1. Introduction
obesity, metabolic impairments, Sleep loss, sleep loss, ’ appetite
METABOLIC DISEASES, OBESITY, TYPE 2 DIABETES, ADVERSE EFFECTS
These authors contributed equally to this work.Objective: There is evidence that reduced sleep duration increases hunger, appetite, and food intake, leading to metabolic diseases, such as type 2 diabetes and obesity. However, the impact of sleep timing, irrespective of its duration and on the regulation of hunger and appetite, is less clear. We aimed to evaluate the impact of sleep loss during the late vs. early part of the night on the regulation of hunger, appetite, and desire for food. Methods: Fifteen normal-weight ([mean ± SEM] body-mass index: 23.3 ± 0.4 kg/mSleep loss has become common in modern societies [Most experimental studies have shown that acute sleep loss increases ghrelin and decreases leptin concentrations, as relevant orexigenic and anorexigenic hormonal mediators of hunger and appetite, respectively. In line, short sleep was accompanied by increased feelings of hunger and appetite, as well as caloric intake [The mechanisms linking short sleep to acute changes in feelings of hunger and, thus, shift in the energy balance are under investigation. Elevated ghrelin concentrations might mediate increased food intake, and some, but not all, studies report increased ghrelin concentrations after shortened sleep [Regarding the desire to eat after short sleep, some studies report no changes in perceived pleasantness of food or the desire to eat after one night with reduced sleep of 4 h and after five consecutive days of insufficient sleep, mimicking a work week, respectively [The impact of sleep timing, irrespective of its duration and on the regulation of hunger and appetite, is less clear. Alterations in the timing of sleep during restricted sleep could result in dissimilar sleep and metabolic impairments, given the notorious influence of sleep on metabolic processes [We have previously shown that the timing of sleep loss is relevant for glucose homeostasis and physical activity patterns in healthy humans. Sleep loss, with advanced awakening time, led to reduced glucagon and altered cortisol levels [The present study investigated the impact of the specific timing of sleep loss compared to regular sleep on appetite regulation and desire for foods. We hypothesized that both short sleep duration per se and the timing of sleep loss, i.e., early night sleep loss vs. late night sleep loss, may modulate the adverse effects of sleep loss on humans’ appetite regulation, feelings of hunger, and desire for food.