It is time to prepare for cold and flu season. For most people, that means getting a flu shot and stocking up on hand sanitizer. To be sure, getting vaccinated is the most important thing you can do to prevent seasonal influenza (flu). You can further protect yourself by not touching your eyes, nose, or mouth and by washing your hands frequently with soap and water or using an alcohol-based hand sanitizer. You should also avoid close contact with people who are sick since colds and flu viruses can be spread through the air when an infected person coughs or sneezes.
These methods of cold and flu prevention are commonly known. What you may not know is that good nutrition, regular exercise, and even getting enough sleep can have a positive effect on your immune system. Consider this your health and fitness cold and flu season survival guide.
People who participate in moderate exercise on a daily basis have fewer and less severe colds and have up to 50 percent fewer sick days than those who aren’t regularly active. Research in animals and humans shows that exercise increases the activity of certain immune cells called helper T cells. This makes the immune system response to viruses, like the cold and flu, more robust. The strongest evidence is seen when the exercise is moderate in intensity and duration, such as a 30- to 60-minute walk or jog.
More exercise isn’t always better, though. Very vigorous and prolonged exercise can have the opposite effect. Athletes who engage in long, intense training tend to be more susceptible to upper respiratory infections. Research shows that immune function is depressed in the weeks leading up to and after running a marathon, leading to an increased risk of becoming sick. The bottom line is that regular exercise improves your immune system, but very vigorous exercise may not.
Regular exercise also enhances the immune system response to the influenza vaccine. This means that the flu vaccine can be more effective in people who exercise. If you don’t exercise already, you can still benefit: one study showed that a single 45-minute exercise session can improve the immune response to the flu vaccine. You can get this benefit by going for a brisk walk before your flu shot.
Good nutrition is also important for optimal immune system function. Deficiencies of certain nutrients can have a negative effect on immune function, so eating a balanced diet is essential. That said, there is no support for “boosting” the immune system by taking high doses of vitamins, minerals, or other supplements, despite the claims made by supplement companies. In fact, the majority of nutritional supplements have not undergone appropriate testing and for those supplements that have been tested, the results are not consistent with the claims.
Poor sleep habits are associated with suppressed immunity and more frequent illness. Sleep deprivation can also reduce the positive immune response to a flu shot. High levels of stress increase susceptibility to colds and the flu and can lead to more sick days from work or school. Stress and poor sleep habits tend to occur together, creating a double negative effect on the immune system.
In order to have your best chance of staying healthy this year you should exercise every day, eat a healthy diet, manage your stress, and get enough sleep in addition to following the traditional advice to get a flu shot, wash your hands frequently, stay away from people who are sick, and stay home yourself if you are ill.
Brian Parr, Ph.D., is an associate professor in the Department of Exercise and Sports Science at USC Aiken where he teaches courses in exercise physiology, nutrition and health behavior.