The purpose of the present study was to evaluate the simultaneous effects on sleep of prior time awake (PRW) and @entity227 ( @entity227 ). Eight male subjects spent 13 days in an isolated sleep lab and had three 8-h baseline sleeps and then 18 4-h sleeps, distributed to provide three sleeps starting at 2400, 0400, 0800, 1200, 1600, and 2000. The three sleeps were preceded by 4, 8, and 12 h of PRW, respectively. ANOVA showed that @entity24 and subjective sleepiness increased with PRW and with closeness to the trough of the circadian rhythm of rectal temperature, whereas sleep latency showed the opposite pattern, and rapid eye @entity10522 (REM) latency strongly decreased with PRW and with closeness to the trough. @entity25 ( @entity25 ) increased with PRW, whereas @entity25 latency and final time awake decreased. REM sleep increased with closeness to the circadian trough, and time awake decreased. Multiple-regression analysis showed that REM latency was closely related to increased @entity25 in the first sleep cycle, reduced @entity25 latency, and increased PRW [a short PRW before sleep at noon yielded an extremely short (14 min) REM latency]. Sleep latency and final time awake showed almost exactly the same relationship to @entity227 and PRW. It is concluded that both homeostatic and circadian influences simultaneously affect sleep, that REM latency is very sensitive to the need for @entity25 , and that the circadian acrophase strongly interferes with sleep. It should be emphasized that the conclusions should not be extrapolated to longer (> 12 h) wake spans.

Experimental separation of XXXX and homeostatic influences on sleep.

@entity10522 :: ('MESH:D020189', 'Disease') :: ['movement sleep'] @entity227 :: ('MESH:D014786', 'Disease') :: ['TOD', 'time of day'] @entity24 :: ('7263', 'Gene') :: ['TST'] @entity25 :: ('MESH:D012893', 'Disease') :: ['SWS', 'Slow-wave sleep']
@entity227 :: (MESH:D014786,Disease) :: ['time of day']
