The Fitness Fixer
The Fitness Fixer

Regular Exercise Reduces Cold and Flu Incidence

A giant cold germ is pictured at left.

Studies first started to report the benefit of exercise to reduce incidence of colds when looking at recreational exercisers, who reported fewer colds once they began regular running. Later research on exercise, intensity, and the number of colds, found that people who exercised moderate on most days averaged one cold, while the less active group reported over four colds in the year. Related work shows that being a regular exerciser is also associated with quicker recovery from colds.

Moderate exercise also enhances immune function during the exercise and for a few hours following it. Specific research into mechanisms has found that moderate exercise speeds various immune-function cells through the body, and increases levels of the type of white blood cell called leukocytes that work to fight infection.

A 2006 randomized clinical trial found that "postmenopausal women who exercised regularly for a year had about half the risk of colds compared to those who did not work out routinely." The women in the exercise group also reduced body weight, body fat, and intra-abdominal fat from increasing their exercise level.

Too much intense exercise may lower immune function and predispose to some infectious illness shortly after the time of the exercise. The decrease seems to be temporary, similar to the increase seen around the time of moderate exercise. There is some concern that continual, intense exercise lowers immune function for longer periods. An example often offered for this is that during the Winter and Summer Olympic Games, clinicians report that "upper respiratory infections abound" and that "the most irksome troubles with athletes are infections." The situation may be more that high numbers of young people are concentrated in close quarters. Their high general health may mean that they are unlikely have other health disorders during the short period of the Games.

It is more likely that poor nutrition and insufficient rest, added to harsh, ongoing, strenuous work or exercise, decreases immune function, not just strenuous exercise alone.

Although cold and flu germs are reported to live better in the cool dry weather of fall and winter, if you are cold, caught in the rain or snow, or out in a draft, that does not make you more likely to fall prey to them. Immunology is not my field so I can only repeat what I've read. My understanding is that these germs are all around us most of the time. They are on surfaces all over our home, and workplace. Your immune system keeps them out or eats them if they try to invade (pictured to my level of understanding at right). They don't cause problems unless their number is too high and your immune system cannot deter them. I call germs the jerks of the world - they are always there and are harmless unless conditions let them under your skin with your defenses down.

Much attention is given to disinfecting yoga mats. Give attention to cleaning up your own strength against disease:

We need to start a new trend that Health is Contagious - Make Health Catching! Stand up and stretch. Do good deeds. Go now.


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Photo of cold microbe toy by dantc
Photo of AntiViral cat by surekat

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About the Author


Dr. Bookspan is an award-winning scientist whose goal is to make exercise easier and healthier.