Real Simple shares information on over-sleeping and what sleeping more than 9 hours can imply.

If you find it hard to drag yourself out of bed even after nine hours of sleep, it could be a sign of an underlying medical condition—such as untreated sleep apnea, which can make sleep more shallow and therefore of poor quality—says Grandner. “This can lead to a desire to sleep more because sleep isn’t restful enough,” he adds. It could also be a sign of depression, which can drain your energy and make it difficult to get out of bed.  Grandner advises anyone who feels like they need more than nine hours of sleep to feel rested should consult a doctor to determine what could be going on.