DEAR DOCTOR K: I read about a new study on sleep and memory. I understand why too little sleep could affect memory. But why would too much sleep be harmful?
DEAR READER: When it comes to memory, sleep is a Goldilocks issue: Neither too much nor too little is good.Aim for "just right," says Dr. Elizabeth Devore, an instructor in medicine at Harvard-affiliated Brigham and Women's Hospital. Dr. Devore led a new study that suggests getting an "average" amount of sleep -- seven hours per day -- may help maintain memory in later life.