Diabetes and sleep

Sleep has often been thought of as a “restorative” process for the mind and the body; however, it has been shown that it also directly affects many metabolic and hormonal processes. Sleep which is a key factor in physiological restitution also modulates the metabolic, endocrine, and cardiovascular systems and thus has medical implications which include decreased glucose tolerance and insulin sensitivity. Reduction in the time available for sleep is a hallmark of modern society which has developed during the past few decades with increase in the time available for work and leisure, often viewed as harmless and efficient. In normal, healthy individuals, glucose tolerance varies across the day, with total sleep loss or even a 2-h reduction of sleep/night for 1 week there is increased levels of proinflammatory cytokines and low grade inflammation, a condition known to predispose to insulin resistance and diabetes. Sleep deprivation is associated with disturbances in the secretion of the counter regulatory hormones such as growth hormone and cortisol. Elevated evening cortisol levels can lead to morning insulin resistance, while the sympathetic nervous system inhibits insulin release while the parasympathetic system stimulates it, thus leading to elevated glucose levels. Adults are sleeping less and less in our society. Yet sleep is no longer thought of as strictly a restorative process for the body. The importance of sleep for metabolic function and specifically glucose homeostasis is now widely accepted, as many studies have shown a correlation between sleep deprivation or poor sleep quality and an increased risk of diabetes.