Research indicates that the normal waking day is between 14 and 16 hours and that lapses in vigilance increase and become longer if the normal waking day is extended. It also shows that the ability to consider options decreases as people who are fatigued become fixated on a course of action.

Automatic processes (such as radio calls and routine behavior) are affected less by fatigue than controlled processes (such as more complex behavior, responses to new situations and decision making).

  • An Australian study correlated sleep deprivation with blood alcohol content (BAC) in terms of how likely they were to result in a collision. Staying awake for 18 hours corresponds to a BAC of .05; maintaining wakefulness for a full 24 hours equates to a BAC of .10, which is over the legal limit of .08.

  • A study published in the Archives of Internal Medicine that surveyed hospitalized participants in automobile accidents found that drunk driving and driving while fatigued were equally risky. Both doubled the chance of being in an accident.

  • A study looking at the impact of a night of sleep deprivation on novice developers’ performance recruited 45 undergraduates and asked them to tackle a programming task. In their experiment, half stayed awake the night before while 22 slept usually. They found that a single night of sleep deprivation lead to a reduction of 50% in the quality of the implementations.