Proceedings of The Physiological Society

Sleep Sleep and Circadian Rhythms (London, UK) (2018) Proc Physiol Soc 42, C18

Poster Communications

The impairment in insulin sensitivity after sleep restriction does not increase with more nights of sleep restriction.

E. Sweeney1, D. J. Peart1, J. G. Ellis2, I. H. Walshe1

1. Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle Upon Tyne, United Kingdom. 2. Northumbria Sleep Research Laboratory, Northumbria University, Newcastle Upon Tyne, United Kingdom.

Voluntary sleep curtailment is common in modern society and has been linked to poor glucose control. Many experimental studies have shown impaired glucose regulation after sleep restriction, ranging from one to five nights. However, it remains unclear whether the impairment in glucose regulation is related to the number of nights of sleep restriction, as methodological differences make comparisons between existing studies difficult. The current study aimed to explore glucose regulation following each night of sleep restriction for four consecutive nights to identify if there is a linear effect of number of nights of restriction on the impairment in glucose regulation. We hypothesised that the level of glucose control would decline with each subsequent night of sleep restriction. 10 healthy, non-diabetic humans aged between 18 and 50 years were recruited for this randomised crossover study with 4 nights of control sleep (8 h/night) and 4 nights of sleep restriction (4 h/night), separated by a 3 wk washout period. Participants stayed in the laboratory overnight but were permitted to leave during the day, during which time wrist actigraphy was used to ensure no sleep or physical activity was undertaken. Each morning upon wakening an oral glucose tolerance test was conducted and venous blood samples were collected at regular intervals for 120 min. Glucose and insulin concentrations were determined from the blood samples and area under the curve (AUC) was calculated for each day using the trapezoidal rule. ANOVAs were conducted to compare glucose and insulin AUC for the four days in each condition. Glucose AUC displayed trends for an effect of trial (P = 0.063) and interaction effect (P = 0.098) but no effect of day (P = 0.773). Insulin AUC showed a significant effect of trial (P = 0.020), however there was no effect of day (P = 0.861) or interaction effect (P = 0.129). Our findings agree with previous studies which have shown that sleep restriction impairs glucose regulation. However, contrary to our hypothesis, there does not appear to be a significant linear effect of impairment with an increasing number of nights of sleep restriction.

Where applicable, experiments conform with Society ethical requirements