Hypoxia While Flying

By Nancy Steinbach

This is the VOA Special English SCIENCE REPORT.

Airline industry officials say as many as one-hundred people a year die from medical problems suffered while travelling on airplanes.

One of these problems is hypoxia, a lack of oxygen to the brain. Medical experts say the body begins losing oxygen minutes after a plane leaves the ground. The air pressure inside an airplane in flight is lower than at sea level. This makes it more difficult for the body to effectively use the same amount of oxygen as it would on the ground. Fewer oxygen molecules cross the tissues in the lungs and reach the bloodstream.

The result is a five to twenty percent drop in the amount of oxygen in the blood. This reduces the amount of oxygen that reaches the organs of the body.

A headache is one result of this lack of oxygen to the brain. When this happens, the heart tries to fix the situation by beating harder and faster. This can make the person feel tired.

These signs of hypoxia are not dangerous in a healthy person. But a drop in oxygen level can cause a health emergency in people with lung or heart problems. They might lose consciousness or even suffer a heart attack.

Medical experts say another cause of hypoxia in flight is the use of alcohol or cigarettes before getting on the plane. Drinking alcohol reduces the body's ability to use oxygen effectively. Cigarette smoking damages the tissues in the lungs where oxygen is exchanged. Experts say people should not drink alcohol or smoke cigarettes either before or during a flight. The result could be chest pain or a heart attack.

A health study completed last year showed that having a meal before flying can prevent such problems. Makoto Matsumura of the Saitama Medical School in Japan reported the findings at an American Heart Association meeting.

The study involved twelve people in a pressure-controlled room. Researchers produced conditions similar to those on an airplane in flight. They tested the peoples' health before and after eating and drinking. They found that eating a meal increased oxygen levels in the brain by forty-eight percent. It increased oxygen in other organs by twenty-one percent.

Medical experts say flying is generally safe. But they say people with heart, lung or blood problems should talk to their doctors before traveling on an airplane.

This VOA Special English SCIENCE REPORT was written by Nancy Steinbach.