In this study, we assessed the effects of a single night of partial sleep restriction on insulin sensitivity in patients with type 1 diabetes. The results indicate that a single night of partial sleep restriction reduces insulin sensitivity of insulin-stimulated glucose uptake by 14–21%. Partial sleep restriction did not significantly affect basal glucose metabolism. We conclude that sleep duration is a determinant of peripheral insulin sensitivity in patients with type 1 diabetes.
In the current study we included the data of only seven patients with type 1 diabetes. The strictly controlled design of this pathophysiological study in combination with the fact that each subject served as his/her own control enabled us to establish subtle effects of partial sleep deprivation on parameters of insulin sensitivity. Nonetheless, larger numbers of subjects are required to assess the involvement of relevant patient characteristics such as sex, age, and antecedent glucoregulation on the effects of sleep restriction on insulin sensitivity.
This is the first study that documents an adverse effect of partial sleep restriction on insulin sensitivity in patients with type 1 diabetes. In healthy subjects, sleep restriction induces insulin resistance and reduces glucose tolerance (7
). By analogy, it can be expected that sleep restriction increases postprandial glucose levels in patients with type 1 diabetes in the absence of concurrent adaptations of the dose of exogenous insulin.
Insulin sensitivity is not static but varies over time within individuals. This is also reflected by the current study in patients with type 1 diabetes. Several epidemiological studies documented an association between chronic partial sleep restriction and development of insulin resistance and type 2 diabetes (5
). Therefore, exposure to chronic sleep restriction might contribute to insulin resistance in patients with type 1 diabetes. In turn, insulin resistance is associated with an increased risk for microvascular and macrovascular complications in type 1 diabetes (18
Unfortunately, the current study was not designed to elucidate the mechanisms involved in the induction of insulin resistance by partial sleep deprivation. A single night of partial sleep restriction to 4.5 h does not cause endocrine changes that simply explain the induction of insulin resistance (19
). Subsequent nights of partial sleep deprivation induce subtle changes in cortisol and catecholamine secretion (7
). However, the relations between these effects of sleep deprivation on endocrine homeostasis and glucose tolerance are uncertain. Partial sleep deprivation for a single and subsequent nights increased the sympathetic tone based on recordings of heart rate variability after sleep deprivation (21
). However, the relationship between elevated sympathovagal balance at the level of the heart and the sympathetic outflow to liver, muscles, and adipose tissue is uncertain (21
Interestingly, in addition to sleep duration, the composition of sleep in terms of sleep stages is also a determinant of insulin sensitivity. Selective suppression of slow-wave sleep, without a change in total sleep duration, decreased glucose tolerance in healthy subjects (23
). The differential effects of altered sleep composition versus decreased total sleep duration on insulin sensitivity awaits further study.
Data on sleep physiology and sleep disturbances in patients with type 1 diabetes are rare. Jauch-Chara et al. (24
) reported alterations in neuroendocrine sleep architecture and a trend toward less slow-wave sleep in 14 patients with type 1 diabetes. Children with type 1 diabetes have a more disrupted sleep than healthy children (25
). If type 1 diabetes indeed causes disruption of sleep patterns, this may in turn impair glucose regulation, creating a vicious circle.
In conclusion, the present study indicates that partial sleep restriction decreases insulin sensitivity of insulin-mediated glucose uptake in patients with type 1 diabetes. It is important to further assess the relationship between sleep physiology and glucoregulation in patients with type 1 diabetes. Sleep duration might become another therapeutic target to improve glucoregulation in type 1 diabetes.