Hyperventilation is simply a matter
of breathing too rapidly. This condition probably occurs with greater frequency
among student pilots than is generally recognized. It is seldom completely
incapacitating but it does produce one or more of the symptoms, noted later,
that are disturbing if not alarming to the uninformed pilot. Therefore,
it only aggravates the problem by further increasing anxiety, and thus
the breathing rate.
Under conditions of stress and anxiety, a person's body reacts automatically to such stimuli whether the danger be imaginary or real. One of these automatic reactions is a marked increase in breathing rate. This results in a significant decrease in the carbon dioxide content of the blood. Carbon dioxide, of course, is needed to automatically regulate the breathing process. The common symptoms of this condition are dizziness, nausea, hot and cold sensations, tingling of the hands, legs, and feet, sleepiness and finally unconsciousness. Many of these symptoms are also common to hypoxia and some to ordinary airsickness.
It may be that many students who feel dizzy, lightheaded, or grow nauseated on their early flights are suffering from hyperventilation as well as from motion sickness. Both students and instructors should be aware of this possibility. This condition can be relieved by consciously slowing the breathing rate. Talking loudly or breathing into a bag to restore carbon dioxide will effectively slow the breathing rate.