Sleep, cognitive performance, and mood

The evidence that sleep deprivation adversely affects cognition and motor performance is striking. One study showed that people who were awake for up to 19 hours scored substantially worse on performance and alertness than those who were legally intoxicated.

Other studies have found:

• After one night of total sleep deprivation, subjects scored significantly lower on tests of judgment, simple reaction time, explicit recall, and inverse word reading.

• Daytime alertness and memory are impaired by the loss of sleep, especially when sleep loss is sustained over a few nights. Getting three or five hours of sleep a night for seven consecutive nights can significantly impair alertness and motor performance. It is well documented that sleep loss can adversely affect mood. We all know how irritable we become after a night spent tossing and turning. A growing body of medical evidence links inadequate sleep with anger, anxiety, and sadness.