2. The common way for adults to breathe is chest breathing. Chest breathing is dominated by rib and sternum movements, and the breast diameter increases before and after inhalation. Because when breathing, air directly enters the lungs, so the chest will expand and the abdomen will remain flat. Compared with abdominal breathing, chest breathing is shallow breathing, and air is sucked into the upper part of the lungs.

3. Abdominal breathing is mainly diaphragmatic movement. During abdominal breathing, the diaphragm will drop and the abdominal pressure will increase. It feels like air directly enters the abdomen. At this time, if you put your hand on the navel, you will feel your hand slightly lifted up and down. In fact, the air does not enter the abdomen, but the movement of the diaphragm drives the movement of the abdomen, and the air is sucked into the bottom of the lung, which is helpful for full gas exchange.

4. Abdominal breathing can expand vital capacity, maximize the chest, make the lung wall and alveoli in the lower part of the lung expand and contract, let more oxygen enter the lung, and slow down the heart rate. Therefore, the pranayama of free diving is mainly abdominal breathing.