1. Initiation of exercise
Exercise leads to an increase in the activity of the sympathetic nervous system and carbon dioxide production, which elevates the blood's acidity and increases the breathing rate.
2. Moderate exercise
When there is an increase in oxygen consumption and carbon dioxide production, the lung's need for gas exchange increases.
3. Abrupt ascent into high altitudes
The primary lung response to altitude is hyperventilation, and with an increased heart rate, both aim to provide enough oxygen to tissues.
4. Paralysis of phrenic nerve
Phrenic nerve paralysis causes impairment of the diaphragm which results in shallow breathing and respiratory problems.
5. Severe anemia
Anemia reduces the blood's capacity to transport oxygen; as a result, lungs overcompensate to bring in more oxygen which eventually leads to breathing difficulties
10. Advanced pregnancy
In advanced pregnancy, the diaphragm may get compressed by the expanding uterus, which decreases lung capacity. It takes effort to maintain oxygen intake and higher respiratory rates.