According to Lawrence J. Epstein, M.D., Program Director, Sleep Medicine Fellowship Program, Brigham & Women’s Hospital, the exact amount of sleep needed will vary by the individual. While the average range is seven and a half to eight and a half hours, the exact amount varies. It could also be more like nine to ten or five to six hours. What is important is determining what is the right amount for you.To learn the correct amount for you, Epstein recommends testing it out at a time when you are able to sleep as much as you’d like, without an alarm clock for example, or when you are on vacation. At first, says Epstein, you will probably sleep more as you make up for whatever deficit that you might have. After a few days, however, you will settle into a pattern of sleeping a consistent amount of time. This is the amount of sleep that you personally need.According to Epstein, you will know that this is the correct amount of sleep for you if you are waking up feeling rested and restored.