Over the next few days, millions of Americans will put themselves at risk of infection, dehydration, fatigue, and even blood clots -- by flying on one of the busiest travel days of the year.
"There is no way you can not get sick if you are sitting next to somebody who is sick, or traveling with someone who is sick, whether it is on a plane or a bus or just out in public," says Mary Jean Olsen, a spokesperson for aircraft maker Boeing Corp.
The most serious in-flight condition -- "coach class syndrome" -- happens when passengers get cramped legs from sitting for a long time without moving, "then get off the plane and have a pulmonary embolism, a clot that travels up from the legs and into the lung," said Dr. John McGillen, former chief of internal medicine at Northwest Community Hospital in Chicago. Although this can result from any form of transportation, certain factors associated with air travel such as dehydration, low humidity and pressure, and stress can increase the risk.
To prevent this, "people should get up and walk around the cabin frequently during trips, and move their legs, especially if their flight is longer than six hours," said Andrew Mackler of the Harvard Vanguard Travel Health Department.