In a similar study in 2008, scientists at the Karolinska Institute in Stockholm found that when subjects slept four hours a night over five days, and then “recovered” with eight hours a night over the following week, they still showed slight residual cognitive impairments a week later, even though they reported no sleepiness. But in another study, also at the Walter Reed Army Institute of Research, scientists found that people recovered much more quickly from a week of poor sleep when it was preceded by a “banking” week that included nights with 10 hours of shuteye. In other words, if you know you have a week of little sleep ahead of you, try loading up on sleep beforehand, not simply afterward.
