title: Energy metabolism differs between sleep stages and begins to increase prior to awakening.
abstract: Human sleep is generally consolidated into a single prolonged period, and its metabolic consequence is to impose an extended period of fasting. Changes in sleep stage and homeostatic sleep drive following sleep onset may affect sleeping metabolic rate through cross talk between the mechanisms controlling energy metabolism and sleep. The purpose of this study was to isolate the effects of sleep stage and time after sleep onset on sleeping metabolic rate.
  
  
  
  The sleeping metabolic rate of 29 healthy adults was measured using whole room indirect calorimetry, during which polysomnographic recording of sleep was performed. The effects of sleep stage and time after sleep onset on sleeping metabolic rate were evaluated using a semi-parametric regression analysis. A parametric analysis was used for the effect of sleep stage and a non-parametric analysis was used for the effect of time.
  
  
  
  Energy expenditure differed significantly between sleep stages: wake after sleep onset (WASO)>stage 2, slow wave sleep (SWS), and REM; stage 1>stage 2 and SWS; and REM>SWS. Similarly, carbohydrate oxidation differed significantly between sleep stages: WASO > stage 2 and SWS; and stage 1>SWS. Energy expenditure and carbohydrate oxidation decreased during the first half of sleep followed by an increase during the second half of sleep.
  
  
  
  This study identified characteristic phenotypes in energy expenditure and carbohydrate oxidation indicating that sleeping metabolic rate differs between sleep stages.
authors.affiliation: International Institute for Integrative Sleep Medicine, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8575, Ibaraki, Japan.
authors.forename: Momoko
authors.initials: M
authors.lastname: Kayaba
authors.affiliation: Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan.
authors.forename: Insung
authors.initials: I
authors.lastname: Park
authors.affiliation: Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sports Science, Japan Institute of Sports Sciences, Kita, 115-0056, Tokyo, Japan.
authors.forename: Kaito
authors.initials: K
authors.lastname: Iwayama
authors.affiliation: International Institute for Integrative Sleep Medicine, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8575, Ibaraki, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Seya
authors.affiliation: Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Ogata
authors.affiliation: Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan; Department of Administrative Nutrition, Faculty of Health and Nutrition, Tokyo Seiei College, Katsushika, 124-8530, Tokyo, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yajima
authors.affiliation: International Institute for Integrative Sleep Medicine, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8575, Ibaraki, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Satoh
authors.affiliation: International Institute for Integrative Sleep Medicine, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8575, Ibaraki, Japan; Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan. Electronic address: tokuyama@taiiku.tsukuba.ac.jp.
authors.forename: Kumpei
authors.initials: K
authors.lastname: Tokuyama
mesh_terms: D000328:Adult; D044466:Asian People; D001823:Body Composition / Q000502:physiology; D002153:Calorimetry, Indirect; D050260:Carbohydrate Metabolism / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D017286:Polysomnography; D012890:Sleep / Q000502:physiology; D012894:Sleep Stages / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult
keywords: Metabolic chamber; Semi-parametric regression; Sleep stage; Sleeping metabolic rate; Time after sleep onset