Epigenetics of physical exercise is the study of epigenetic modifications resulting from physical exercise to the genome of cells. Epigenetic modifications are heritable alterations that are not due to changes in the sequence of nucleotides. Epigenetic modifications, such as histone modifications and DNA methylation, alter the accessibility to DNA and change chromatin structure, thereby regulating patterns of gene expression. Methylated histones can act as binding sites for certain transcription factors due to their bromodomains and chromodomains. Methylated histones can also prevent the binding of transcription factors by hiding the transcription factor's recognition site, which is usually found on the major groove of DNA. The methyl groups bound to the cytosine residues lie in the major