Endometriosis, an estrogen dependent disease, is a gynecological disorder characterized by the growth of endometrial tissue outside the uterine cavity resulting in pain and discomfort. Estrogen plays an important role in the growth and persistence of endometriotic tissue along with inflammation. Estrogen receptor alpha (ERα) expression is significantly higher than estrogen receptor beta (ERβ) in normal endometrium. Endometriosis patients have increased abdominal fat which might contribute to a local endometriotic inflammatory environment characterized by infiltration of macrophages and secretion of proinflammatory cytokines. Furthermore, there is a dysregulation in this ratio, where lesions show increased expression of the ERβ and reduced expression of ERα. These receptors are also present in visceral fat and dysregulation of their function is known to correlate with increased adipose tissue. Preliminary data in our lab found increased mesenteric fat and serum leptin levels in endometriosis animals, which are decreased by exercise. However, it is still unclear how exercise modulates ER expression and whether it can improve endometriosis in an animal model.