Hyperventilation is the excessive ventilation of the lungs: in other words, rapid and often shallow breathing beyond what the body requires to maintain normal gas quantities in the bloodstream.
There are a number of reasons why a person might hyperventilate and those can generally be divided into two camps: psychological and physiological conditions.
As a symptom of more serious ailments it can result from renal (kidney) failure, pulmonary oedema (fluid in the lungs), drug overdose, a fever and, more frequently, asthma. The most common causes of hyperventilation, however, are psychological – a result of a stressful situation or a panic attack.
Contrary to popular belief, the effect of this kind of breathing isn’t to increase oxygen intake, but to lower the volume of carbon dioxide in the blood by exhaling more than the amount produced by the body.
The well-known treatment of breathing into a paper bag (neither advised nor taught) was invented by a US army medic in 1951. Although this method – known as rebreathing – often works, today’s medical experts say it is dangerous and should be avoided.