A dropping level of CO2 from hyper ventialtion also disturbs the acid-base balance in the blood which in itself can cause dizziness, impaired mental function an

A dropping level of CO2 from hyper ventialtion also disturbs the acid-base balance in the blood which in itself can cause dizziness, impaired mental function and tingling fingers as if you have a lack of oxygen. At high altitude it's easy to mistake this for hypoxia (due to loss of pressure), because the feeling and visible symptoms can be very similar. The distinguishing symptom is seeing blue lips/fingers, that doesn't happen with hyperventilation. But if you've taken hypoxia that far you're in a lot of trouble. Recommended approach for flight crews is to not bother figuring out whether it's hypoxia or hyperventilation but instead for everyone to put on oxygen masks, verify each other's masks and focus on breathing normally. It will fix both issues and ensures that the rest of the crew is fine in case it was hypoxia.