Run away from cold and flu season.

Runners enjoy the benefits of enhanced health including a tip-top immune system, but only up to a point. Training too hard and too often can leave you more vulnerable to colds and flu. As in all things, moderation is best. But the point at which exercise can tip the balance from good for you to bad may be far closer to what you would consider moderate training than you might think. In recent research, 33 healthy but sedentary young men were randomly assigned to three exercise regimens--exercise at 70% to 85% of maximum heart rate three times a week; exercise at the same intensity but four to five times a week; and non-exercising controls. The less frequent exercisers showed improvements in certain markers of immune function and the more frequent exercisers suffered reductions. While the research begs many questions, studies have shown over and over again that when it comes to your body's immune system and exercise, less is more.

What to Do if You Get Sick

If you feel off color and unwell in the middle of flu season, lighten up on your workout or take a day off. If you are coming down with the flu, another hard workout might leave you to suffer harder and longer than necessary. Never run if you have a fever. Severe complications such as heart inflammation can result from strenuous exercise when in the grip of a fever. If your symptoms are "above the neck" only, as in stuffy nose and scratchy throat, go ahead if you feel like it, but cut back on duration and intensity.

If your luck runs out and the beast levels you, here is a little guidance beyond the usual army of over-the-counter remedies. As soon as you think you may be getting the flu, call your doctor. He might be able to prescribe one of the anti-flu medications that could result in a shorter, milder infection. Drink lots of liquids, skipping caffeine. Use ice for a sore throat.

Although the research is mixed on "natural" remedies, some show promise. You can try ginger, which may help for nausea, fever, and pain. Put extra garlic in your soup--it has an antibiotic effect and may help stave off secondary bacterial infections. Use steam to help keep nasal passages open and moist, and to lessen chest pain associated with congestion. Don't forget the antioxidant power of fruits and vegetables. Keep your diet rich in the rainbow colors available to you. Eat veggies fresh, juice them, and toss them into your soup pot.

What about zinc and Echinacea? In neither case is the research conclusive; reviews have been mixed on zinc. Some studies show shortened duration of upper respiratory infections as compared to placebo, while other studies show no difference. Newer nasal spray versions have shown promising results, in one study, reducing a cold's duration by two days as compared to zinc tablets. Echinacea has long been touted to thwart viruses in German studies, and U.S. sales suggest we are convinced. A new placebo-controlled, randomized, double-blind study resulted in an average difference of nine sick days for placebo and only five for the Echinacea-treated group. Almost no significant side-effects have been observed for either treatment. So, if you're so inclined, give them a try. However, don't use either one on a long-term basis--at best, chronic use diminishes effectiveness.

(American Journal of Preventive Medicine, 2001, Vol. 21, No. 2, pp. 79-83; Journal of Sports Medicine and Physical Fitness, 1999, Vol. 39, No. 1, pp. 1-11; Medicine and Science in Sports and Exercise, 2000, vol. 32. No. 7, supplement; Epidemiology, 2001, vol. 12. No. 3, pp. 345-349; Ear Nose and Throat Journal, 2000, Vol. 70, No. 10, pp. 778-780, 782; Arzneimittelforschung, 2001, Vol. 51, No. 7, pp. 56.568; New England Journal of Medicine, 2000, Vol. 343. No. 18, pp. 1282-1289 and Prescription for Nutritional Healing, 2nd edition, by James F. Balch, M.D. and Phyllis Baich, C.N.C., Avery Publishing Group, Garden City Park, NY, 1997, 600 pages, $19.95)

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* Scale back your training. Cold and flu season may be the perfect time to plan additional relative rest and recovery into your training. Crank it up again in the spring when the risk of flu and colds returns to normal.

* Flu shots. The CDC is now recommending flu vaccinations for everyone over 50. Yet the vaccine is often in short supply leaving many of us, especially younger runners, unprotected.

* Anti-flu medications. Doctors now have several anti-viral medications available to do battle with the flu if you get it. Relenza, rimantadine, amantidine, and new inhaled zanamivir and oseltamivir can help soften the sting of a case of the flu including less severe symptoms and a shorter course of illness if taken within two days of symptoms. Some medications may actually prevent certain types of flu.

* De-stress. Whether your life is beset by stressful events or you simply feel stressed is of little consequence to your immune system. Stress hurts and one of the ways it gets you is to reduce your resistance to infections, maybe up to three times that of your unstressed counterparts.

* Clean up. The single best thing you can do to keep well is to WASH YOUR HANDS frequently. Flu sufferers can spread the virus before they know they have it and up to a few days after they feel better. Washing your hands with lots of soap and warm water helps keep the virulent germs away from your mucus membranes--eyes, nose, and mouth--where they can make quick progress infecting you. If you don't have access to water and soap, use an anti-bacterial waterless cleanser until you can wash.

* Keep yourself well hydrated. Dehydration can give microbes a running start against your immune system.