ Women’s rib cages tend to move more than men’s when sitting, because of the shape of their ribs.³

So where does the claim that 90 percent of people breathe wrong come from? In a study of 1,933 athletes, 90.6 percent were rated “dysfunctional.” The rating was based on a visual test done standing up.⁹ But standing, healthy people breathe more with their chest anyway. If your chest rises too, you’re not doing anything wrong.

How to practice belly breathing

It’s easiest to feel the movement lying down, because that’s where your belly moves the most. Later, you can do the same sitting up.

1. Lie comfortably on your back; you can bend your knees. Rest one hand on your belly and one on your chest.
2. Breathe in calmly through your nose. Let your belly lift your hand without pushing it out. Your chest can move too.
3. Breathe out slowly and let your belly sink back on its own.
4. Only breathe as deeply as feels comfortable. Britain’s National Health Service (NHS) puts it the same way: breathe into your belly as far as is comfortable, without forcing it.¹⁰

Your hands are there for feedback, not as a test. How much your chest moves along says nothing about right or wrong.

One minute of belly breathing

Rest a hand on your belly

Breathe along

Belly breathing doesn’t mean deep breathing

A lot of instructions say “breathe deep into your belly.” But deeper isn’t better. In a study of 46 students who breathed six times a minute for ten minutes, the carbon dioxide in their breath dropped noticeably. Those who were asked not to breathe too deeply lost only about half as much, and had fewer symptoms such as dizziness.¹¹ Pushing your belly out doesn’t help either: in a lab study, healthy people moved more air per minute when they deliberately breathed only with the belly or only with the chest, and chest and belly moved less in sync.¹²

How you sit plays a part, too. Slumped, 70 healthy adults did worse on breathing tests that required maximum effort than when sitting upright.¹³ For calm breathing, slouching hasn’t been shown to do harm. Still, sitting upright and relaxed gives your belly room.

What the research shows

There’s surprisingly little good research on belly breathing in healthy adults:

• Eight weeks at an office: 40 employees of an IT company in Beijing practiced diaphragmatic breathing 20 times, with a trainer and a biofeedback device. Afterward they did a bit better on an attention test than the group without training. But the study has weaknesses: the groups weren’t truly randomized, and there was no comparison exercise.¹⁴
• Twenty guided minutes: 60 students felt more relaxed after 20 minutes of deep breathing than after reading magazines. Physically, though, their arousal rose at first and only dropped after that.¹⁵
• Reviews: a 2019 systematic review found only three studies in adults that tested diaphragmatic breathing on its own.¹⁶ A newer review of 48 randomized trials rated just over 2 percent of the results as having a low risk of bias.¹⁷

These studies tested the technique, not the nowa app. Bottom line: belly breathing isn’t a miracle cure. It’s a simple way to breathe calmly and slowly, which is what most breathing exercises are about.

What people say about belly breathing

• “It activates your vagus nerve.” How much your heartbeat varies with your breath depends mainly on how fast and how deeply you breathe.¹⁸ That the belly movement itself adds anything is so far only a hypothesis.¹⁹ More in the article on vagus nerve breathing.
• “It massages your organs.” Your organs do move along; the liver shifts about 2.5 centimeters (1 inch).⁵ Whether that movement does your organs any good has never been studied.
• “It gets you more oxygen.” In healthy people, the blood is already almost fully saturated. Why more air doesn’t mean more oxygen is explained in Does deep breathing give you more oxygen?

Frequently asked questions

What’s the difference between belly breathing and diaphragmatic breathing?

There isn’t one. Both names describe the same movement: the diaphragm moves down as you breathe in, your belly rises, and your lower ribs widen.² Either way, the air goes into your lungs.

Is chest breathing bad?

No. In healthy people, chest and belly always move together, and sitting or standing, the chest does more.^{7, 8} There’s no evidence that most people breathe wrong.

How do I breathe through my diaphragm?

Lie down comfortably, rest a hand on your belly, breathe in calmly through your nose, and let your belly rise instead of pushing it. Breathe out slowly, and only as deeply as feels comfortable.¹⁰ There’s no single right method; no study has compared them.

Should I practice lying down or sitting?

Start lying down: that’s where your belly moves the most, so it’s easier to feel.⁷ Once you know the movement, you can do it sitting too.

Are there any downsides to belly breathing?

No harm has been shown in healthy people. The common mistakes are pushing and breathing too deeply. Then you move more air than you need, and dizziness or tingling can follow.^{12, 11}

How does the diaphragm work with the pelvic floor?

As you breathe in, the diaphragm and the pelvic floor move down together; as you breathe out, they move back up. An MRI study of eight healthy women showed this.⁶

Should I breathe through my nose?

Most instructions have you breathe in through your nose; they differ on breathing out. This hasn’t been studied specifically for belly breathing. Why your nose is handy in everyday life is covered in the article on nasal breathing.