Epigenetic modifications as outcomes of exercise interventions related to specific metabolic alterations: a systematic review

Background: Chronic diseases arise as a consequence of an unhealthy lifestyle primarily characterized by physical inactivity and unbalanced diets. Regular physical activity can improve health, and there is consistent evidence that these improvements may be the result of epigenetic modifications. Objective: To identify epigenetic modificationsas outcomes of exercise interventions related to specific metabolic alterations. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) methodology for manuscript research and preparation was followed using PubMed and EBSCO databases for literature review. Out of 2,638 articles identified, only 34 articles met the inclusion criteria. Results: The sections of the review were organized by metabolic alterations in which studies were grouped according to healthy, diseased, and trained individuals. Resistance exercise in humans induced epigenetic changes in pathways associated with energy metabolism and insulin sensitivity, contributing to healthy skeletal muscle. Endurance exercise also caused modifications in biomarkers associated to metabolic alterations through changes in DNA methylation and the expression of specific miRNAs. However, both resistance and endurance exercise are necessary to obtain a better physiological adaptation and a combination of both seems to be needed to properly tackle the increasing prevalence of non-communicable pathologies. Conclusion: Given the heterogeneity and complexity of the existing literature, it is currently not possible to propose a specific recommendation about the type, intensity, or duration of exercise that could be beneficial for different subsets of the population (healthy, diseased, and/or trained). Nevertheless, this review highlights the importance of exercise for health and shows the need to perform more research in this emerging area to identify epigenetic biomarkers that could serve as indicators of exercise adaptations