Does the Lack of O2 Harm You During Hyperventilation?

Hyperventilation is rapid shallow overbreathing. The usual cause in susceptible individuals is anxiety or panic attack. Rather than decreasing blood oxygen levels, however, hyperventilation decreases CO2 levels in the bloodstream. It may cause a lack of oxygen supply to brain cells, but its symptoms do not result directly from a lack of oxygen.

Function

• When you breathe too rapidly, you expel CO2 from your lungs more rapidly than normal, so more CO2 is able to diffuse from your blood into your lungs. Ordinarily, some of the CO2 in your bloodstream is present in the form of carbonic acid, a weak acid formed by the reaction of water with dissolved CO2, and bicarbonate, the conjugate base of carbonic acid. As the CO2 concentration decreases, the carbonic acid level decreases, and your blood becomes less acidic---in other words, the pH begins to rise.

Effects

• If the pH of your blood were to rise too far, it would denature important proteins and enzymes and you would die. As the pH rises and the CO2 levels drop, however, the vessels that supply blood to your brain begin to constrict, reducing the supply of oxygen to your neurons. Eventually you pass out and---once you are unconscious---resume normal breathing.

Considerations

• According to eMedicine, death or serious injury from hyperventilation is possible but rare. It's important to bear in mind, however, that hyperventilation can sometimes be caused by serious medical conditions like acute pulmonary embolism, which would warrant immediate emergency treatment.

  As always, none of the above should be interpreted as medical advice. If you or a family member are hyperventilating and are concerned about your condition, the first person from whom you should seek advice is your doctor.