[Changes in temporal organization of sleep stages in man aged from 20 to 70 years [author's transl)]

E.E.G. tracings during sleep were compared in three age groups: 20-30 years, 50-60 years and 60-70 years. There was a marked reduction in stages 3 and 4 as a function of age, an increase in awakenings during the night and in stage I, and a considerable modification in temporal distribution of PS during the night, this being no longer more concentrated at the end of the night but tending to be regularly distributed throughout the night period. The authors emphasize that sleep organization persists in normal subjects up to an advanced age. The average effects of aging (reduction in SWS and increase in awake periods and light sleep) do not necessarily reflect changes occurring in sleep in any given individual. A hypothesis is suggested that the effects of aging rather tend to produce an increase in certain individual sleep characteristics.