by Tenebris

Created on: November 18, 2009

Strong correlational links between poor sleep and type 2 diabetes have been observed for decades. A 2005 study shows a clear link between endocrine risk factors for type 2 diabetes and inadequate sleep. Even in healthy people, increasing sleep debt is linked with impaired glucose tolerance. But which came first: the poor sleep or the diabetes? Or is something else under the surface influencing both?

We now know that poor quality sleep almost always results in insulin resistance. In a 2008 study, nine healthy volunteers were awoken with a loud noise whenever they drifted into deep sleep. Their overall amount of sleep, as measured before the experiment, was left the same as before. After just three nights of this, eight of the nine volunteers developed insulin resistance.

Other studies have verified that poor sleep impairs glucose tolerance regardless of whether sleep was reduced in quality or simply cut short. A 2009 systemic review and meta-analysis which examined every previous prospective study which had a follow-up of at least three years found that quantity and quality of sleep consistently and significantly predict the risk of the development of type 2 diabetes.

For diabetics who are already suffering from at least one complication of diabetes, such as kidney damage or diabetic retinopathy, the effects of sleep debt and poor sleep quality are magnified.

Not only can poor quality sleep lead to diabetes, it may also be a consequence of diabetes. Many diabetics suffer from overnight blood sugar lows, which in turn impact on the quality of sleep. The feeling of a sugar low can awaken some diabetics. Others sleep right through it, but not well. Because morning blood sugar levels look normal, diabetics may never even be aware of the overnight low, except that they wake up tired and groggy. This can easily become a vicious circle.

To avoid overnight lows, some diabetics eat a light meal an hour or two before bedtime. Those who use insulin time this meal for just after the evening insulin. The meal has to be very light, lest the diabetic risk an overnight high, which is just as disruptive to sleep. This method does not work for all diabetics, however, and some may find it counterproductive.

Several conditions which result in poor quality sleep have independently been linked with type 2 diabetes, from sleep apnea to irregular work schedules to outright insomnia. Many of these conditions are also linked with obesity, resulting in a perfect storm of diabetes risk factors.

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