Schedule some tea time. Begin drinking “20 ounces of black tea daily” a week before your trip. According to the National Academy of Sciences, it “causes the body to secrete two to four times more interferon,” strengthening the immune system.
Eat and drink properly. “Hydration is key,” as is figuring out the “right preflight meal.” Before flying, “eat a protein-packed meal,” such as a burger, to avoid nausea. Drink “64 to 80 ounces of water” per day. “Limit alcohol, caffeine, and other diuretics,” and avoid in-flight coffee and tea, which are usually made with a jet’s tank water.
Talk to your doc. An airplane’s reduced air pressure and lower oxygen levels can result in headaches, nausea, and dizziness. Before departing, consider asking your physician for acetazolamide, a drug that helps your body metabolize more oxygen. Taking “250 milligrams twice a day after traveling can relieve those symptoms.
Source: Men’s Health