"Although sleep needs vary, people who sleep about eight hours, on average, tend to live longer. For the long sleepers, we speculate that they are more prone to die because they have undiagnosed sleep apnea or some other disorder. In a sense, the people who have sleep disorders and spend many hours in bed are not really 'long sleepers.' Their sleep is disrupted repeatedly by short, unremembered awakenings that severely cut down on real sleep time." --
Dr. William H. Dement, The Promise of Sleep
