Sleep Need: How Much Sleep and What Kind?

Abstract

The authors studied 29 healthy men who habitualy slept nocturnally for long or short periods. The short sleepers were efficient, hardworking, and somewhat hypomanic: the long sleepers tended to be anxious, depressed, and withdrawn. Both groups had similar slow-wave-sleep (SWS) time, but the long sleepers had twice as much D (REM) sleep. The authors suggest that there are two separate requirements—a relatively constant requirement for SWS and a requirement for D sleep that is related to the individual's personality and life style.