Influence of Exercise on the Human Gut Microbiota of Healthy Adults: A Systematic Review Ortiz-Alvarez, Lourdes Xu, Huiwen Martínez Téllez, Borja Manuel SUPPLEMENTARY MATERIAL accompanies this paper at http://links.lww.com/CTG/A166 OBJECTIVES: To summarize the literature on the influence of exercise on the gut microbiota of healthy adults. METHODS: A systematic and comprehensive search in electronic database, including SciELO, Scopus, PubMed, and Web of Science up to July 5, 2019. Eligibility criterion was original studies conducted on healthy humans including exercise interventions or interventions involving any type of physical activity. RESULTS: The initial search retrieved 619 articles of which 18 met the inclusion criteria, 9 were observational, 4 reported very short-term exercise interventions, and 5 reported medium/long-term exercise interventions. Higher levels of physical activity or cardiorespiratory fitness were positively associated with fecal bacterial alpha diversity. Contrasting associations were detected between both the level of physical activity and cardiorespiratory fitness and fecal counts for the phyla Firmicutes, Bacteroidetes, and Proteobacteria. Higher levels of physical activity and cardiorespiratory fitness were positively associated with the fecal concentration of short-chain fatty acids. Reports on the effects of very shortterm and medium/long-term exercise interventions on the composition of the gut microbiota were inconsistent. DISCUSSION: Higher levels of physical activity and cardiorespiratory fitness are associated with higher fecal bacterial alpha diversity and with the increased representation of some phyla and certain short-chain fatty acids in the feces of healthy adults. Very short-term and medium/long-term exercise interventions seem to influence the fecal counts of some phyla. However, the heterogeneity between studies hampers any strong conclusions from being drawn. Better-designed studies are needed to unravel the possible mechanisms through which exercise might influence the composition and activity of the human gut microbiota. 2020-04-14T12:59:05Z 2020-04-14T12:59:05Z 2020-02-18 info:eu-repo/semantics/article Ortiz-Alvarez et al. Clinical and Translational Gastroenterology 2020;11:e00126. [https://doi.org/10.14309/ctg.0000000000000126] http://hdl.handle.net/10481/61205 10.14309/ctg.0000000000000126 eng http://creativecommons.org/licenses/by-nc-nd/3.0/es/ info:eu-repo/semantics/openAccess Atribución-NoComercial-SinDerivadas 3.0 España Lippincott, Williams & Wilkins