Prolonged sleep is associated with many of the same health problems as insufficient sleep. New research shows that both sleeping too much and sleeping too little are linked to elevated risks of chronic disease in middle-aged adults.
A large-scale study conducted by the Centers for Disease Control found that both insufficient and prolonged sleep are associated with a range of serious and chronic conditions including diabetes and cardiovascular disease.
Researchers defined too little sleep as six hours or less per night. Too much sleep was defined as 10 hours or more per night, and optimal sleep duration was in the range of seven to nine hours.
Source: The Huffington Post