Teenage brains work two hours behind adult time. They get up later because they are biologically programmed to do so. Dr. Paul Kelly, author of Making Minds, says that continuous early starts create "teenage zombies" and that allowing teenagers to begin lessons at 11am has a profound impact on learning. Rousing teenagers from their beds early results in abrupt mood swings, increased irritability, and may contribute to depression, weight gain, and reduced immunity to disease. (Robinson, Ken, Sir, PhD. Out of Our Minds. p 260-261. NY: Capstone Publishing Ltd, 2001, 2011)