Sleep restriction for 1 week reduces insulin sensitivity in healthy men

Area of Science:

• Metabolic health and sleep science.
• Endocrinology and diabetes research.

Background:

• Short sleep duration is linked to impaired glucose tolerance and increased diabetes risk.
• The specific impact of sleep restriction on insulin sensitivity remains unclear.
• This study investigated how reduced sleep affects insulin sensitivity and explored potential interventions.

Purpose of the Study:

• To test the hypothesis that decreased nighttime sleep duration reduces insulin sensitivity.
• To assess the efficacy of modafinil in counteracting sleep restriction-induced changes in insulin sensitivity.
• To evaluate the effects of sleep restriction on glucose metabolism and related physiological markers.

Main Methods:

• A 12-day inpatient study involving 20 healthy men (aged 20-35, BMI 20-30 kg/m²).
• Sleep conditions included a sleep-replete phase (≥8 nights, 10 h/night) and a sleep-restricted phase (7 nights, 5 h/night).
• Glucose metabolism was assessed using intravenous glucose tolerance tests (IVGTT) and euglycemic-hyperinsulinemic clamps; modafinil or placebo was administered during sleep restriction.

Main Results:

• Sleep restriction significantly reduced insulin sensitivity by 20% (IVGTT) and 11% (clamp) (P < 0.001 and P < 0.04, respectively).
• Glucose tolerance and the disposition index were also reduced by sleep restriction.
• Modafinil treatment did not alter the negative effects of sleep restriction on insulin sensitivity, glucose metabolism, or related hormonal and neurobehavioral measures.

Conclusions:

• One week of sleep restriction (5 h/night) markedly reduces insulin sensitivity in healthy men.
• These findings raise concerns about the long-term health implications of chronic insufficient sleep, particularly regarding insulin resistance and associated diseases.
• Modafinil does not appear to mitigate the adverse metabolic effects of acute sleep restriction.