Physical exercise modulates peripheral levels of brain-derived neurotrophic factor (BDNF): a systematic review of experimental studies in the elderly.

Unlabelled: The objective of this study was to conduct a systematic review of studies that analyzed the effect of physical exercise on the peripheral levels of BDNF in elderly individuals.

Method: We conducted a search in PsycINFO, Biological Abstracts, Pubmed, Web of Science, and Science Direct from 1990 to 2011, using the following keywords: "physical exercise", "physical activity", "physical therapy", "training", "BDNF", "neuroplasticity", "neurotrophins", "neuroplasticity proteins", "aged", "older", "elderly". The articles were considered for inclusion in the review if they were studies with elderly, assessed peripheral (serum and/or plasma) BDNF and evaluated an acute exercise or chronic exercise (training).