Rodrigo Chamorro1, Britta Wilms2, Annika Holst3, Clara Röhl3, Matthias Mölle4, Armin Knaak3, Svenja Meyhöfer2, Hendrik Lehnert5, Sebastian M Schmid6. 1. Institute for Endocrinology and Diabetes, University of Lübeck, Lübeck, Germany; Department of Nutrition, University of Chile, Santiago, Chile. 2. Institute for Endocrinology and Diabetes, University of Lübeck, Lübeck, Germany; German Center for Diabetes Research, München-Neuherberg, Germany. 3. Institute for Endocrinology and Diabetes, University of Lübeck, Lübeck, Germany. 4. Center of Brain, Behavior & Metabolism, University of Lübeck, Lübeck, Germany. 5. Institute for Endocrinology and Diabetes, University of Lübeck, Lübeck, Germany; University of Salzburg, Salzburg, Austria. 6. Institute for Endocrinology and Diabetes, University of Lübeck, Lübeck, Germany; German Center for Diabetes Research, München-Neuherberg, Germany. Electronic address: sebastian.schmid@uni-luebeck.de.
Abstract
OBJECTIVE: We evaluated the effect of acute mild light exposure at night on sleep architecture and glucose homeostasis. PATIENTS/ METHODS:Twenty healthy normal-weight men took part in two conditions of a randomized, controlled, balanced cross-over experimental study: i) two-consecutive nights with 8-h of sleep under dLAN (<5 lux) or ii) total darkness (CON). Sleep was evaluated by polysomnography. In the morning following 'night2', glucose homeostasis was assessed by an intravenous glucose tolerance test (ivGTT) with consecutive measures of glucose, insulin, and c-peptide. Plasma cortisol was measured at night before sleep, after morning awakening, and during mid-afternoon hours. RESULTS: There was no significant difference in total sleep time, sleep efficiency, and sleep latency between conditions (all p > 0.66). However, NREM sleep stage N3 latency was prolonged after dLAN (p = 0.02) and NREM sleep stage 2 was decreased after two nights with dLAN (p = 0.04). During the first sleep hour, power in slow-oscillations, slow-waves, and delta bands diminished after dLAN (all p < 0.04). Glucose, insulin, and c-peptide were not altered by dLAN (all p > 0.14). Cortisol was reduced in the afternoon after 'night1' and in the morning after 'night2' (both p < 0.03). CONCLUSIONS: dLAN slightly disturbed sleep architecture and quality without impairment of glucose homeostasis. Longer exposure to chronic dLAN might be needed to unmask its hypothesized metabolic consequences.
RCT Entities:
OBJECTIVE: We evaluated the effect of acute mild light exposure at night on sleep architecture and glucose homeostasis. PATIENTS/ METHODS: Twenty healthy normal-weight men took part in two conditions of a randomized, controlled, balanced cross-over experimental study: i) two-consecutive nights with 8-h of sleep under dLAN (<5 lux) or ii) total darkness (CON). Sleep was evaluated by polysomnography. In the morning following 'night2', glucose homeostasis was assessed by an intravenous glucose tolerance test (ivGTT) with consecutive measures of glucose, insulin, and c-peptide. Plasma cortisol was measured at night before sleep, after morning awakening, and during mid-afternoon hours. RESULTS: There was no significant difference in total sleep time, sleep efficiency, and sleep latency between conditions (all p > 0.66). However, NREM sleep stage N3 latency was prolonged after dLAN (p = 0.02) and NREM sleep stage 2 was decreased after two nights with dLAN (p = 0.04). During the first sleep hour, power in slow-oscillations, slow-waves, and delta bands diminished after dLAN (all p < 0.04). Glucose, insulin, and c-peptide were not altered by dLAN (all p > 0.14). Cortisol was reduced in the afternoon after 'night1' and in the morning after 'night2' (both p < 0.03). CONCLUSIONS: dLAN slightly disturbed sleep architecture and quality without impairment of glucose homeostasis. Longer exposure to chronic dLAN might be needed to unmask its hypothesized metabolic consequences.