Context and purpose: The literature suggests that severe sleep loss of more than a few hours a night decreases glucose tolerance and insulin sensitivity. The aim of this study was to determine whether moderate sleep restriction had similar effects.
Methods: Fifteen healthy non-obese (BMI=24.5±3.4 kg/m2) young adults (20.6±1.3 years) completed two 2-hour oral glucose tolerance tests (OGTT): one was after 3 days of time-in-bed restriction by 1-3 hours each night, and the other was after 3 days of ad libitum sleep. Glucose and insulin concentrations during OGTT, and fasting glucagon and cortisol concentrations were determined. The homeostasis model of insulin resistance (HOMA-IR), Matsuda index, and the quantitative insulin sensitivity check index (QUICKI) were calculated.
Results: The total time-in-bed during the sleep restriction and the ad libitum phase was 5.98±0.76 and 7.98±0.54 hours/day, and total sleep time was 5.16±0.49 and 6.65±0.64 hours/day, respectively. Glucose concentrations before and 30, 60, 90, and 120 minutes following consumption of glucose and area under the curve were not different for the two OGTT (p > 0.10 for all). Insulin concentration at fasting and area under the curve during the OGTT were significantly higher (p = 0.034 and 0.038, respectively) following restricted sleep than following ad libitum sleep. Fasting glucagon concentration was also higher (p = 0.003). The HOMA-IR, Matsuda index, and QUICKI all suggested decreased insulin sensitivity following restricted sleep.
Conclusion: Short-term moderate sleep restriction reduced insulin sensitivity compared to ad libitum sleep in this group of healthy young adults.
Keywords: chronic; glucose tolerance; insulin sensitivity; sleep duration.