A study by Iowa State University researchers shows a treadmill or running shoes might be something to add to your arsenal of weapons to fight the flu. Professor Marian Kohut studied the impact of the flu on mice who had been given regular exercise on a treadmill.

Kohut says moderate exercise performed for several months did end up reducing the amount of the virus in the lungs of the mice and those that exercised also had less of the “inflammatory factors” that caused inflammation in the lungs. Kohut, an associate professor of kinesiology, says the benefits of even a small amount of exercise were apparent in the mice.

Kohut says: “What was surprising as well, is that we found that even one session of exercise prior to exposure to the flu virus actually had some protection. The symptoms of the infection were less severe for a few days after the infection onset.” Kohut says this study does back up an earlier study on exercise and the flu in humans.

She says they did publish a study several years ago a study on the flu vaccine in older adults, where one group of adults exercised moderately three times a week for a year while the other group remain sedentary. Kohut says the group that exercised had moderately higher levels of antibodies when they came in the next year for the flu vaccine — which suggested better protection against infection. But don’t think jumping on your bike or treadmill will help you once you’ve already come down with the flu. Kohut says the evidence shows the exercise helps before you get the virus, and can actually hurt you if you are already sick.

“Exercise, especially prolonged or very strenuous exercise after infection, typically can make that infection very severe,” Kohut says. Kohut says they know that being healthy helps you fight off sickness, but they want to find out more about the impact of exercise in holding off the flu.

She says they will be looking to see if exercise makes it tougher for the virus to attach to the lungs of mice who have exercised. Kohut says they already have some evidence that different parts of the immune system are enhance by exercise, and they want to find out more how that works. The study is part of a five-year project by I.S.U. researchers, funded by the National Institutes of Health.