You've developed a healthy exercise program and are determined to stick with it – until you get a cold. Most garden-variety head colds aren't bad enough to keep you from moderate exercise, but when a cold develops into chest congestion, it's a different story. Although you should always check with your health care provider before exercising while sick, chest congestion may just be one time you can excuse yourself from exercise without any guilt.
When a head cold moves to your chest, it's called acute bronchitis, due to the inflammation of the bronchial tubes in your lungs. As the tubes swell, they produce mucus which can lead to a cough, chest soreness and shortness of breath. Bronchitis is also often accompanied by fatigue, headache, mild body aches, watery eyes, a sore throat and a low-grade fever less than 102 degrees F.
Bronchitis can sometimes develop into more serious lung problems, such as pneumonia, and if you smoke, emphysema, right-sided heart failure or pulmonary hypertension. If you have repeated bouts of bronchitis, it could also signal an underlying asthma condition or other lung disorders. When you exercise, your lungs are called upon to increase oxygen intake to fuel your body's cells, which can put further stress on your already-inflamed lung tissues and potentially worsen chest cold symptoms.
A paper by Michael Gleeson, with the School of Sport and Exercise Sciences at Loughborough University in the United Kingdom, reviewed the effects of exercise on immune function. As he reported in the February 2007 issue of the "Journal of Applied Physiology," regular moderate exercise is associated with a reduced risk of infection. However, prolonged bouts of strenuous exercise can cause a temporary depression of your immune function for up to 24 hours after exercise, depending on the intensity and duration. This effect is most pronounced when exercise is continuous, prolonged, moderate to high intensity and performed without consuming any food. He concludes that the combined effects of small changes in several immune parameters during exercise may compromise your resistance to an upper respiratory tract infection. Edward R. Laskowski, MD, of MayoClinic.com, cautions that as a general rule, proceed with your workout if your symptoms are "above the neck," but postpone your workout if your symptoms are "below the neck."
Although most cases of bronchitis clear up on your own, the Centers for Disease Control and Prevention cautions that you should see your health care provider if your temperature rises higher than 100.4 degrees F, you have a cough that produces thick or bloody mucus, you have trouble breathing, your symptoms last more than three weeks or if you have a chronic heart of lung problem. If you suffer from chronic bronchitis, usually caused by smoking, then John M. Heath, MD, and Rupa Mongia, MD, with the American Association of Family Physicians, explain that exercise can actually be beneficial. They recommend graded aerobic exercise, such as walking or bicycling, over progressively longer durations three times a week, with oxygen supplementation as needed.