Good night, fat cells: Sleep matters
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, according to new research.
Scientists have known for years that sleep deprivation makes you tired and cranky and less able to think clearly. It can also make you fat, because it increases levels of a hunger hormone and decreases levels of a fullness hormone, which may lead to overeating and weight gain.
The latest study indicates that not getting enough shut-eye reduces your fat cells' ability to respond properly to the hormone insulin, which is critical for regulating energy storage and use. Over time, this disruption could lead to weight gain, 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."
Brady and colleagues had seven healthy, lean young adults live in a sleep laboratory for four days on two separate occasions -- spaced four weeks apart. Participants were fed identical meals for the eight days.
For one part of the study, the participants spent 8 hours in bed on four consecutive nights. They slept an average of about 7.87 hours a night. For the other part, they spent 4 hours in bed for four consecutive nights, sleeping an average of 4.35 hours.
After the fourth night under each condition, researchers measured participants' overall response to insulin and collected abdominal fat tissue from the participants to measure how the fat cells reacted to insulin after sleep deprivation.
The findings reported in today'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.
Also, after too little sleep, the fat cells' ability to use insulin properly, dropped by 30%. When fat cells don't respond to insulin properly, lipids (fats) circulate in the blood, which can lead to health problems, 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.
Low leptin levels tell your body it's starving and increase your appetite, says Eve Van Cauter, another author on the study and co-director of the Sleep, Metabolism and Health Center at the University of Chicago.
David Neubauer, associate director of the Johns Hopkins Sleep Disorders Center, says, "This study reinforces the importance of good sleep generally in promoting health."
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