根據2005年5月出版的《麻醉學》的研究：超過一半的乘坐飛機旅行的乘客血氧飽和度下降到一定水平，在該水平許多住院患者必須接受額外的氧氣。

在該項研究中，涉及了84位從1歲~78歲的旅客，由麻醉醫生檢測了他們在地面和飛機巡航高度的血氧飽和度。在地面為97%而在空中下降為93%。

皇家集團醫院麻醉專家注冊主任Susan Humphreys醫生指出：“我們相信這種下降的氧氣水平，合并諸如脫水、活動減少以及濕度較低，能夠導致飛行途中和飛行結束后疾病的發生。”

55位乘客長途飛行超過2小時，其余29位乘客是短途飛行。從這兩組人群中得到的檢測結果類似。這些受試者都沒有嚴重的心肺疾病。

Humphreys醫生說：“54%的受試者血氧在最大高度都小于94%，早期研究結果提示：如果住院患者處于這個水平，有1/3的醫生會讓患者吸氧。”
 
Oxygen Too Low for Some Air Passengers
 
More than half of people traveling on airplanes have their oxygen saturation drop to a level at which many hospital patients would be prescribed extra oxygen, according to a study published in the May 2005 issue of Anesthesia.

In the study, 84 passengers, aged one to 78, had their oxygen saturation levels measured by anesthesiologists on the ground and at cruising altitude. 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.