Epigenetic changes are modifications to gene expression that do not involve changes in the nucleotide sequence [125]. Even though epigenetic changes do not affect the nucleotide sequence, these changes can persist through multiple cell divisions and across generations [126]. Recent research has indicated that BDNF is upregulated through epigenetic changes. For example, Gomez-Pinilla and colleagues observed increases in rat hippocampal BDNF mRNA and protein through mechanisms of epigenetic regulation after one week of voluntary exercise [87]. Researchers have posited that exercise promotes epigenetic changes, thus promoting homeostasis, including neural plasticity, circadian rhythms, and endocrine and immune regulations [127]. Other investigators have proposed that the epigenetic changes produced through exercise, which they call “eustress” or good stress, can reduce the aging process and have beneficial effects on the musculoskeletal system across the lifespan [128]. Based on recent research, it is possible that exercise is associated with epigenetic changes that are beneficial for individuals with mood disorders [27].
