Effects of Exercise on Inflammatory, Oxidative and Neurotrophic Biomarkers on Cognitively Impaired Individuals Diagnosed with Dementia or Mild Cognitive Impairment: A Systematic Review and Meta-Analysis.

Although the effects of physical exercise (PE) on cognitive function in dementia and mild cognitive impairment (MCI) have been largely studied, its biochemical effect is still poorly explored. The aim of this systematic review is to investigate the effects of PE on inflammatory, oxidative and neurotrophic biomarkers of subjects with MCI or dementia. Six electronic databases, (Pubmed, Cochrane Central, Embase, PEDro, PsycINFO and SportDiscus) were searched for randomized controlled trials assessing the effects of PE on serum/plasma biomarkers of elderly with MCI or dementia. After selection process, eight studies were included. Meta-analysis was performed by comparison of changes from baseline, using the random effects method. Meta-analysis showed a significant effect of aerobic exercise on IL-6 and TNF-α decrease and positive effects on BDNF expression. As only one study was included with oxidative biomarker assessment, the effects of PE on oxidative process remains unclear. Finally, even though it was possible to observe positive effects of PE on some biomarkers of MCI and dementia individuals, current evidence does not allow drawing specific practical recommendations such as type, frequency, intensity or duration of PE in these population. Further researches aiming to estimate the PE effectiveness on biomarkers of MCI and AD are needed.