Change in CD4+ cell enumeration following aerobic exercise training in HIV-1 disease: possible mechanisms and practical applications.
Growing evidence suggests that routine physical activity, by individuals who are HIV-1 infected, may have significant impact on several important components of good health. Some of the physical benefits noted are: an increase in cardiopulmonary fitness, improved muscle function, and weight gain, while psychological benefits consisting of improved mood states and increased active coping behaviors have been observed. However, the emphasis of this paper is on the effects of exercise training on the enumeration of CD4+ cells in HIV/AIDS. A review of all the available literature revealed: (1) no decline in CD+ cell counts seen in any of the studies, regardless of the initial stage of disease, level of CD4+ cells, or symptomatology; (2) a trend toward an increase in the number of CD4+ cells in all but one study, with the more significant increases seen in those subjects at earlier stages of disease; and (3) the importance of homogeneous study samples when investigating the effects of exercise in a dynamic disease, such as HIV/AIDS. With regard to possible mechanisms, psychological stress has been implicated among the cofactors contributing to the immunological decline in HIV-1 disease. Good evidence was presented which supports the stress management role of exercise training as a means to explain the buffering of these suppressive stressor effects, thereby facilitating a return of the CD4+ cell count to more normal levels. We therefore believe that the observed elevation in the number of CD4+ cells actually represents a normalization of CD4+ cells. With regards to practical application, collectively these studies provide reason to encourage HIV-1 infected individuals to begin an exercise training program, preferably while they are in the early stages of disease, and in compliance with the suggested guidelines.