Jerome Siegel: If you don't have continuous sleep, it's not restorative, it's not restful. Dr. Dean Edell: Lack of sleep causes inattentiveness and learning difficulties, but there is a bigger question. Jerome Siegel: Under extreme conditions in animals, if they're totally sleep deprived for periods of weeks, they will die. They'll die sooner than if they don't get food. Dr. Dean Edell: During sleep heart rate, blood pressure and temperature drop. The body also secretes growth hormones that regulate body mass and appetite. Esra Tasali: Sleep deprivation has significant detrimental effects on our metabolism, on our endocrine function and especially on our carbohydrate metabolism. This will again measure your eye movements during your sleep. Dr. Dean Edell: A recent study shows when healthy volunteers are sleep deprived, they become pre-diabetic in just one week. Lack of sleep also creates problems for dieters. Esra Tasali: The appetite hormone ghrelin goes up, which again signals to brain that you have to have more food. Dr. Dean Edell: Most scientists agree, sleep boosts the immune system and gives not only the body but the brain a much needed break. I'm doctor Dr. Dean Edell.