RESUMO
BACKGROUND: Epidemiologic evidence indicates that chronic sleep curtailment increases risk of developing obesity, but the mechanisms behind this relation are largely unknown. OBJECTIVE: We examined the influence of a single night of total sleep deprivation on morning energy expenditures and food intakes in healthy humans. DESIGN: According to a balanced crossover design, we examined 14 normal-weight male subjects on 2 occasions during a regular 24-h sleep-wake cycle (including 8 h of nocturnal sleep) and a 24-h period of continuous wakefulness. On the morning after regular sleep and total sleep deprivation, resting and postprandial energy expenditures were assessed by indirect calorimetry, and the free-choice food intake from an opulent buffet was tested in the late afternoon at the end of the experiment. Circulating concentrations of ghrelin, leptin, norepinephrine, cortisol, thyreotropin, glucose, and insulin were repeatedly measured over the entire 24-h session. RESULTS: In comparison with normal sleep, resting and postprandial energy expenditures assessed on the subsequent morning were significantly reduced after sleep deprivation by ≈5% and 20%, respectively (P < 0.05 and P < 0.0001). Nocturnal wakefulness increased morning plasma ghrelin concentrations (P < 0.02) and nocturnal and daytime circulating concentrations of thyreotropin, cortisol, and norepinephrine (P < 0.05) as well as morning postprandial plasma glucose concentrations (P < 0.05). Changes in food intakes were variable, and no differences between wake and sleep conditions were detected. CONCLUSION: Our findings show that one night of sleep deprivation acutely reduces energy expenditure in healthy men, which suggests that sleep contributes to the acute regulation of daytime energy expenditure in humans.
