Abdominal breathing, also known as diaphragmatic breathing, is a powerful way to decrease stress by activating the relaxation response in your nervous system. This technique is a simple and quick way to place your body and mind in a state of relaxation and over time may reduce tension and fatigue. Initially, practise this technique three times daily for 10-15 minutes before meals, then after one month you can reduce it to just one to two times a day if you like.
Find a comfortable place to sit or lie down, with your feet slightly apart, one hand on your abdomen near the navel, and the other hand on your chest.
Gently exhale the air in your lungs through your mouth, and then inhale slowly through your nose to the count of four, pushing out your abdomen slightly and concentrating on your breath. As you breathe in, imagine warm air flowing all over your body. Hold the breath for a count of at least four, but not more than seven.
Slowly exhale through your mouth while counting to eight. Gently contract your abdominal muscles to completely release the remaining air in the lungs.
Repeat until you feel deeply relaxed for a total of five cycles. You may be able to do only one or two cycles at first.
Once you feel comfortable with your ability to breathe into the abdomen, it is not necessary to use your hands on your abdomen and chest.
Source: The Digestive Health Solution, Benjamin I Brown ND. (Part 3 The Five Steps to Great Gut Health)