Poor sleep quality and sleep apnea are associated with higher resting energy expenditure in obese individuals with short sleep duration.
BACKGROUND
Epidemiological studies reported an inverse or U-shaped relationship between sleep duration and weight. The relationship between sleep and resting energy expenditure (REE) has not been well characterized.


OBJECTIVE
The aim of the study was to determine the relationship between sleep, REE, and stress hormones.


METHODS
We conducted a cross-sectional evaluation of a prospective cohort study at a tertiary referral research clinical center.


METHODS
Subjects included 126 obese individuals (30 males, 96 females; age, 40.5 ± 6.9 yr; body mass index, 38.6 ± 6.5 kg/m(2); sleep duration, 360 ± 50 min/night; and sleep efficiency, 79.5 ± 7.5%).


METHODS
REE and respiratory quotient (RQ) were assessed by indirect calorimetry. Sleep duration and sleep efficiency were assessed by actigraphy. Sleep quality was estimated by questionnaires, and sleep apnea was evaluated by respiratory disturbance index (RDI). Morning plasma ACTH, serum cortisol, and 24-h urinary free cortisol and catecholamines were also measured.


RESULTS
RDI was positively correlated with REE adjusted by fat-free mass (r = 0.307; P = 0.003) and RQ (r = 0.377; P < 0.001). Sleep efficiency was inversely correlated with RQ (r = -0.200; P = 0.033). The relationship of RDI score and REE was stronger in men than women (P = 0.03). In women, serum cortisol was positively correlated (r = 0.407; P < 0.001), and Epworth sleepiness score tended to be inversely (r = -0.190; P = 0.086) correlated with adjusted REE. The RQ was positively related to RDI in women, whereas subjective sleep time was related to RQ in men. In a multiple regression model, RDI, serum cortisol, and urinary norepinephrine were directly related to REE, whereas serum cortisol also directly related to adjusted REE.


CONCLUSIONS
Poor sleep quality was associated with increased REE, a higher RQ indicating a shift from fat toward carbohydrate oxidation, and activation of the stress system.
Section on Neuroendocrinology of Obesity, Diabetes, Endocrinology, and Obesity Branch/National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892-2560, USA.
Lilian
L
de Jonge
Xiongce
X
Zhao
Megan S
MS
Mattingly
Samuel M
SM
Zuber
Paolo
P
Piaggi
Gyorgy
G
Csako
Giovanni
G
Cizza
D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D011446:Prospective Studies; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000378:metabolism*