In Sleep Debt and the Mortgaged Mind, William Dement discusses how to recognize the signs of dangerous sleepiness and urges the importance of education on sleep debt.
Generally people need to sleep one hour for every two hours awake, and we need eight hours. The brain keeps an exact account of how much sleep it is owed. The brain tries to hit this mark, and the further you get from this number of hours the harder the brain tries to force you to go to sleep.
We use the term “sleep debt” because an accumulated loss of sleep is like a monetary debt, and must be paid back. Sleep debt may accumulate in small increments over many days. As debt grows your energy, mood and cognition will be undermined.
Misunderstanding the rules of sleep debt can be dangerous. A few hours of extra sleep does not alleviate sleep debt. If you feel sleepy or drowsy in the daytime, then you have a sizable sleep debt. Sleep debt is the physical side and feelings of sleepiness and drowsiness are the psychological side. We may not feel sleepy if we are doing something that excites us. We have a strong tendency to fall asleep when we reduce the stimuli that are keeping us awake.
When a crash is contributed to alcohol, the real culprit , or coconspirator is often sleep deprivation. Alcohol may not be a potent sedative by itself, but when paired with sleep debt can be very dangerous, which is called “fatal fatigue”. Some people can be fine after one drink one day (when having little sleep debt), yet can be a hazard if they have the same drink on a day that they have a large sleep debt.
Sleep debt is a silent and deadly epidemic. People are unaware that when your eyelids are trying to close that this is the last step before you fall asleep. It starts as a sensation of drowsiness, you start having the conversations to yourself to stay awake. Then you start using efforts to fight off sleep(e.g. opening a window, turning on the radio). And before you know it...