Impairments in glycaemic control do not increase linearly with repeated nights of sleep restriction in healthy adults: a randomized controlled trial

Evidence suggests reduced glycaemic control following sleep restriction in healthy individuals. However, it remains unknown if impairments in glycaemic control increase with each additional night of sleep restriction in a linear manner. This randomised crossover study aimed to determine if the impairment in glycaemic control increases with each additional night of sleep restriction. Ten healthy individuals underwent four nights of control sleep (eight hours in bed) and four nights of sleep restriction (four hours in bed) in a sleep laboratory. An oral glucose tolerance test was conducted each morning. Serum glucose and insulin were measured. Glucose and insulin area under the curve were higher overall in the sleep restriction trial compared to control (p < 0.001 and p = 0.033), however no effect of day (p = 0.620 and p = 0.863) or interaction effect (p = 0.152 and p = 0.285) were observed. This supports previous literature showing a detrimental impact of sleep restriction on glucose regulation. The present findings, however, suggest the impairment in glycaemic control does not increase in a linear manner with an increasing number of nights of sleep restriction. This may have implications for the design of future studies examining sleep restriction and glycaemic control. Novelty Bullets: -Four nights of sleep restriction impaired glycaemic control in healthy individuals, but did not do so in a linear manner. -No effect of number of nights of restriction was found for glucose or insulin, which may have implications for future studies.