SLEEP 2011 Abstract Supplement

A. Basic Science VI. Chronobiology
differences may involve both stable trait characteristics and specific responses
to increased sleep pressure.
Support (If Any): This work was supported by a CIHR grant and
NSERC fellowships.
0152
SLOW WAVE SLEEP IS CONSERVED DURING A
SIMULATED SHIFTWORK SCHEDULE
Satterfield B, Bender AM, Belenky G, Van Dongen H
Sleep and Performance Research Center, Washington State University
Spokane, Spokane, WA, USA
Introduction: Under sustained moderate sleep curtailment, slow wave
sleep (SWS) has been found to be selectively conserved. We investigated
whether SWS is also conserved under circadian manipulation of
sleep timing.
Methods: N=27 healthy young adults (ages 22-38; 14 females) participated
in a 14-day in-laboratory study. 13 subjects were randomized to
a simulated shiftwork condition. After a baseline day with 10h nighttime
sleep (TIB 22:00-08:00), subjects had a 5h nap (TIB 15:00-20:00),
and entered a five-day nightwork period intervened by four 10h daytime
sleep opportunities (TIB 10:00-20:00). Subsequently, they had a 5h nap
(TIB 10:00-15:00) before rotating back to a baseline day with 10h nighttime
sleep (TIB 22:00-08:00). Beginning with the first nap, the pattern
then repeated itself. 14 subjects were randomized to a control condition
with 10h nighttime sleep (TIB 22:00-08:00) daily. There were 13 sleep
opportunities in the control condition, and 15 in the shiftwork condition,
but cumulative TIB was the same. In the control condition, two out of
every three 10h nighttime sleeps were PSG-recorded. In the shiftwork
condition, the 10h baseline nights, 5h nap opportunities, and middle pair
of each four 10h daytime sleeps were PSG-recorded.
Results: Mixed-effects ANOVA comparing SWS between sleep opportunities
and conditions yielded a significant interaction (F[8,199]=9.80,
P