Cold-weather athletes actually suffer from an above-average number of upper-respiratory infections. Research suggests the cause is twofold:
1) a lowered immunity in cold temps, which we all share;
2) a higher volume of air moving in and out of the lungs during exercise, making athletes more susceptible to airborne bacteria and toxins.

But no one wants to stay home when there's a foot of new snow. Just use the following weapons to boost your immune system and save your sick leave for powder days.

GARLIC: Infomercials and grandmas have been touting the benefits of garlic for years, but science has recently revealed how garlic helps—and how you can help it work. A 2003 study conducted at the University of California at Irvine Medical Center showed that garlic juice, thanks to a compound called allicin, has an antibacterial effect. Other studies suggest that garlic inhibits the growth of viruses as well. But allicin is created only when garlic is chopped or sliced (due to an interaction between alliin, a precursor of allicin, and an enzyme). Add fresh chopped garlic to meals, but allow it to sit for a few minutes before cooking. Sniffle defense: The same compounds that make garlic smelly also help break up congestion.

YOGURT: Studies conducted at the University of California at Davis found that yogurt provides a protective barrier against bacteria and makes the immune system stronger. How much stronger? People who ate about a cup of yogurt daily for a year suffered 25 percent fewer colds than non-yogurt eaters. To get the biggest boost, look for labels that read, "contains live and active cultures," and start your yogurt regimen a month before cold season begins.

CAYENNE: Capsaicin, the principal chemical that makes chiles hot, clears your head, nose, and respiratory tract. It also has antiseptic and antimicrobial qualities. For the most powerful effect, you should grind your own cayenne, seeds and all, and add it to your favorite soups and other meals. For a more potent dose, make an infusion by stirring one teaspoon of cayenne powder into one cup of boiling water and letting it stand for ten minutes. Drink a daily glass of water mixed with a teaspoon of the infusion.