Normal breathing is restricted by stretching of the thoracic walls and lungs, a drop in the H+ and carbon dioxide levels, an increase in oxygen level. Normal breathing is triggered by the relaxing of thoracic walls and the lungs, a decrease in the oxygen levels, and an increase in the carbon dioxide and H+ levels.
The main factors which affect normal breathing are –
- Level of carbon dioxide in the blood
- Level of H+ in the blood
- Stretching in thoracic walls and lungs
- Level of oxygen in the blood
Several other factors too are known to govern normal breathing such as chemicals and emotional state etc.