Diaphragmatic breathing and hiatal hernia

The diaphragm is part of the antireflux barrier

Diaphragmatic breathing has been studied as an adjunct in the treatment of gastroesophageal reflux. It is also used in people with hiatal hernia, although research specifically involving this group is still limited.

To understand its potential effects, first consider the anatomy. The diaphragm has functions beyond breathing. Part of its musculature surrounds the esophageal hiatus and contributes to closure at the junction between the esophagus and the stomach. Much of the research on breathing and reflux focuses on this mechanism.

Before reaching the stomach, the esophagus passes through the diaphragm via the esophageal hiatus.

Two distinct muscular structures are involved in this region. The lower esophageal sphincter is composed of smooth muscle and maintains tonic closure pressure at the junction between the esophagus and stomach. Around it, the crural diaphragm forms a second muscular barrier. It contracts during inspiration and responds to changes in abdominal pressure.

The angle of His, the phrenoesophageal ligament and the segment of the esophagus normally located below the diaphragm complete this antireflux mechanism.

In a sliding hiatal hernia, the gastroesophageal junction moves partly above the diaphragm. The normal alignment between the sphincter and the diaphragmatic component is disrupted, and the antireflux barrier may become less effective.

This is one reason hiatal hernia is frequently associated with gastroesophageal reflux. Many small hernias, however, cause no symptoms and are found incidentally during investigations performed for other reasons.

Abdominal pressure

Pressure conditions differ between the thorax and abdomen. During inspiration, pressure inside the thorax falls while the downward movement of the diaphragm increases pressure within the abdomen.

This difference is part of normal respiratory mechanics. When the gastroesophageal barrier is less competent, increases in abdominal pressure can make it easier for stomach contents to move into the esophagus.

Abdominal obesity and pregnancy are two of the best-studied factors. Persistent coughing, constipation, repeated straining and Valsalva maneuvers also increase intra-abdominal pressure, although the evidence linking each of these directly to hiatal hernia is not equally strong.

External compression can also produce measurable changes. In one study of healthy volunteers, a tight waist belt displaced the gastroesophageal junction upwards within the hiatus. In patients with esophagitis or Barrett’s esophagus, abdominal compression increased intragastric pressure and slowed clearance of acid from the esophagus.

From a physiological standpoint, it is reasonable to avoid tight clothing around the abdomen, particularly after meals, limit heavy straining on a full stomach and, for people who are overweight, lose weight. Weight reduction, when indicated, remains one of the lifestyle measures with the strongest support in reflux guidelines.

Clinical evidence for diaphragmatic breathing

Diaphragmatic breathing does not lower abdominal pressure. As the diaphragm descends during inspiration, intra-abdominal pressure rises.

The effects reported in reflux studies appear to be related mainly to the crural diaphragm, the muscular portion surrounding the esophageal hiatus that contributes to closure of the gastroesophageal junction.

In a 2021 trial, patients with confirmed reflux were assessed using high-resolution impedance manometry after a meal. During diaphragmatic breathing, pressure at the gastroesophageal junction increased from 23.1 to 42.2 mmHg. The investigators also recorded fewer reflux episodes and lower acid exposure during the following two hours.

Another study using inspiratory muscle training found an increase in resting pressure at the gastroesophageal junction, fewer transient lower esophageal sphincter relaxations and reductions in heartburn and regurgitation. The study included only a small number of participants, which limits interpretation of the findings.

A meta-analysis published in 2026 brought together ten randomized trials involving 476 participants. Pooled results showed a reduction in symptom scores, but the findings varied considerably between studies and there was no significant improvement in quality of life.

A further limitation concerns the applicability of these findings to hiatal hernia. Much of the research has been carried out in people with gastroesophageal reflux rather than in cohorts selected specifically for hiatal hernia. Some studies included small hiatal hernias, while others excluded larger ones or set an upper limit of two centimeters.

The available studies suggest a functional effect on the antireflux barrier. They do not show that breathing exercises reduce the size of a hernia or permanently change the position of the stomach.

Posture and thoracic mobility

The relationship between posture and reflux has been studied mainly in older adults with spinal changes.

Some studies have found an association between marked kyphosis and the size of a hiatal hernia. Changes in sagittal alignment and lower back extensor strength have also been associated with more reflux symptoms.

These studies show associations. They do not establish that a particular posture causes a hiatal hernia. Nor has it been shown that improving thoracic mobility reduces the size of the hernia or changes esophageal acid exposure.

From a respiratory physiotherapy perspective, improving rib-cage mobility can make thoracic expansion easier and allow respiratory movement to be distributed more evenly across the rib cage. The aim is to improve respiratory mechanics, not to alter the anatomy of the hiatus.

The nervous system and symptom perception

The vagus nerve contributes to esophageal and gastric motility, gastric accommodation and several digestive reflexes. It also carries sensory information from the gastrointestinal tract to the brain.

This matters clinically because symptom intensity does not always match the amount of reflux recorded during testing. In some people, esophageal hypersensitivity or a heightened response to internal sensations can make symptoms feel intense despite relatively limited acid exposure.

Slow breathing changes several cardiovascular measures influenced by respiration and autonomic activity. On its own, this does not show that slow breathing “stimulates the vagus nerve” as a treatment for reflux or hiatal hernia.

The relationship involves several processes, including the regulation of digestive motility and the way the nervous system processes sensations such as fullness, pressure, burning and pain.

The microbiome and reflux

Research on probiotics and reflux remains limited.

A 2020 systematic review examined thirteen prospective studies involving 951 participants. Several reported improvements in digestive symptoms, but there were substantial differences in the probiotic strains, doses, treatment duration and methodological quality of the studies.

Current evidence is not sufficient to establish a specific probiotic approach for gastroesophageal reflux. There is also no evidence that probiotics change a hiatal hernia.

After meals

Reflux is more common after eating because the stomach is fuller and pressure at the gastroesophageal junction increases.

Lying down soon after dinner makes it easier for stomach contents to reach the esophagus. Reflux guidelines therefore recommend leaving several hours between the evening meal and going to bed, particularly for people with nighttime symptoms.

Sleeping position also makes a difference. Studies have recorded lower esophageal acid exposure when lying on the left side compared with the right. Elevating the head of the bed can also help when symptoms occur mainly at night.

Meal volume also influences reflux. Large meals produce greater gastric distension and can make reflux more likely. People prone to reflux often tolerate smaller portions better, particularly in the evening.

A gentle walk after eating keeps the body upright without placing substantial strain on the abdomen. Specific evidence for walking as a treatment for reflux is limited. In the study most often cited in support of this advice, walking formed part of the protocol, but the clearer effect was associated with chewing gum.

Strenuous exercise, by contrast, may promote reflux. Running can increase esophageal acid exposure, while activities involving Valsalva maneuvers or high abdominal pressure are poorly suited to the period immediately after a meal.

When medical assessment is needed

Many small hiatal hernias do not require specific treatment. Some cause no symptoms at all.

Progressive difficulty swallowing, gastrointestinal bleeding, black stools, anemia, persistent vomiting or unexplained weight loss require medical assessment.

New chest pain should not automatically be attributed to reflux.

Large and paraesophageal hernias differ clinically from small sliding hernias and may require surgical treatment in certain circumstances.

Diaphragmatic breathing in practice

Diaphragmatic breathing can increase the contribution of the crural diaphragm to the antireflux barrier. Some studies have recorded fewer reflux episodes after meals together with higher pressure at the gastroesophageal junction.

When it is well tolerated, it can be used as part of reflux management alongside control of abdominal pressure, appropriate habits after meals and thoracic mobility work.