Sleep deprivation, or sleep debt, is a very common condition in the lifestyles of many individuals. This condition has a profound effect on the endocrine system, leading to cardiovascular complications among other disturbances. Sleep deprivation decreases insulin sensitivity and is associated with metabolic control in diabetic patients. Other hormones such as cortisol, growth hormone, insulin-like growth factor-1, prolactin, leptin, thyroid hormone, and dehydroepiandrosterone sulfate, as well as the regulation pathways of these substances, are affected by the quantity and quality of sleep. Therefore, sleep loss has important implications in the prevention and treatment of the metabolic syndrome and other diseases.