Getting too little sleep can do more than leave you feeling groggy in the morning. New research has found sleep deprivation not only boosts hunger but also saps energy levels during the day – two factors that can significantly boost the odds of packing on the pounds.
The study, conducted by German and Swedish researchers, suggests getting a good night's sleep is as important to maintaining healthy weight levels as eating well and exercising.
The findings, which were presented at an annual meeting of the Society for the Study of Ingestive Behavior, indicated sleep loss has ramifications not only for how many calories we consume but also for how much energy we burn off.
To reach their conclusions, researchers from the German Universities Tubingen and Lubeck and Uppsala University in Sweden tracked a group of sleep-deprived individuals – assessing their hunger levels, physical activity and the calories they burned during the day.
Physical activity was measured by devices worn on the wrist that detect acceleration. Energy used by the body was assessed by indirect calorimetry, a method which estimates how much heat is produced as a person uses oxygen.
They found sleep deprivation raised the amount of the "hunger hormone" ghrelin in participant’s blood, which made them hungrier. In fact, the less sleep a person had the hungrier they were.
After even one night of disrupted sleep, study participants were less active and their bodies used less energy when they were resting.
“This research tells us when we are sleep deprived we are likely to eat more calories because we are hungrier,” the researchers concluded. “This alone might cause us to gain weight over time. However sleep loss also means we burn off fewer calories which adds to the risk of gaining weight.”