They were tested once after a normal night of seven to eight hours of sleep. Then they were tested after a night of partial sleep loss; they went to bed four hours later than normal but woke up at the usual time.
Results show that partial sleep deprivation caused both mood and performance to be worse. Increasing time awake during the day also had a slightly negative effect on performance; this was associated with decreased alertness and increased fatigue.
Are you sleep deprived? Here are seven signs you need sleep from the AASM.
Image by Marius Boeriu