Is exercise making you ill?

In the quest for a strong, beautiful body, you may be doing more harm than good.

22 October 2004
by Troye Lund

In the quest for a beautiful body, many go-getters do strenuous gym sessions before work and return late in the evening for more. Dietitian Karen Protheroe has noticed a trend among these people to catch colds and flu more often than others.

Overdoing it?

Research into the effects of exercise on the immune system started in the early 1900s when coaches noticed that Olympic athletes were more prone to infection. Immunologist Dr Paula Robson says 45 minutes of exercise four times a week is healthy, but anything over an hour a day could make a person more vulnerable to illness, particularly if they are not eating properly, are stressed and are not getting enough rest. Dr Robson’s studies show that the immune system is suppressed and most vulnerable to illness for 24 hours after a three-hour bout of exercise. Professor Tim Noakes of Cape Town’s Sports Science Institute says, "The people at highest risk are those who get up at 4am to train hard, then do a full day of work." He confirms, however, that the right amount of exercise has a positive effect on the immune system. This is why people with HIV/Aids are encouraged to follow moderate exercise programmes.

Maintaining a balance

Personal trainer James Home says don’t train every day. Rest for a day or two in the week and listen to your body for signs that it is not coping, such as lethargy and mood swings. Taking supplements provides the body with extra resources but will not be as effective if you eat incorrectly or live under excessive stress. Don’t start taking supplements when you are ill, they should be part of a daily personal maintenance programme. In most cases a nutritional supplement will take up to 12 weeks to have real or visible effects.

Plant potential 

Many plants and herbs can gear up the body to prevent illness. However University of Cape Town immunologist Professor Paul Potter warns that, although most supplements do no harm, there are no scientific studies to prove that they work for everyone. He recommends taking them for a short while to assess whether or not they are helping you as an individual. Dietitian Claire McMahon says no plant extract is a complete supplement and recommends they are taken in conjunction with a balanced diet and a good multivitamin. "Vitamins and minerals work together, like a rugby team, to leave out some vitamins or minerals is like expecting a hooker and prop to play a game alone," she says. She advises that you check with your doctor before taking these supplements, particularly if you’re pregnant or on medication.

Supplements marketed as immune boosters should not be taken during chemotherapy because they would work against the benefits of the drugs. However, taking supplements once the chemotherapy is over could be useful. Supplements from plant extracts include:

Spirulina: A whole food that has all the enzymes, vitamins and minerals that feed and strengthen the body. Barley grass: Made from the dried juice of young barley plants and said to contain a vast number of amino acids, enzymes, antioxidants, vitamins and minerals that cleanse and balance.

Potato plant extract: Contains sterols and sterolins that help the body fight disease. Claims have been made that it helps HIV patients in particular.

Enchinacea: Stimulates white blood cells to identify, attach to and destroy foreign organisms.

Ginseng: enhances mental and physical capabilities in cases of weakness, exhaustion and during convalescence.

Chinese medicine

Chinese remedies are becoming increasingly popular. They are best taken as a preventative measure or after illness, for short periods. Do not take them when you have a cold or flu because the herbs can aggravate the condition, say manufacturers. Ask expert opinion about a remedy before taking it. Then monitor its effects. Sunshine booster Healthy exposure to ultraviolet radiation in sunlight helps the body produce vitamin D. However, too much sunning oneself in the UV rays can actually suppress the immune system. Eat your way to immunity Deficiencies of iron, zinc and vitamin A can weaken the immune system. Trials in elderly patients have shown that vitamin E can actually ‘switch’ an immune system back on. Remember that mega-doses of anything can be harmful and even reduce immunity.

Other disease fighters

Carotenoids (in yellow, orange and red fruit and vegetables), act as antioxidants that kill invaders.

Vitamin B6 (in nuts, spinach and potatoes) promotes the production of white blood cells. Folates (in pulses and lettuce) also increase white blood cell activity.

Vitamin C (in fruit and vegetables) is a powerful antioxidant and raises the level of immunoglobulin, an antibody against bacteria and viruses.

Vitamin E (in wheatgerm, whole grains and vegetable oil) stimulates immune responses.

Selenium (in tuna, eggs, wholemeal breads) is another antioxidant that attacks invading bacteria.

Zinc (in seafood and eggs) promotes healing and is a defence against the common cold. Garlic is a natural antiobiotic and antioxidant. Cook with it or take it as a supplement.