SAN FRANCISCO - Although AIDS patients have been told to avoid strenuous exercise, the results of a study announced today at the experimental Biology '98 meeting show that they can undertake a major workout without increasing their HIV viral load. Exercise may even help to build the body of a patient with AIDS and fight against muscle loss that affects 10% of Americans with AIDS and almost half of Africans suffering from the debilitating disease.
In the past, most doctors have warned AIDS patients to abstain from strength training. When sedentary people first start an intense exercise program, small tears in their muscles stimulate the immune system. Laboratory experiments showed that stimulation HIV-infected immune cells with molecules called cytokines helps the virus replicate and infect other cells. "The concern is that if exercise increases the production of cytokines, it might actually make people sick," said Ronenn Roubenoff, an exercise physiologist at Tufts University in Boston.
. to test these hypotheses, Roubenoff and colleagues tested viral load in 25 AIDS patients taken from a wider exercise study volunteers were asked to exercise vigorously - to stand on a chair and down every second for 15 minutes. Thereafter, and during the following week, the researchers monitored the viral load of patients. None of the patients showed an increase in viral load, although other tests showed increased levels of certain cytokines.
Roubenoff said the body's immune response probably some checks and balances that prevent excess viral replication when the muscles are strengthened. "It appears that exercise for sure, "he said. The researchers plan to publish a long-term study of exercise and AIDS patients in June.
Despite the good news, at least one researcher suggests the data should be interpreted with caution. "I think it is an encouraging result, but I do not think this one particular study should reverse our tips for AIDS patients on exercise," said Arthur Laperriere of the University of Miami, Florida. It notes that many other studies have shown that intense exercise can compromise the immune system in other ways, for example by reducing the number of "natural killer" immune cells, which may help ward off new virus infections.
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