2. Moderate exercise: similar with the initiation of exercise the body requires more oxygen to keep the muscles moving because muscles work harder
3. Abrupt ascent into high altitudes: There is less oxygen and air at higher altitudes, and more pressure, thus the lungs need to work harder to let in more oxygen because it is not as abundant
4. Paralysis of phrenic nerve: it can mean a paralyzed diaphragm which makes it hard to breath as the diaphragm does not move up and down as efficiently and inhale and exhale air.
5. Severe anemia: the lungs overcompensate to bring in more oxygen because low levels of hemoglobin which don’t allow as much oxygen to be brought around the body.
10. Advanced pregnancy: lungs need to overcompensate because oxygen need to travel to the placenta as well and the baby could not allow the diaphragm to move as much, and allow the lungs to move or expand as wide.