Upon initial screening and again within a week of testing, all subjects will have an assessment of 24-hour ambulatory blood pressure. Subject screening will be performed by the Penn State Clinical Translational Research Center (CTRC) medical staff and will include a physical exam by a clinician, anthropometry, and a chemical and lipid profile, liver and renal function. Women will be either postmenopausal (absence of menstruation of >1 year and Follicle Stimulating Hormone (FSH) >25 milli-international units per milliliter (mlU/ml)) and not be taking hormone replacement therapy, or normally menstruating and tested in the early follicular phase of their cycle. Subjects will also go through an assessment of conduit vessel endothelial and vascular smooth muscle function with brachial artery flow-mediated vasodilation (FMD), and sublingual nitroglycerin.