Moderate Exercise Helps Fight Cold, Flu
I know the calendar says Spring is here, but the weather has yet to join the fun for more than a day or two. When it warms up officially, the last thing we want is a lingering cold. To help stay healthy, exercising can be a key part of your life.
Ingrid Ozols Perdue runs several miles a week, lifts weights, cycles, does Pilates and even gets in an occasional kickboxing workout -- a regimen she credits with keeping her free of colds and the flu.
"I really haven't been ill," said the 50-year-old dermatologist from the Indianapolis suburb of Carmel. "I think I'm healthier when I exercise. I think it's positive for me."
Experts say she's right -- to a point.
Research shows moderate amounts of aerobic exercise such as jogging, brisk walking and cycling during the cold and flu season boost the body's defenses against viruses and bacteria.
But at a certain point, the physical stress of a long workout undermines the immune system and leaves the endurance athlete even more vulnerable to infection than before a workout.
"The general consensus, I believe, is that 30 minutes, three or four times a week, is generally considered to have positive effects," said Michael Flynn, who studies exercise's effects on the immune system at Purdue University in West Lafayette.
One study showed that jogging about 10 miles a week was beneficial to the body's defenses, but 20 miles was associated with an increased risk of infection, Flynn said.
"There's pretty good evidence that the intensity of prolonged exercise suppresses certain aspects of the immune system," Flynn said. "If someone is just doing fitness exercise, it seems like their resistance is better."