Sleep cycle content and sleep cycle duration.
D000328:Adult; D000367:Age Factors; D000368:Aged; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010507:Periodicity; D012890:Sleep; D012894:Sleep Stages; D012895:Sleep, REM; D013997:Time Factors; D014851:Wakefulness