Have you ever Felt a little achy, lightheaded or even short of breath on a long plane flight? A new study suggests that you might be suffering from a mild form of altitude sickness.
Most modern aircraft are designed to maintain cabin pressures no lower than what is found at 8,000 feet above sea level.
Up until now, such symptoms have always been attributed to jet lag, air contamination, dehydration or being stuck in a cramped seat for hours.
Researchers reported that true altitude sickness — which consists of nausea, vomiting and sleep pattern disturbances — was no more likely to appear in volunteers in simulated airplane cabins with pressures equivalent to 8,000 feet above sea level than it was when the pressure was closer to sea level.
But the studies show that after three hours of exposure to pressures equivalent to 7,000 to 8,000 feet, the simulated fliers were mush more likely than others to report headaches, muscle aches, shortness of breath, light-headedness and impaired coordination.
The groups most likely to suffer with these symptoms were women and younger people, the researchers reported in the New England Journal of Medicine.
“Our findings force us to conclude that maintaining a cabin altitude sub 6,000 feet (equivalent to a barometric pressure of 609 mm Hg or higher) on long-duration commercial flights will reduce the discomfort and unpleasant effects among passengers,” wrote Michael Muhm and colleagues at the Boeing Company, which financed the study.
During the study volunteers were placed, up to 12 people at a time, in a pressure chamber, in coach seats, for up to 20 hours.
In the interests of comparison they were even given airline food. No alcohol was allowed, but they could watch five movies in the pressure chamber to pass the time.
Most modern aircraft are designed to have cabin pressures no lower than the equivalent to what is found at 8,000 feet above sea level, even as the plane ascends much higher.
Flying at lower altitudes makes the cabin pressure higher, but this also make both the planes wear out faster and requires more fuel.
Higher Cost of Lower Pressure
Typically the pressure in a commercial cabin is equivalent to 5,500 to 7,500 feet above sea level and designing an aircraft to withstand a cabin pressure that is equivalent to a lower altitude would also add to the cost of the plane.
Jeanne Yu, Boeing’s director of environmental performance, said the Muhm study prompted the company to set the cabin pressure on its new 787 planes, to be rolled out next week, for 6,000 feet. Showing that commercial airlines are doing what they can to combat this problem.
That is possible in these planes, she said, because the fuselage is made up of a composite structure instead of aluminum.