Acute fatigue: How you physically and mentally feel at the end of a long day.
Chronic fatigue: Long-term fatigue which has serious physiological and psychological effects.
Performance degradation due to acute fatigue can be correlated to blood alcohol level.
The longer a person is awake, the sleep urge and need becomes stronger. The pressure to sleep grows more intense as the day progresses, then dissipates when one sleeps at night.
As one extends wakefulness into routine sleep hours, the urge to sleep increases. The primary factor that affects alertness is the number of hours continuously awake. At about the 16 hour mark, sleepiness begins to affect performance of the average individual.
Studies show that after 18 hours of wakefulness, participants showed a 30% decrement in performance and problem-solving ability.
Chronic fatigue can be caused by multiple back-to-back long days with less than the required sleep each night. This leads to serious performance degradations. Performance degradations include the following: