title: Evening chronotype is associated with changes in eating behavior, more sleep apnea, and increased stress hormones in short sleeping obese individuals.
abstract: BACKGROUND
  Short sleep duration and decreased sleep quality are emerging risk factors for obesity and its associated morbidities. Chronotype, an attribute that reflects individual preferences in the timing of sleep and other behaviors, is a continuum from morningness to eveningness. The importance of chronotype in relation to obesity is mostly unknown. Evening types tend to have unhealthy eating habits and suffer from psychological problems more frequently than Morning types, thus we hypothesized that eveningness may affect health parameters in a cohort of obese individuals reporting sleeping less than 6.5 hours per night.
  
  
  RESULTS
  BASELINE DATA FROM OBESE (BMI: 38.5±6.4 kg/m(2)) and short sleeping (5.8±0.8 h/night by actigraphy) participants (n = 119) of the Sleep Extension Study were analyzed (www.ClinicalTrials.gov, identifier NCT00261898). Assessments included the Horne and Ostberg Morningness-Eveningness questionnaire, a three-day dietary intake diary, a 14-day sleep diary, 14 days of actigraphy, and measurements of sleep apnea. Twenty-four hour urinary free cortisol, 24 h urinary norepinephrine and epinephrine levels, morning plasma ACTH and serum cortisol, fasting glucose and insulin, and lipid parameters were determined. Eveningness was associated with eating later in the day on both working and non-working days. Progression towards eveningness was associated with an increase in BMI, resting heart rate, food portion size, and a decrease in the number of eating occasions and HDL-cholesterol. Evening types had overtly higher 24 h urinary epinephrine and morning plasma ACTH levels, and higher morning resting heart rate than Morning types. In addition, Evening types more often had sleep apnea, independent of BMI or neck circumference.
  
  
  CONCLUSIONS
  Eveningness was associated with eating later and a tendency towards fewer and larger meals and lower HDL-cholesterol levels. In addition, Evening types had more sleep apnea and higher stress hormones. Thus, eveningness in obese, chronically sleep-deprived individuals compounds the cardiovascular risk associated with obesity.
authors.affiliation: Clinical Center, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Eliane A
authors.initials: EA
authors.lastname: Lucassen
authors.forename: Xiongce
authors.initials: X
authors.lastname: Zhao
authors.forename: Kristina I
authors.initials: KI
authors.lastname: Rother
authors.forename: Megan S
authors.initials: MS
authors.lastname: Mattingly
authors.forename: Amber B
authors.initials: AB
authors.lastname: Courville
authors.forename: Lilian
authors.initials: L
authors.lastname: de Jonge
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Csako
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cizza
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000886:Anthropometry; D002940:Circadian Rhythm / Q000502:physiology*; D003710:Demography; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D006339:Heart Rate; D006728:Hormones / Q000097:blood* / Q000652:urine; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008954:Models, Biological; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood / Q000150:complications / Q000503:physiopathology* / Q000652:urine; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000097:blood / Q000150:complications / Q000503:physiopathology* / Q000652:urine; D013315:Stress, Psychological / Q000097:blood* / Q000652:urine; D013997:Time Factors
chemical_list: D006728:Hormones; D008055:Lipids; D000324:Adrenocorticotropic Hormone