When your boss asks you to pull an all-nighter, you probably stock up on chips, pizza, and soda to help get you through. Two new studies, presented at a meeting of sleep researchers in Boston, try to shed light on what happens in the brain when you put up with lack of sleep for too long.
In the first study, researchers from St. Luke's Roosevelt Hospital Center and Columbia University in New York looked at the brain activity of 25 normal-weight volunteers after five nights of sleep deprivation—four hours of sleep—and five nights of normal sleep.
After sleep deprivation, the pleasure-seeking centers of the brain were activated more when participants looked at pictures of unhealthy food like “pepperoni pizza, cheeseburgers and cake,” lead researcher Marie-Pierre St-Onge, Ph.D. told CNN.
After several days of sleeping well, though, both healthy and unhealthy food images activated those areas about the same amount.
In the second study, by researchers from the University of California, Berkeley, 23 healthy adults rated their craving for 80 foods during a functional MRI scan. This was repeated twice—after one night of normal sleep and after 24 hours of sleep deprivation.
In this case, lack of sleep dampened brain activity in areas involved in using information and making decisions. The reward centers were not activated more by sleep deprivation, as in the first study, but the ability to make good food choices was affected.
The different results between the two studies may have something to do with the small number of people examined, or the difference between the effects of poor sleep and staying awake for 24 hours.
More research is needed, but sleep deprivation has already been linked to overeating and poor food choices. Something to keep an eye out for during your next all-nighter.