Sleep restriction increases free fatty acids in healthy men

Diabetologia. 2015 Apr;58(4):791-8. doi: 10.1007/s00125-015-3500-4. Epub 2015 Feb 22.


Aims/hypothesis: Sleep loss is associated with insulin resistance and an increased risk for type 2 diabetes, yet underlying mechanisms are not understood. Elevation of circulating non-esterified (i.e. free) fatty acid (NEFA) concentrations can lead to insulin resistance and plays a central role in the development of metabolic diseases. Circulating NEFA in healthy individuals shows a marked diurnal variation with maximum levels occurring at night, yet the impact of sleep loss on NEFA levels across the 24 h cycle remains unknown. We hypothesised that sleep restriction would alter hormones that are known to stimulate lipolysis and lead to an increase in NEFA levels.

Methods: We studied 19 healthy young men under controlled laboratory conditions with four consecutive nights of 8.5 h in bed (normal sleep) and 4.5 h in bed (sleep restriction) in randomised order. The 24 h blood profiles of NEFA, growth hormone (GH), noradrenaline (norepinephrine), cortisol, glucose and insulin were simultaneously assessed. Insulin sensitivity was estimated by a frequently sampled intravenous glucose tolerance test.

Results: Sleep restriction relative to normal sleep resulted in increased NEFA levels during the nocturnal and early-morning hours. The elevation in NEFA was related to prolonged nocturnal GH secretion and higher early-morning noradrenaline levels. Insulin sensitivity was decreased after sleep restriction and the reduction in insulin sensitivity was correlated with the increase in nocturnal NEFA levels.

Conclusions/interpretation: Sleep restriction in healthy men results in increased nocturnal and early-morning NEFA levels, which may partly contribute to insulin resistance and the elevated diabetes risk associated with sleep loss.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Biomarkers / blood
  • Blood Glucose / metabolism
  • Circadian Rhythm*
  • Fatty Acids, Nonesterified / blood*
  • Healthy Volunteers
  • Human Growth Hormone / blood
  • Humans
  • Hydrocortisone / blood
  • Insulin / blood
  • Insulin Resistance
  • Male
  • Norepinephrine / blood
  • Random Allocation
  • Sleep Deprivation / blood*
  • Sleep Deprivation / physiopathology
  • Sleep*
  • Time Factors
  • Up-Regulation
  • Young Adult


  • Biomarkers
  • Blood Glucose
  • Fatty Acids, Nonesterified
  • Insulin
  • Human Growth Hormone
  • Hydrocortisone
  • Norepinephrine