How much sleep does a person need to have adequate functioning?

The range of normal is 5 to 10 hours.  Some people who are short sleepers only need 5 hours and they wake up refreshed and have optimal functioning during the daytime.  Others need 10 hours to accomplish that.  Sleep deprivation is almost like putting in a deposit or a withdrawal from a bank. If you don’t get adequate sleep time for your body needs,  you are accumulating a sleep debt.  You really can’t make up a chronic sleep debt over a weekend.  It really takes weeks to make up for a sleep debt for someone who has chronic sleep deprivation.