News & Advice

How Your Plane Can Make You Sick

Plus, how those cabin germs actually spread.
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Illustration by Brown Bird Design

Dehydration. An achy, flu-like feeling; a splitting headache and ringing ears, nausea: just being on a plane can lead to some unpleasant side-effects—and often, a cold. But what is it about flying that makes you feel lousy?

The Fumes

The occasional passenger will leave a flight with more than the usual post-flight hangover—so much so that the Federal Aviation Administration, we’ve learned, is likely to soon issue a safety alert on fumes or smoke that can seep into the interior of the plane.

The FAA declined to comment for the record. But the agency’s possible move follows a series of reports of severe headaches and nausea after passengers and crew reported a gasoline-like smell, evidence that they were experiencing a “fume event"—meaning that some vapors from the jet fuel pumping into the jet engines was actually seeping into the cabin atmosphere due to a mechanical glitch. According to several flight attendant unions, it’s been happening often enough that the groups have been pushing for congressional passage of a “Cabin Air Safety Act” that would slap tough regulations on the airlines, requiring them to better monitor and respond to “toxic” fume events.

Pilots and flight attendant groups supporting the bill have been complaining about fumes for years. But until now, they haven’t had much success getting regulations to require the airlines to report all such events. If the FAA issues its proposed safety alert, the flying public will at least be more informed (alerts are typically issued for critical safety matters—like overheating lithium batteries—and they often come with a set deadline for fixing the problem).

Boeing and Airbus, for their part, say that the air in their planes is safe; according to the industry trade group Airlines for America “frequent studies over the years have consistently concluded that cabin air meets or exceeds health and safety standards.” The groups also insist that fume events are rare, and that the level of toxins is so low as to be negligible.

The Air

Cabin air is as dry as a desert and as thin as the atmosphere at an elevation of 8,000 feet above sea level. There’s a good reason for this: Most planes flying are made of aluminum, and to prevent metal fatigue, the air needs to be dry and to be pressurized at a high altitude. The newest planes from Boeing and Airbus—the 787 Dreamliner and A350—are made of more flexible composite materials and can be pressurized at a more tolerable level of 6,000 feet, plus, airlines can pump more humidity into the cabin. But the majority of passengers still have to endure the side effects of the old, all-metal airplanes: you'll feel dehydrated, and your body will swell slightly.

That thin air up at cruising altitude can have an effect on your health, too. Medical expert (and former Traveler columnist) Richard Dawood says that passengers, especially on long flights, are “effectively suffering from the effects of acute mountain sickness." This is more noticeable aboard ultra-long flights where being suspended at a high altitude can bring on sort of light-headed feeling.

The Spread of Germs

Cabin air is recirculated; to the average flier that raises the prospect of catching a cold, or worse, from a sick fellow passenger. Though cabin air is filtered through a system similar to what’s used in hospitals, it won’t catch everything. Recently, researchers at Emory University tracked 1,540 passengers and 41 crewmembers to see how germs spread in-flight, and what they found about the spread of colds and infectious diseases was staggering: the study showed that a sick cabin crew member was likely to infect an average of 4.6 passengers per flight, and that those seated in the middle and aisle seats, due to their proximity to crew, were at the greatest risk. (Still, cabin crew are more likely to infect each other, due to their time in the galley.) Seated less than one row away from a coughing, sneezing person? If you're among that sick passenger's 11 nearest neighbors, you have more than an 80 percent chance of infection, reports Wired.

The Sun

Germs aside, there's another risk factor in those super-long flights: exposure to UV rays and cosmic radiation—that is, radiation from the sun and other stars. That's because the earth's protective shield is weaker above 30,000 feet, and exposure is even higher for flights over the North Pole and during solar flares. The actual per-person dose can vary, but according to research from NASA, a typical Chicago-Beijing flight over the pole would deliver the equivalent of two chest X-rays. Flight crews, of course, fly the most and incur the highest risk; research indicates they have twice the rate of melanoma than the general population. (In fact, the FAA has classified pilots as "occupational radiation workers.") That has led some international airlines to issue guidance to pilots to monitor radiation activity and to descend to lower altitudes when levels rise. However, the risk to the majority of travelers is slight, medical experts say, and they point out that we're exposure to radiation routinely during our daily lives.

What You Can Do

Ultimately, however, there’s not a lot you can do to avoid any of this, and there have been no studies to suggest that travelers—even frequent fliers—are any more at risk of serious illness than their stay-at-home counterparts. But, doctors say, you can at least improve the odds of arriving in better shape by following some basic advice. Avoid caffeine and alcohol (though some of us would prefer to ignore that advice and take the consequences), and take along saline spray to ward off the dreaded ear squeeze we feel on descent. Finally, follow this advice from travel health pros: take along a travel-size bottle of hand sanitizer, and generously spread it on your armrest, tray table, and any other surface you can find. You may get some strange looks, but you may feel better when you land.