Sleep Sleep Sleep is a period during which a person rests body and mind.
Sleep restores energy to the body, particularly to the brain and nervous system.
Persons who go without their normal amount of sleep lack concentration and become quick-tempered. A person's sleeping patterns develop gradually. Newborn babies sleep for periods throughout the day and night. By the age of two or three months, many babies have learned to sleep through the night, though they nap for periods during the day. By the age of four, most children have given up daytime naps.