Sleep deprivation can cause lasting effects to your mental performance up to a week later. In a study published last week in the journal PLoS One, Polish researchers examined participants between the ages of 20 and 22. Each one slept normally for four days to get a baseline amount of sleep needed each night. Then the researchers cut their sleep by 30 percent for the next 10 nights. Finally, the subjects got to sleep normally again for seven days. Not surprisingly, response times and accuracy dropped during the period of sleep deprivation. But, performance in those areas still hadn’t returned to normal even after seven days of sleep recovery. If you work in a job where performance is important, and most of us do, realize the long-term risk of sleep deprivation, and do what you can to avoid it.