1. Outsmart Jet Lag
When you land in Europe after an overnight flight, avoid direct sunlight for a few hours: until about 10 a.m. if you're traveling from the East Coast, 1 p.m. if from the West Coast. Then do a quick about-face: Soak up as much sunlight as possible, which will help to suppress the sleep-inducing hormone melatonin.
2. Click Carefully
Studies from the University of Virginia show that the cold-causing rhinovirus can survive in a hotel room for more than 48 hours. Guess where it loves to thrive: the remote. Wash your hands after you click or, even better, wipe it down with an alcohol-based hand sanitizer.
3. How to Avoid a Cold or Flu
Traveling can wear down your immunity, but you can build up your body's defenses by adding the following to your diet: green tea (loaded with antioxidants); Stonyfield Farm yogurt, which has six probiotics; hummus (full of immune-boosting minerals like manganese); and steak and oysters (both are rich in flu-preventing zinc).