1. Maintain your healthy lifestyle before you fly
General healthy habits keep your immune system strong, Foreman says. That means getting enough rest, exercising and eating a healthy diet before you take off can help keep you well on a flight. She also recommends taking a daily multivitamin, a vitamin C tablet and a preventative dose of a ginseng product such as COLD-FX prior to travelling. "Research shows that North American ginseng root, which COLD-FX contains, can help prevent colds and flu," Foreman says. But always check with your doctor before taking any supplements.
Seniors should also consider getting a flu shot to help protect them, especially during the winter months.
2. Stay hydrated
Researchers believe we're more susceptible to catching a cold after flying because of the low humidity levels of flight cabins. "Our mucous membranes, including the nose and mouth, are more protective when moist. When they're dry, it's easier for a virus to latch on," Foreman explains.
She recommends buying a large bottle of water once you're through security, and avoiding alcoholic and caffeinated beverages in flight. Also, consider using an over-the-counter saline nasal spray, gel or balm to lubricate your nasal passages.
3. Keep all prescriptions in your carry-on luggage
It's important to always have necessary medications on hand in case you experience an in-flight emergency. A little-known risk to leaving your prescription meds in your checked bags is that the bottom of the plane -- where luggage is stored -- tends to freeze, which may alter the efficacy of some medications. Foreman stresses that it’s important to carry all drugs in their original, pharmacy-labelled packaging, especially if you're crossing any international borders.
4. Take precautions against deep-vein thrombosis (DVT)
"Anyone at risk for clotting -- including smokers, people over 40 and women over 35 on the birth control pill or hormone replacement therapy -- should ask their doctor about flying," Foreman says.
The odds of developing DVT during travel are small, though the condition is more likely to occur on longer flights. If you're at particular risk for DVT, ask your doctor if it would be safe and beneficial for you to take a low-dose aspirin before flying in order to prevent blood clots.
Wearing a pair of compression stockings may also help improve circulation in-flight.
While in the air, remember to flex your feet regularly and walk around the cabin on an hourly basis. Notify a flight attendant immediately if you feel shortness of breath, chest pain or leg pain, or if you develop a raised, reddened hard spot on your leg.
5. Avoid contamination
Airplane surfaces are virtual Petri dishes for bacteria. Use an alcohol-based hand sanitizer after touching any common surfaces and to wipe down your tray. Avoid touching your hands to your eyes, nose or mouth and pack a travel-size bottle of mouthwash to use on the flight.
"Rinsing with it once or twice during longer flights will help disinfect the mouth," Foreman says. And if you find yourself sitting next to a chronic hacker or nose-blower and can't switch seats, consider wearing a disposable facemask. "It's a bit extreme," Foreman admits, "but it's something to think about if you're stuck on a 14-hour flight."