The Sherwood Report

Air Travel (Issue No. 17, Part 1)


According to industry estimates, airlines carried 3.6 billion people in 2015–the equivalent of 48% of the world’s population.

While in-flight health-emergencies are rare (1 per 604 flights), flight-related health risks may be under appreciated. In 2000, a British House of Lords select committee report recommended all airlines have a pre-flight health briefing, just as they have a briefing relating to the plane’s equipment. But since they don’t....

Air travel has been linked to health effects ranging from jet lag, airsickness, earaches, headaches, sinus pain, dehydration, discomfort, to the much more serious (cardiovascular conditions including deep vein thrombosis and venous thromboembolism).

20% of passengers will come down with cold symptoms within 5-7 days of flying.

Jet lag’s severity and effects vary widely, from individual to individual. But it generally seems to kick in after crossing 3 time zones, and it can result in fatigue, inertia, lapses in mental attention, and distorted estimates of time, space, and distance.

And some researchers believe that all passengers have a degree of in-flight hypoxia. For healthy people at sea level, blood oxygen saturation levels (SpO2) are around 98%. During flight, planes are set so that, air pressure-wise, it’s as if you were at an altitude of 5,000-6,000 ft (up to 8,000), thus, in flight, most people have about SpO2 at 93-94%. (At 8,000, it would be 90% within 30 min.) That isn’t considered a serious risk in the air, but, on the other hand, the researchers pointed out that if you were in a hospital with that, you’d be put on oxygen.

Even without the mental impairment from severe hypoxia (e.g., palpitations, dizziness), some scientists have found that 5,000 ft has been enough for a 1-2% deficit in some cognitive skills. 


In a 2007 study of flight attendants, their ability to concentrate was 14% lower on a flight home, than it was on an outbound flight.

Estimates are that somewhere between 10 and 40% of the general population has a fear of flying.

Studies of glider pilots and passengers found that, after 30-40 minutes of sitting in an airplane, we start large fidgeting– intended to relieve localized discomfort and pressure.

After a one-hour flight experiment, Brazilian air force pilots’ hydration dropped 6.1%, and was related to cardiac changes.

A 2017 PNAS study of MLB games found that jet lag can temporarily cancel out home field advantage for home teams traveling after a Western road trip. 

Ashley Merryman