Are You Immune Enough?

Philip J. Goscienski, M.D.

September 2007

Is your immune system up to speed? Possibly not if you are middle-aged or older, if you don't exercise regularly or if your protein intake is lower than it ought to be for your activity level.

Our Stone Age ancestors needed to fight off countless forms of infectious disease germs from the tiniest viruses to twenty-foot tapeworms. It's no wonder that in the course of hundreds of thousands of generations the human immune system became so complex.

Modern plumbing and safe water supplies have eliminated most of the threats of infection that our ancestors faced. Vaccines protect us from many others and antibiotics take care of most of the rest. Or do they?

There are plenty of reasons why you should keep your immune system in good shape. Antibiotic-resistant bacteria are on the upswing. Parasites find their way into water supplies in spite of chlorine or other disinfecting agents. Most viruses are unstoppable because anti-viral drugs work on so few of them. Mass-production and widespread distribution of food guarantee that when contamination occurs, disease outbreaks involve several states at once. Infections that are acquired in hospitals kill or cripple thousands of Americans every year, especially among the older generation.

As an infectious diseases specialist I've puzzled for decades over why an epidemic will strike down some persons while others skate through, totally unaffected. Some of the answers may lie in our Stone Age roots.

The hunter who carried or dragged his prey back to the campsite used several times more calories than we do as we push a cart through the supermarket. One of the benefits of physical activity is a stronger immune system. Persons who exercise regularly at a moderate level get fewer colds than couch potatoes do. Exercisers also get a better response to influenza vaccine. Scientists are able to measure several indicators of immunity that get stronger with more physical activity.

Exercise builds muscles that form a valuable storehouse of protein. That reserve supply comes in handy when food supplies get tight. Protein forms the building blocks of germ-devouring white cells and antibodies. We also need protein to replenish layers of skin that form a barrier to germs that attack us from the outside. We replace the inner barrier, the lining of the intestinal tract, every 2 weeks. If we don't get enough protein those barriers break down and allow germs to enter the bloodstream.

Daily exercise is a key element in preventing type 2 diabetes even in those who have a strong family history of it. Diabetics have an increased susceptibility to infection not only because their immune system doesn't function as well but because poor circulation to every part of the body makes it difficult for protective white cells and antibodies to reach tissues where disease-causing germs are setting up housekeeping.

The oldest among us are the most likely to need hospital care and thus expose themselves to germs that have become resistant to antibiotics. It's critical that we do not let our immune system lie fallow but to keep it well-tuned by regular exercise.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at