In the Running or Run-Down? Don't Let Exercise Impair Your Immune Function

Exercise is goof for you, but athletes who train hard sometimes catch more colds and have more sick days than their less-active peers. Many athletes tend to come down with an upper respiratory infection in the days following a big contest, such as a marathon or a tournament requiring hours of intense activity. Too much exercise, especially when accompanied by inadequate nutrition and an out-of-balance lifestyle, can lead to an energy deficit that leaves the immune system run down and unable to perform at its best.

It's a question of balance. Research shows that moderate amounts of exercise improve immune function. Regular exercisers are sick fewer days each year, and, in the laboratory, their immune systems generally perform better than those of their sedentary friends.

Is moderate not part of your vocabulary? To be the best, sometimes you've got to train hard, and some sports require extreme levels of exertion. If this is you, then be sure to take extra measures to stay healthy, so that you don't lose training days or suffer poor performance because of sickness. Pay attention to the factors that help keep you healthy and allow you to train without reducing the effectiveness of your immune system.

Here's what you can do to prevent high volumes of exercise from interfering with immune function.

Manage stress

Excess exercise appears to exert its negative effects on the immune system by stimulating the production of stress hormones. Stress hormones are meant to help get you out of a tight situation by activating the fight or flight response. In the interest of surviving imminent danger, nonessential functions, such as the immune system, are put on hold.

The trick is to keep general stress levels as low as possible so that exercise does not reach the "excess" level. Exercise is most likely to be perceived as stress when you are already stressed in other areas of your life, such as work, school or relationships.

Watch for symptoms of overtraining

Frequent illnesses and injuries are often indicators of overtraining. So are elevated resting heart rate, difficulty sleeping, fatigue, depression and an unexplained decline in athletic performance. If you have symptoms of overtraining, train for shorter periods, cross train and take more rest days.

Get plenty of sleep

The immune systems of rested people are much more effective at responding to pathogens than the immune systems of the sleep-deprived. Sleep also allows muscles to heal after tough workouts. Regular rest, sleep and recovery are important components of every training cycle.

Avoid germs

Germs are everywhere, so adopt habits that will keep them out of your body. Avoid crowds as much as possible in the weeks away from sick people. The hands are the most common source of infection, so wash hands often and well. Also, touching your nose or eyes gives cold germs an express ride to the home of their dreams: your mucus membranes.

Pay attention to your diet

Athletes restricting calories or avoiding certain food groups are most at risk of nutritional deficiencies that can compromise immune health. All athletes should pay extra attention to the following:

• Adequate hydration keeps mucus membranes healthy, providing the best operating environment for patrolling immune cells.
• Protein is what immune cells are made of Athletes training at high levels need more protein than most people (about 1.2 to 1.6 grams of protein per kilogram of body weight).
• Carbohydrate consumed before and during exercise reduces the stress hormones that suppress immune response. Studies suggest keeping glycogen stores up, and consuming 30 to 60 grams of a carbohydrate beverage during prolonged exercise to help protect immune function.

Many vitamins and minerals play important roles in the health of the immune system, especially vitamins A, C, E, B6, B12 and folate, and minerals iron and zinc. Taking megadoses of these nutrients, however, does not appear to improve immunity. Megadoses of some nutrients can even make you more likely to get sick! If your diet is not always what it should be, a multivitamin and mineral supplement that supplies up to 100 percent of the RDA for most nutrients is a good idea.

Barbara A. Brehm, Ed.D., is professor of exercise and sport studies at Smith College, Northampton, Mass.

 

Title In the Running or Run-Down? Don't Let Exercise Impair Your Immune Function. Author Brehm, Barbara A. Journal Fitness Management Publisher Leisure Publications Date 22(2) Feb 2006 Pages p.23 SIRC Article # S-1010064 This material has been copied under license from the Publisher. Any resale for profit or further copying is strictly prohibited.

 

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