Spiegel · Lancet (London, England) 1999 · Within-subject controlled interventional trial · n=11

Impact of sleep debt on metabolic and endocrine function.

Cited 3691 times in the scientific literature.

Level 3 - non-randomized controlled study

Non-randomized within-subject controlled trial in humans

PubMed 10543671 · doi:10.1016/S0140-6736(99)01376-8 · record verified 2026-08-31

What was done

Carbohydrate metabolism, thyrotropic function, hypothalamic-pituitary-adrenal axis activity, and sympathovagal balance were assessed in 11 young men after 6 nights of sleep restriction (4 hours in bed per night). Measurements were compared against values obtained after a subsequent 6-night sleep-recovery period (12 hours in bed per night).

What was found

Glucose tolerance was significantly lower in the sleep-debt condition compared with the sleep-recovery condition (p<0.02). Thyrotropin concentrations were also lower (p<0.01). Evening cortisol concentrations were elevated (p=0.0001), and sympathetic nervous system activity increased (p<0.02). The abstract provides p-values and directions of change but does not report baseline values, absolute effect sizes, or confidence intervals.

Why it matters

This study provides experimental human evidence that short-term sleep restriction impairs metabolic and endocrine regulation, producing changes comparable to those seen in aging.

Limits

The study included only 11 participants, all of whom were young men, limiting generalizability to women, older demographics, or people with baseline metabolic conditions. The protocol order was not randomized or counterbalanced in the abstract, and absolute quantitative measurements are omitted.

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