1. Initiation of exercise - Our respiratory rate increases when we begin to exercise because of increased body movement that requires more oxygen.
2. Moderate exercise - When we exercise moderately, our mucles need more oxygen, thus causing increased respiratory rate.
3. Asthma attack - Asthma attack causes the airways to narrow, thus trapping air inside the lungs and making it hard to breathe. Due to this, our body receives less oxygen, so our respiratory rate increases to maintain homeostasis.
4. Abrupt ascent into high altitudes - At higher altitudes, there is less oxygen in the air, so we experience difficulty breathing and increased respiratory rate.
5. Pneumonia - Pneumonia causes difficulty breathing because inflammation causes air sacs to fill with fluid, making gas exchange harder.
6. Paralysis of phrenic nerve - The phrenic nerve controls the contraction and relaxation of the diaphragm; hence paralysis of this nerve will cause shortness of breath.
7. Severe tuberculosis with resulting lung scar tissue - Severe TB causes airway inflammation, thus causing breathing difficulty. The scarred lung caused by severe TB also makes the lungs less efficient.
8. Severe anemia -Red blood cells transport oxygen to various cells of the body, so a person with severe anemia will experience hyperventilation and rapid heartbeat as the body attempts to circulate the red blood cells faster and deliver more oxygen to the body.
9. advanced COPD (chronic obstructive pulmonary disease) -When a person has advanced COPD, mucus obstructs the airways, thus causing respiratory difficulties.
10. Advanced pregnancy - During advanced pregnancy, the uterus presses against the diaphragm, thus causing shortness of breath.