SLEEP 2011 Abstract Supplement

A. Basic Science V. Physiology
0107
EFFECT OF SLEEP RESTRICTION ON WHOLE BODY
ENERGY EXPENDITURE IN HUMANS
Markwald RR 1,2 , Melanson EL 2 , Smith MR 1 , Perreault L 2 , Eckel RH 2 ,
Wright KP 1,2
1
Integrative Physiology, University of Colorado, Boulder, CO, USA,
2
Division of Endocrinology, Metabolism, and Diabetes, University of
Colorado Denver School of Medicine, Aurora, CO, USA
Introduction: Short sleep duration is believed to increase risk of overweight
and obesity. One hypothesized mechanism underlying this association
is a reduction in 24h energy expenditure (EE), contributing to
a state of positive energy balance. Previous findings from our laboratory,
however, indicate that one night of total sleep deprivation increased
24h EE measured in a whole room calorimeter. Therefore, we tested
the hypothesis that 5 days of sleep restriction, simulating a work week,
increases whole body 24h EE as compared to a 9h sleep opportunity
condition.
Methods: Eight healthy (4 females), lean (BMI = 22.7 ± 1.3 kg/m2)
adults (24.8 ± 9.1 yrs) completed an inpatient protocol consisting of 3
baseline days (9h sleep/night), followed by two sleep opportunity conditions
(5h or 9h/night, 5 days each) performed in a cross-over design.
24 h EE was measured at baseline (day 3) and at the end of each sleep
condition using a whole-room indirect calorimeter.
Results: Findings from this ongoing study support our hypothesis that
sleep restriction increases energy expenditure. Specifically, 24h EE was
significantly higher in the 5h than in the 9h condition (118±39.9 kcal/
day, p