SUNDAY, Oct. 25 (HealthDay News) -- To keep colds at bay during the chilliest months of the year, exercise just might be the key.

David Nieman, a representative of the American College of Sports Medicine, says that studies have shown that people who exercise at least 45 minutes four or more days a week take 25 to 50 percent less time off from work because of illness.

"This reduction in illness far exceeds anything a drug or pill can offer," Nieman said in a news release from the sports medicine group. "All it takes is a pair of walking shoes to help prevent becoming one of the thousands predicted to suffer from the common cold this winter."

But what if you're already under the weather? Should you try to get some exercise? Nieman suggests:

• If a cold is only in your head and has not reached your chest, feel free to exercise.
• Don't overexert yourself. That means no running: Just take a walk. Studies have not shown that moderate exercise is bad if you have a cold.
• If you have symptoms beyond the sniffles, stay in bed. This advice holds if a cold has traveled to your chest, if you have severe aches and pains and if you're running a fever. Swollen glands spell trouble, too.
• Take it slow when recovering from anything but a mild bout of illness. Take a couple of weeks off from exercise before you start workouts again.

Nieman has one more bit of advice: Exercise before you get your flu shot because research has shown that moderate-level physical activity will boost your immunity in the long run.

SOURCE: American College of Sports Medicine, news release, Oct. 6, 2009

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