Short-term sleep loss decreases physical activity under free-living conditions but does not increase food intake under time-deprived laboratory conditions in healthy men.
BACKGROUND
Short sleep duration is correlated with an increased risk of developing obesity and cardiovascular disease, but the mechanisms behind this relation are largely unknown.


OBJECTIVE
We aimed to test the hypothesis that acute sleep loss decreases physical activity while increasing food intake, thereby shifting 2 crucial behavioral components of energy homeostasis toward weight gain.


METHODS
In 15 healthy, normal-weight men, spontaneous physical activity was registered by accelerometry during the entire experiment, and food intake as well as relevant hormones were assessed during a 15-h daytime period after 2 nights of regular sleep (bed time: 2245-0700) and after 2 nights of restricted sleep (bed time: 0245-0700). Experiments were performed in a crossover design.


RESULTS
Sleep restriction significantly decreased physical activity during the daytime spent under free-living conditions after the first night of sleep manipulation (P = 0.008). Also, intensities of physical activity were shifted toward lower levels, with less time spent with intense activities (P = 0.046). Total energy intake, feelings of hunger, and appetite as well as ghrelin and leptin concentrations during day 2 remained unaffected by acute sleep restriction.


CONCLUSIONS
In contrast to our expectation, short-term sleep loss neither increased food intake nor affected concentrations of the hunger-regulating hormones leptin and ghrelin. However, the observed decrease in daytime physical activity may point to another potentially important behavioral mechanism for the health-impairing influence of sleep loss.
Departments of Internal Medicine I, the University of Luebeck, Luebeck, Germany.
Sebastian M
SM
Schmid
Manfred
M
Hallschmid
Kamila
K
Jauch-Chara
Britta
B
Wilms
Christian
C
Benedict
Hendrik
H
Lehnert
Jan
J
Born
Bernd
B
Schultes
D000328:Adult; D001066:Appetite; D018592:Cross-Over Studies; D004435:Eating; D054439:Ghrelin / Q000097:blood; D006801:Humans; D006815:Hunger; D020738:Leptin / Q000097:blood; D008297:Male; D009043:Motor Activity; D012528:Satiety Response; D012890:Sleep
D054439:Ghrelin; D020738:Leptin