Resistance Training Impact On Immunity In Apparently Healthy And Hiv-Infected Individuals: Systematic Review And Meta-analysis

Purpose: This systematic review examined the evidence available on the impact of resistance training on immunological parameters in apparently healthy and HIV-infected individuals. Methods: The Pubmed and Ebscohost (which included a complete MEDLINE search) databases were searched on the 4th (427 articles) and 18th (383 articles) of October 2013 for articles using the terms “resistance training” AND “HIV” and either of the following “immunity” “CD4+” “CD8+” “CD4+/CD8+ ratio” and “T cells”. Articles were eliminated if they were redundant, non-human, not in English, used an intervention other than an acute bout of resistance exercise, did not measure any of the immune parameters pre and immediately post training or used a minimum of 1 set of 8 repetitions for the exercise bout. Titles and abstracts of all citations were reviewed independently by two reviewers to identify studies that met the inclusion criteria. Reference lists were hand searched for additional articles not identified in the search. Results: Four studies (three healthy and one HIV population) were included and a total of 16 Cohen’s d effect sizes were calculated for the effect of an acute bout of resistance exercise on CD4+, CD8+, CD4+/CD8+ and T cells. CD4+ effect sizes were calculated from 61 healthy subjects and ranged from trivial (d = 0.1 95%; CI -0.7, 0.8) to large (d = 1.3; 95% CI 0.4, 2.3). CD8+ effect sizes were calculated from 61 healthy individuals and ranged from small (d = 0.3; 95% CI -0.4 -1.0) to medium (d = 0.5; 95% CI -0.4, 1.4). The effect size for
the CD4+/CD8+ ratio of 17 healthy individuals was trivial (d = -0.18; 95% CI -1.1, 0.7 95% CI). Effect sizes for T cells in healthy individuals were large (d = 1.3; 95% CI 0.2 and d = 1.6; 95% CI 0.5, 2.7). In 28 HIV-infected individuals the effect sizes were moderate for CD4+ (d = -0.5; 95% CI -1.2, 0.3) and CD8+ (d = 0.6; 95% CI -0.2, 1.3). Conclusion: The magnitude of the effect sizes suggest that acute resistance training increases circulating total T cells, T helper cells (CD4+) and cytotoxic T cells (CD8+) in healthy individuals, but attenuates circulating T-helper cells whilst increasing cytotoxic T cells in HIV-infected individuals. This study highlights the lack of evidence and standardization of
research within the field of resistance training and immunity both in apparently healthy and HIV-infected individuals.