Here's another reason to get a good night's sleep: Too little shut-eye plays havoc with your fat cells, which could lead to weight gain and type 2 diabetes, researchers reported.
Scientists have known for years that sleep deprivation makes you tired and cranky and less able to think clearly. It also can make you fat because it increases levels of a hunger hormone and decreases levels of a fullness hormone, which could lead to overeating and weight gain.
The latest study indicates that not getting enough sleep reduces your fat cells' ability to respond properly to the hormone insulin, which is crucial for regulating energy storage and use. Over time the disruption could lead to weight gain, type 2 diabetes and other health problems, the researchers say.
"Our fat cells need sleep to function properly," says Matthew Brady, one of the study's authors and vice chair of the committee on Molecular Metabolism and Nutrition at the University of Chicago. "If you're sleep deprived, your brain may feel groggy, and it turns out that your fat cells also need sleep or they are metabolically groggy." The findings reported in Tuesday's issue of the Annals of Internal Medicine showed that after four nights of sleep deprivation, the body's overall ability to respond to insulin properly decreased by an average of 16%, which is the first step toward developing type 2 diabetes, Brady says.
After too little sleep, the fat cells' ability to use insulin properly, called insulin sensitivity, dropped by 30%. When fat cells don't respond to insulin properly, lipids (fats) circulate in the blood, which can lead to other health problems, including type 2 diabetes, Brady says.
People think of fat as a bad guy, but some fat "is your friend," Brady says. "When fat cells are functioning properly, they safely store fat away for future use such as when you are sleeping or exercising. Fat cells remove fatty acids and lipids from circulating in the body and damaging other tissues. But when your fat cells stop responding to insulin properly, then lipids leave the fat cells and leach out into your blood." That allows lipids to accumulate in other tissues, such as the liver, he says.
Insulin also plays an important role in the release of the hormone leptin, which is involved in making people feel full. "Insulin promotes release of leptin, so if your fat cells are less insulin-sensitive, you will make less leptin, which is associated with an increase in food consumption and weight gain," Brady says. Leptin is released by the fat cells and tells the brain about the energy balance of the body. Low leptin levels tell your body it's starving and increase your appetite, she says.
The kind of sleep deprivation experienced by the participants in the study happens in the "real world" when people are cramming for finals, have a newborn in the house or have a lot of extra work for their job, Brady says. "A lot of people have had stretches where they have only been able to get three or four hours of sleep a night."
Brady recommends aiming for eight hours of sleep a night. "It's very important for not only your brain but likely the rest of your body."
Discover other critical roles of sleep here.
Reference: Sleeptest.com November Newsletter - Adapted from an article by Nanci Hellmich, USA TODAY