Everyone at some time has had a spell where they didn't get enough sleep and had some of those experiences. John Wolf is a doctor at the Ohio University College of Osteopathic Medicine. So that you can maintain your attention on things that are needing done. Eight hours of sleep seems to be the standard for Americans now, but Doctor Wolf says that's not always been the case. At the turn of the century the average person got about nine hours sleep before the advent of electricity that allowed for regular plant shifts and illumination at night so people had to work or do recreational things.
Some people contend that a nap can bring about a boost in their performance.
Reportedly, Albert Einstein, Winston Churchill, and Thomas Edison were enthusiastic nappers. But Doctor Wolf says for others it doesn't work. Napping can give some people a brief burst of energy. Others it seems to take them longer to regain their concentration and shake off those morning fuzzy thoughts. Then it seems worth.