1. Initiation of exercise
- As we begin to exercise, proprioceptors sense body position and movement which sends excitatory impulses. These impulses will then stimulate the dorsal respiratory group (DRG) of the medulla which will increase respiration when exercise is initiated.
2. Moderate exercise
- As the muscles contract more, our body consumes more oxygen thus causing an increase in respiratory rate and depth.
3. Abrupt ascent into high altitudes
- Due to the decrease in oxygen in the atmosphere, the lack of oxygen is sensed by peripheral chemoreceptors. This will then cause an increase in breathing rate or hyperventilation.
4. Paralysis of phrenic nerve
- In normal breathing rates, the phrenic nerve receives impulses from the DRG to innervate the diaphragm. In an event that the phrenic nerve experiences paralysis, the patient will not be able to independently breathe as the diaphragm will not be able to contract.
5. Severe anemia
- Anemic hypoxia may occur as there is very limited functioning hemoglobin found in the blood causing a reduce in O2 transport. Because the body is reliant on O2 and CO2 through blood circulation, different parts all throughout the body will experience a decrease in oxygen supply.
6. Advanced pregnancy
- Pregnancy can affect the contraction of the diaphragm as it can obstruct the diaphragms complete descent. It is also important to note that hormonal patterns may cause ventilatory changes.