Epigenetic alterations of DNA affect DNA transcription and translation. These alterations occur frequently, however environmental exposures induce epigenetic changes to DNA that would otherwise remain in autoregulatory stasis. This study aimed to look at exercise as a possible environmental factor causing epigenetic change. The study also assessed global DNA methylation in sperm, which may transmit such epigenetic changes via the paternal germ line. Measurements were compared between groups of mice that engaged in chronic exercise or remained sedentary. This study also examined enzymes causing methylation shifts in sperm by comparing levels of mRNA expression of genes responsible for new DNA methylation - DNMT3A, DNMT3B and DNMT3L - in testes. These results were compared between exercise and sedentary cohorts, and in progeny to assess heritability of epigenetic change. The results showed a significant difference in global methylation in the sperm between exercise and sedentary cohorts and a concomitant increase in gene expression in multiple DNMT3 genes.