What is the clinical implication of these leukocyte changes?

What is the clinical implication of these leukocyte changes?

Can exercise benefit those afflicted with HIV/AIDS or cancer?

Since studies led to some clarification of how immune cells are affected by exercise, it is important to apply this information to clinical situations. Evidence suggests that 45 minutes to an hour of aerobic exercise at 70-85 % of their maximum heart rate causes an increase in the number of CD4 cells in individuals with HIV/AIDS (1,6). This increase only results in normalization of CD4 levels not to supra-normal levels. These increases in CD4 cells are most significant in less immuno-compromised individuals. Additionally, endurance training increases size and number of mitochondria which may counteract the affects of zidovudine (AZT) which has been shown to cause mitochondrial myopathy (3). Finally the increase in levels of endorphins, enkephalins, and natural opiods as a result of exercise can help to reduce psychological stress which has been shown to compromise the immune system and may enhance the well-being of those afflicted with the HIV virus (1).
Much data for the association of exercise and cancer are from epidemiological studies. Because of this fact it is difficult to demonstrate an association between exercise and cancer because of many confounding factors (9). Moderate exercise has been shown to reduce certain types of cancers especially colon tumors and tumors/cancer of the female reproductive tract (9). Those who exercise generally have a healthy lifestyle and diet which may prevent many diseases in and of itself. Exercise does deplete glycogen stores and plasma amino acids which could limit the energy supply of immunological cells (9). In addition, exercise also increases the rate of free radical production which can increase genetic change and tumor production. Fortunately, exercise increases the activity of antioxidant enzymes and augments ascorbic acid and tocopherols reserve (9).

Conclusion

Research in the area of exercise immunology is a relatively new endeavor. Ethical constraints preclude direct human experiments to examine the possible value of regular exercise in the treatment of experimentally-induced HIV and cancer in humans (9). Using exercise to help in the treatment of HIV or cancer patients is also difficult because one cannot ask these population to stop their pharmacological treatment so investigators can study the affect of exercise alone. The use of animals to study exercise's effects are also questionable because does animal models provide a normal, free-living human model (9). This area of research has just started to elucidate the effects of exercise on immune function and this research may prove invaluable in the treatment of disease.