What’s Sleep Got to do with Diabetes?
By now, we’ve all heard that most adults need 7 to 8 hours of sleep each night, and babies and teenagers need much more. But it’s not so common knowledge that lack of sleep has been linked to everything from increased risk of catching a cold to more deadly disorders, like diabetes, dementia, depression, obesity, heart attack, and stroke.
Lack of sleep is linked to diabetes because it impacts the body’s response to insulin, also referred to as “insulin sensitivity.” “Insulin sensitivity” is how well muscles and fat in the body are able to absorb sugar from our bloodstream to use for energy. Decreased insulin sensitivity—or, insulin resistance—means there are higher levels of sugar in the blood, which can be toxic over time. A small study recently showed that even with just short-term sleep deprivation (4 hours of sleep or less for 5 nights in a row), insulin sensitivity decreased – fat and muscle cells throughout the body were less sensitive to insulin and therefore left more sugar in the bloodstream.1 You can imagine that with habitual lack of sleep, insulin resistance becomes routine and might even get worse, leaving excess sugar in the bloodstream to wreak havoc on organs and nerves. Other researchers found similar results, suggesting that the impairment of insulin sensitivity caused by sleep deprivation can eventually lead to the development of diabetes.2 In a study of Japanese participants, young and middle-aged adults with inadequate sleep were more likely to have diabetes than those who slept longer (older adults didn’t have this association—suggesting sleep is extra important for those who are younger)3.
Other studies have shown that persistent lack of sleep is associated with obesity—those who slept for less time had higher rates of obesity. We already know that obesity can predispose a person to metabolic disorders like diabetes. Practically speaking, fewer hours of sleep translates into longer hours awake, which means more time available for eating. You may have eaten breakfast, lunch, and dinner, but with more wakeful hours after dinner, there are more opportunities for snacking. Also, fatigue from lack of sleep can drive hunger signals to compensate for lack of energy. When you are well rested from sleep, you are more energetic and less inclined to turn to food for energy.
Incidentally, too much sleep has also been tied to increased risk for diabetes, though it is unclear which comes first, the over sleeping or the diabetes. Studies show the relationship between sleep and type 2 diabetes risk is represented by a U-shaped curve—that is, people who sleep very much or very little are both more likely to develop diabetes. Sleeping for the sweet spot of 7-8 hours puts you at the lowest risk, but sleeping more or less puts you at higher risk.4 This doesn’t necessarily mean that sleeping fewer hours or sleeping in excess of 8 hours gives you diabetes. We’re not sure yet if the diabetes risk is a direct result of sleep duration or if it’s a byproduct of other behaviors that these people might share.
With all lifestyle-related diseases, many factors contribute to their onset and progression. Sleep is just one piece of the puzzle. Diet choices and exercise patterns, genetics, and the environment all contribute to our health. But if you’re fighting to keep your eyes open at your desk, getting a few more hours (or minutes) of shut-eye will do your body good.
Do you live with any sleep disorders (eg. insomnia, sleep apnea, RLS) in addition to your diabetes?