The diaphragm is a large, dome-shaped muscle located at the base of the lungs.
Diaphragmatic breathing (also called “belly breathing” or “abdominal breathing”) is a technique in which you consciously engage the diaphragm to take slower, deeper breaths, thereby increasing lung efficiency and reducing reliance on accessory muscles of breathing.
When you inhale via the diaphragm, the muscle contracts and moves downward, allowing the lungs to expand more fully. On exhalation, the diaphragm relaxes and moves upward. This pattern supports better ventilation and potentially more effective gas exchange (oxygen in, carbon dioxide out).
The diaphragm is a dome-shaped sheet of skeletal muscle located below the lungs, separating the thoracic cavity (which houses the heart and lungs) from the abdominal cavity. It is the primary muscle of respiration and plays a crucial role in the breathing process.
During inhalation, the diaphragm contracts and moves downward, increasing the volume of the thoracic cavity and reducing internal pressure. This pressure change allows air to flow into the lungs. During exhalation, the diaphragm relaxes and moves upward, decreasing thoracic volume and forcing air out of the lungs.
In addition to the diaphragm, other primary muscles of breathing include the external intercostal muscles, which assist by elevating the ribs and expanding the chest cavity during inspiration.
When the body requires increased respiratory effort, such as during exercise or respiratory distress, accessory muscles are recruited. These include the sternocleidomastoid and scalene muscles in the neck, which help lift the rib cage, and the pectoralis minor and serratus anterior in the chest.
Abdominal muscles, such as the rectus abdominis and internal obliques, assist with active exhalation by pushing the diaphragm upward and forcing air out more rapidly. Together, these muscle groups maintain efficient breathing mechanics and ensure adequate oxygen delivery throughout the body. 3
Clinical review evidence suggests diaphragmatic breathing may improve exercise capacity and respiratory function in conditions such as chronic obstructive pulmonary disease (COPD). It also prompts more efficient ventilation mechanics, with improved diaphragm excursion and decreased reliance on accessory muscles.
By activating the diaphragm and encouraging slower, deeper breathing, diaphragmatic breathing may stimulate the parasympathetic (rest-and-digest) nervous system, helping reduce heart rate, blood pressure and stress biomarkers.
A study found that diaphragmatic breathing resulted in lower salivary cortisol (stress hormone) and improved attention after eight weeks of training. 2
While evidence is still emerging, diaphragmatic breathing has been studied in various health settings:
Hypertension and pre-hypertension: diaphragmatic deep breathing showed benefit in improving autonomic dysfunction. 4
Gastroesophageal reflux disease (GERD): A 2024 study found significant improvement in GERD symptoms with diaphragmatic breathing. 5
Stress-related and mental health endpoints: Meta-analysis of breathwork (including diaphragmatic breathing) demonstrated reductions in anxiety and depressive symptoms. 6
Note: These practices may help support health but are not a substitute for medical management in serious respiratory or cardiovascular disease.
Here is a step-by-step method suitable for beginners:
Start lying down, on your back with your knees bent and feet flat on the surface (this reduces demand on the diaphragm).
Place one hand on your upper chest and the other hand on your abdomen (just below the rib-cage).
Inhale slowly through your nose, allowing your abdomen to rise while your chest remains relatively still. You should feel the hand on your belly rising more than the one on your chest.
Exhale slowly through your mouth (or nose) while the abdomen falls, the chest remains still.
Aim for a slow pace - for example, inhale 4-5 seconds, exhale 4-5 seconds. Beginners may practise 5-10 minutes, 1-3 times daily.
As you become comfortable, practise in a seated position, then in a standing position.
Ensure you are relaxed, no rush, avoid forcing the breathing. If you feel light-headed or dizzy, slow down and resume normal breathing.
Key points to remember:
Focus on expanding the belly (not the chest) during inhalation.
Keep shoulders and upper chest relaxed.
Use the diaphragm muscle actively (feel it engage).
Practise consistently for meaningful benefit.
For people with lung diseases (e.g., COPD, asthma), or significant cardiovascular problems, diaphragmatic breathing should be introduced under guidance, as improper technique might increase work of breathing or cause discomfort. 2
During very high demand (e.g., heavy exercise), other breathing patterns may be required; diaphragmatic breathing is especially useful in relaxed or recovery phases. 2
Diaphragmatic breathing is a simple yet potentially powerful technique that emphasises using the diaphragm muscle for slower, deeper, more efficient breathing. It supports better respiratory mechanics, may reduce stress and help in a range of health-related scenarios.
References
Cleveland Clinic. “Diaphragmatic Breathing (Deep Breathing): How to Do It.” Cleveland Clinic, last reviewed August 30, 2023. https://my.clevelandclinic.org/health/articles/9445-diaphragmatic-breathing.
National Center for Biotechnology Information (NCBI). “Physiology, Diaphragm.” StatPearls [Internet], updated October 9, 2023. U.S. National Library of Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC7602530/.
American Lung Association. “How Your Lungs Work.” American Lung Association, accessed November 12, 2025. https://www.lung.org/lung-health-diseases/how-lungs-work.
Yau, Katherine Ka-Yin, and Alice Yuen Loke. “Effects of diaphragmatic deep breathing exercises on prehypertensive or hypertensive adults: A literature review.” Complementary Therapies in Clinical Practice 43 (May 2021): 101315. doi:10.1016/j.ctcp.2021.101315. https://www.sciencedirect.com/science/article/abs/pii/S1744388121000141
Niu, S., et al. “Positive effect of deep diaphragmatic breathing training on gastroesophageal reflux–induced chronic cough: a clinical randomized controlled study.” Respiratory Research (2024). https://respiratory-research.biomedcentral.com/articles/10.1186/s12931-024-02783-5
Fincham, Guy William, Clara Strauss, Jesus Montero-Marin, Kate Cavanagh, et al. “Effect of breathwork on stress and mental health: A meta-analysis of randomised-controlled trials.” Scientific Reports 13 (2023): 432. https://www.nature.com/articles/s41598-022-27247-y
