Sleeping for four hours a night for 5 days in a row can affect the brain just like acute total sleep deprivation, says a new study.
"Instead of going to bed when they are tired, like they should, people watch TV and want to have an active social life," said Dr. Chiara Cirelli from University of Wisconsin-Madison.
"People count on catching up on their sleep on the weekends, but it may not be enough," she added.
Sleep restriction can also increase resistance to insulin, leading to a risk of diabetes," she said.
In the study, the more effective the researchers were in keeping the rats awake during those 20 hours, the larger the sleep rebound they saw during the following four hours.
SWA (slow wave activity) is the best marker of an individual's need to sleep as well as the intensity of sleep that follows a period of wakefulness.
Even when the animals seemed awake and were moving around, heightened SWA was evident in their "wake" EEG.
"High SWA levels during periods of both sleeping and waking signal that you need to go to sleep," said Cirelli.
The study appears in the current online edition of the Proceedings of the National Academy of Sciences.