Sleep deprivation could be doing more damage than just making you feel groggy. New research has shown that lack of sleep promotes insulin resistance, a condition that disrupts normal metabolism and eventually leads to diabetes. If you’re trying to lose weight, the study suggests that getting a good night’s sleep is just as important as a healthy diet and plenty of exercise.
Sleep deprivation and weight gain
It’s obvious that sleep deprivation makes you tired, cranky and slow-witted. Sleep researchers know that lack of sleep can lead to overeating because it stimulates the hunger hormone ghrelin and suppresses the fullness hormone leptin. Previous studies have also found that sleep deprivation can affect insulin sensitivity. But scientists at the University of Chicago say their study is the first to show how lack of sleep affects activity at the cellular level that could lead to weight gain.
Sleep deprivation and metabolic aging
The new study, published in the Annals of Internal Medicine, found that sleep deprivation impairs the ability of fat cells to respond to insulin, a hormone that regulates metabolism by allowing cells to convert sugar into energy. According to lead author Matthew Brady, over time the disruption could lead to weight gain, type 2 diabetes and other health problems.
In the study, seven men and women healthy enough to endure an intense period of sleep deprivation spent eight days and nights in a sleep lab. They slept normally on four nights and allowed just 4.5 hours of sleep on the other nights. According to Brady, this schedule simulated 10 to 20 years of metabolic aging.
Rapid onset insulin sensitivity
To remove the influence of sleep deprivation on the hunger hormone ghrelin and the fullness hormone leptin from the study, researchers put the participants on a strict diet. After four nights of sleep deprivation, their insulin sensitivity dropped 16 percent on average. What’s more, insulin sensitivity in their fat cells dropped by 30 percent—a level seen in obese people and diabetics.
How the damage is done
Drilling down, the researchers found that after sleep deprivation, fat cells needed three times as much insulin to activate an enzyme that plays a key role in regulating blood sugar called Akt. Healthy fat cells store fat to be used for energy as needed. They also keep fatty acids and lipids from the bloodstream, where they can damage tissue.
Over time, fat cells with the insulin-resistant Akt enzyme allow excess sugar and lipids to leach into the blood, where they eventually accumulate in the liver and other tissues.
How much sleep do you need?
The findings suggest that sleep is important for healthy cells throughout the body. So how much sleep do you need?
Conventional wisdom says adults need seven to nine hours a night. But exactly how much sleep is healthy depends on the individual.
To figure out your own sleep needs, study co-author Eve Van Cauter recommends not setting the alarm during your next vacation. After a few days of sleeping in, your sleep debt is repaid and your natural sleep time will stabilize. The length of that period is how much sleep you need.
Sleep guidelines according to the National Sleep Foundation
Newborns (0-2 months): 12-18 hours
Infants (3-11 months): 14-15 hours
Toddlers (1-3 years): 12-14 hours
Pre-schoolers (3-5 years): 11-13 hours
School-age kids (5-10 years): 10-11 hours
Adolescents (10-17 years): 8.5-9.25 hours
Adults: 7-9 hours