BACKGROUND:

Chronic sleep debt is becoming increasingly common and affects millions of people in more-developed countries. Sleep debt is currently believed to have no adverse effect on health. We investigated the effect of sleep debt on metabolic and endocrine functions.

METHODS:

We assessed carbohydrate metabolism, thyrotropic function, activity of the hypothalamo-pituitary-adrenal axis, and sympathovagal balance in 11 young men after time in bed had been restricted to 4 h per night for 6 nights. We compared the sleep-debt condition with measurements taken at the end of a sleep-recovery period when participants were allowed 12 h in bed per night for 6 nights.

FINDINGS:

Glucose tolerance was lower in the sleep-debt condition than in the fully rested condition (p<0.02), as were thyrotropin concentrations (p<0.01). Evening cortisol concentrations were raised (p=0.0001) and activity of the sympathetic nervous system was increased in the sleep-debt condition (p<0.02).

INTERPRETATION:

Sleep debt has a harmful impact on carbohydrate metabolism and endocrine function. The effects are similar to those seen in normal ageing and, therefore, sleep debt may increase the severity of age-related chronic disorders.