Oxygen Too Low for Some Air Passengers

While ground levels averaged 97%, these levels fell to an average of 93% at high altitude.

"We believe that these falling oxygen levels, together with factors such as dehydration, immobility, and low humidity could contribute to illness during and after flights,” noted Dr. Susan Humphreys, anesthetic specialist registrar of The Royal Group of Hospitals (Belfast, N. Ireland).

Fifty-five passengers were on long flights that lasted for more than two hours, while the remaining 29 were on short flights. The measurements obtained from both groups were similar. None of the subjects had severe cardio-respiratory problems.

"The oxygen levels of 54% of our subjects fell to less than 94% at maximum altitude and an earlier study suggested that a third of physicians would put hospital patients with these levels on extra oxygen,” added Dr. Humphreys.