Winter in New England typically means another round of sniffles, sore throats, fevers, coughs, and aches. While many products claim to prevent these ailments—or at least reduce their severity—simple, aerobic exercise could be your best defense.
People who regularly participate in moderate aerobic exercise get fewer colds. In 2009 the British Medical Journal published a review of several research studies that looked at the effects of exercise on upper respiratory tract viral infections—the kind that cause sore throats and runny noses. The reviewers concluded that, for the average person, moderate physical activity increased immune system function, thereby decreasing the incidence and/or severity of these infections. Interestingly, more isn't better—the studies found that when people of moderate fitness levels participated in extremely strenuous activity, their incidence of infections actually rose in the days after the strenuous event.
The exercise-to-sickness correlation is described as following a J-shaped curve. Sedentary people have a relatively high incidence of colds; those who exercise moderately have the least number of colds; and people who participated in very high intensity workouts succumb to the highest number of colds. The last category could include, for example, people who were good, but not great, marathon runners. These athletes tend to have an increased incidence of upper respiratory tract infections during the two weeks after a race. (For truly world-class athletes the post-race effect was not as apparent, maybe due to the extremely high fitness levels of these individuals.) The take-home message was that, for the vast majority of people, a regular regimen of moderate exercise proved to be the best deterrent to the common cold. This correlation between exercise and reduced infection held true for all adults, even when other factors such as age, gender, eating habits, and overall health profiles were taken into consideration.
The actual reasons why this is true are a matter of active research. Many parts of the immune system are being studied at the cellular and molecular levels to see exactly how increasing one's metabolic rate through exercise affects the body's reaction to viral infection. Two simple, holistic explanations offered by many scientists are that 1) exercise helps reduce stress and 2) exercise helps improve the quantity and quality of sleep. Effectively coping with stress and having good sleep habits are well known to increase immune function, and thereby increase resistance to infection.
A study published this year by researchers at the Karolinska Institute in Sweden confirmed the strong correlation between increasing (but still moderate) physical activity and lower incidences of the common cold. In addition, out of the 1,500 study participants, those who reported to be under "high stress" benefited even more from exercise than did those who reported to lead average or low-stress lives.
Even the most disciplined person will eventually get hit with a cold. When this happens, will exercise make you feel better, faster? In short, yes. Most physicians suggest following the "neck rule." If the cold symptoms are mostly above the neck (i.e., runny or stuffy nose, sore throat) then exercising probably won't hurt and might speed recovery. (Of course, basic courtesy should be considered when working out in a public gym. No one wants to run on a treadmill next to someone who is sneezing and coughing their way through a workout!) However, when afflicted with fever, body aches, and other symptoms that affect areas below the neck, doctors recommend resting for a few days, rather than exercising, to help speed recovery.
Be sure to consult your doctor before starting any exercise program. For more fitness information visit http://sitzmarkfitness.health.officelive.com.