The science is indisputable. All three types of fatigue, whether physical (body), mental (mind), or neurocognitive (brain), impair human performance. The most insidious and dangerous form in workplaces is neurocognitive fatigue, which is caused by insufficient Delta-wave or deep, restorative sleep that the human brain requires every 24 hours. The particular parts of the brain that suffer from this type of fatigue are the four lobes of the cerebral cortex—the parts of our brain that control cognitive processes such as pattern recognition, auditory discrimination, visual processing, memory, speech, reasoning, planning ahead, problem solving, and decision making.