Uddiyana Bandha in yoga: what does the diaphragm do?
During Uddiyana Bandha, a yoga exercise, the closed throat and open ribs lower the pressure, which draws the diaphragm upward and hollows the belly: -18 to -44 mmHg were recorded in the stomachs of two people.
The word Uddiyana does not mean the same thing in every school: the lower belly held during postures, or the belly drawn in with empty lungs. This page covers the second, which is the basis of Nauli.
Calm breathing, standing, torso leaning slightly forward, hands on the thighs.
Never breathe in before releasing the belly. Do not force or prolong it: stop if you feel dizzy or have pain.
Schematic drawing, based on descriptions. Mechanism according to Nespor, 1981, discussed below.
What happens at each step?
Six steps, in a single exhale. The pressure values only apply to the step where the belly is held hollow.
| Step | Throat | Diaphragm | What happens |
|---|---|---|---|
| 1. Breathe out fully | Open | Rises | It rises as with every exhale. |
| 2. Close the throat | Closed | Stays high | No more air can go in or out. |
| 3. False inhale | Closed | Drawn upward | The ribs open with no air: pressure drops and the belly hollows. |
| 4. Hold | Closed | At the very top | Stomach at -18 or -44 mmHg on average, depending on the person. |
| 5. Release the belly | Reopens | Comes back down | The ribs lower and the belly returns. |
| 6. Breathe in | Open | Comes back down | Air comes back gently. |
Does the diaphragm work, or is it drawn up?
Authors disagree, and we found no recording of the muscle's activity to settle it.
| Author | What they describe |
|---|---|
| Kuvalayananda, 1924 | After the exhale, the back muscles pull the spine upward and the rectus muscles push the belly up and in. |
| Nespor, 1981 | The muscles between the ribs perform a false inhale, with the throat closed. The relaxed diaphragm is drawn up and the abdominal wall stays passive. Our animation follows this description. |
| Dallaghan, 2019 | The diaphragm is active, “reverse contracted.” For this author, the technique is a “pre-nauli,” and the word uddiyana refers to the lower belly. |
What do the measurements show?
- Pressure: in the stomach, on average -18 mmHg (2.3 kPa) in a slender female student and -44 mmHg (5.9 kPa) in a professional dancer. Nespor is reporting his own experiment here, published in a Czech journal we have not read.
- X-rays: in 1924, the colon was studied with an opaque meal, in a young man who had practiced for six months. These images are partial: he was lying down and relaxed one side during one X-ray.
- Heart: in a 2024 trial, one session changed heart rate variability in people with high blood pressure aged 40 to 60, with no evidence of a lasting effect.
- Hypothesis: massage of the organs and help with digestion, claimed with no measurement presented.
Frequently asked questions
Are Uddiyana and the stomach vacuum the same?
Both draw the belly in with empty lungs and look alike. The bodybuilding stomach vacuum is often described as a contraction of the transverse muscle, while Nespor describes a passive, drawn-in wall for Uddiyana. We found no measurement comparing them.
Why should you not breathe in too soon?
If air comes in while the belly is still drawn in, it rushes into a chest under negative pressure. Yoga schools therefore ask you to release first. This advice comes from practice, not from a study.
What is the effect on the heart?
A 2024 trial reports, after one session, an interval between two heartbeats going from 719 to 789 ms and an LF/HF ratio going from 1.62 to 1.32. The article states 60 people in its abstract and 80 in its methods. It says nothing about the long term or about the medications people were taking. The 1924 article, for its part, warns of high pressure on the heart.
Who should avoid Uddiyana Bandha?
People with heart disease, according to the 1924 article, which also calls for an empty stomach and no more than three attempts a day for beginners. Yoga schools add pregnancy, menstruation, recent abdominal surgery, hernia and ulcers. This advice does not come from clinical studies: with high blood pressure, ask a doctor.
See also
Nauli The muscles of breathing Breath-holding
Sources
- Nespor K. Uddiyana Bandha. Yoga (Bihar School of Yoga). June 1981. Article text
- Kuvalayananda S. What is Uddiyana? and X-ray experiments on Uddiyana. Yoga-Mimansa. 1924;1(1):9-24. Full issue (PDF)
- Dallaghan P. Diaphragm raised (pre-nauli), lower abdomen engaged (uddiyana zone), pelvic floor managed (mula). Samahita Retreat, March 3, 2019. Article
- Govindasamy K et al. Immediate Effect of Uddiyana Bandha on Heart Rate Variability in Patients with Hypertension: A Randomised Controlled Study. Ann Neurosci. 2024. PMC11638923
True or false?
During Uddiyana Bandha, pressure in the stomach falls below air pressure.
True. It reached on average -18 mmHg in a slender female student and -44 mmHg in a professional dancer (Nespor, 1981).
You hollow the belly by breathing in.
False. The technique starts after a full exhale, with the throat closed: the ribs open, but no air comes in (Nespor, 1981).
All authors agree on the role of the diaphragm.
False. Nespor describes it as relaxed and drawn up, Dallaghan as active. We found no recording of the muscle to settle it.
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Metabolive. "Uddiyana Bandha in yoga: what does the diaphragm do?" Updated October 31, 2026. https://metabolive.com/en/effort-stress/uddiyana-bandha.