Effectiveness of Aerobic Exercise in Adults Living with HIV/AIDS: Systematic Review

Kelly O'Brien; Stephanie Nixon; Anne-Marie Tynan; Richard H. Glazier

Disclosures

Med Sci Sports Exerc. 2004;36(10) 

In This Article

Discussion

We could not confirm an overall effect of aerobic exercise on CD4, viral load, or O2max, either in individual studies or in meta-analysis. Despite statistical nonsignificance, results demonstrated the possibility of clinically important improvements in O2max among exercisers compared with nonexercising controls, and greater improvements in O2max among individuals exercising at heavy versus moderate intensity. Eight of the nine individual studies that measured cardiopulmonary status demonstrated statistically significant improvements in various cardiopulmonary parameters among exercisers. The fact that results did not reach statistical significance may have been due to a lack of statistical power to detect a difference secondary to small sample sizes, or inadequate intensity, duration, and mode of exercise prescribed within the individual studies. The five studies that measured psychological status among an exercise versus control group found statistically significant improvements in psychological parameters for the exercise intervention groups compared with the nonexercising control groups.

Results of this review indicate that aerobic exercise for adults living with HIV appears to be safe. This finding is based on the absence of reports of adverse events among exercisers. The stability of immunological and virological measures during regular aerobic exercise can also be seen as evidence for the safety of this intervention. These results are based on those participants who completed the exercise programs and for those where there was adequate follow-up data.

The results of this systematic review should be interpreted cautiously for a variety of reasons. First, this review is based on a small number of trials. Furthermore, the trials included in this review involved relatively small numbers of participants, a variety of exercise interventions, and generally poor participant compliance with these interventions. The ability to perform meta-analyses was limited due to the breadth of outcome measures used in the trials. As a result, meta-analyses were underpowered to detect improvements in CD4 count and cardiopulmonary fitness that were of potential clinical importance. Additionally, publication bias may have occurred in this review if trials with negative results were suppressed in the published literature, leaving mostly small, but positive studies to include in the review.

It should also be emphasized that the exercise groups were fraught with high drop-out rates, and that for the most part, participants who dropped out of the exercise program were not included in the final results. This limited comparability of the remaining exercisers with nonexercising controls, which raises issues of effectiveness and safety of exercise among those who stop exercising. Future studies should make every effort to include all subjects in an intent-to-treat analysis with complete follow-up and reporting of results for those who drop out of exercise programs. Furthermore, training intensities were estimated using maximal testing in only three of the included studies. As a result, O2max might have been underestimated in other studies that used alternative methods (e.g. submaximal testing) to estimate their training intensities. This could have resulted in an overestimation of training intensities in these studies.

The vast majority of study participants were male and between the ages of 18 and 58. As such, findings should be interpreted cautiously with respect to females and/or people living with HIV/AIDS who are children, young adults, or older adults. Additional high-quality studies are required to further investigate the effects of aerobic exercise in adults at varying stages of HIV/AIDS, particularly those who are severely immunocompromised. The long-term effects of exercise also require attention. All studies were conducted for 12 wk or less, except for one 24-wk study. Further research should also explore the different effects of interval versus constant exercise, as well as aerobic exercise in conjunction with other exercise modalities. The purpose of this systematic review was to investigate the effects of aerobic exercise; however, future reviews should also explore the effects of progressive resistive exercise in this population.

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