...They manage to bring us to our knees (or at least to our beds) every winter.

And even though we may have vanquished their more virulent relatives – polio, smallpox, measles – it seems that rhinoviruses, responsible for that annual inevitability known as the common cold, persist by virtue of their mediocrity.

Although we haven’t found a cure for the common cold, there are a number of ways to boost your immune system to make sure your body’s defenses are up to snuff when cold and flu season arrives.

For athletes, the first thing to consider is exercise. Although exercising can strengthen your immune system, strenuous exercise can actually suppress the immune system for several hours after you work out, increasing your chances of getting sick.

Focus on consuming foods that are high in antioxidants, such as green, yellow and orange vegetables.

Green tea, is another way to get your antioxidants. Thank the polyphenols found in tea leaves, which have a potent antioxidant effect.

Getting enough sleep is universally recommended.

Exercise, eat right and get enough sleep.

Insurance for your Immune System
Glutamine, an amino acid, is also important for athletes. The gastrointestinal (GI) tract is one of the largest centers of the immune system, and glutamine is its primary fuel source. As you increase stress on the body – physical, mental or emotional – GI activity, and therefore demand for glutamine, heightens. If the blood doesn’t contain sufficient levels of glutamine, the body takes it from the musculoskeletal system, which can compromise muscle tissue. The cells of the immune system also use plasma glutamine at a high rate.

Probiotics such as enteric coated Lactobacillus acidophilus is another effective preventative measure and a must if you aren’t taking antibiotics.

Probiotics support the immune system by creating a healthier GI tract. Be careful relying on dietary sources as quality and dosage are unreliable in food.

Of course, when it comes to cold and flu season, you probably first thought of vitamin C and Echinacea.

There’s compelling evidence that vitamin C seems to help prevent the common cold, although it’s less clear whether it prevents the flu. It is thought that vitamin C helps strengthen white blood cell activity, potentially keeping the immune system on the alert and better able to react to viruses. Vitamin C can cause diarrhea if you take too much of the ascorbic acid form. The ascorbate form is preferable and doesn’t do this.

For cold and flu prevention try American ginseng and astragalus. The plant’s polysaccharides have an immunomodulating effect, increasing the body’s ability to produce cytokines, which are critical to immune function.

Preliminary data on astragalus show that it works similarly and is recommended for prevention rather than treatment and should not be taken while you’re sick.

The experts agree on one thing, the über-popular herbal remedy Airborne is not the answer. Despite being developed by an elementary school teacher and receiving a plug from Oprah, Airborne is known for having better marketing than science. There are no clinical studies [supporting its claims].

The absolute best way to avoid getting sick? Avoid sick people, keep your hands away from your eyes and nose, and wash your hands with soap.