Sleep Debt

Sleep debt or sleep deficit is the cumulative effect of not getting enough sleep. A large sleep debt may lead to mental and/or physical fatigue.

There are presumed to be two kinds of sleep debt, caused by partial sleep deprivation or total sleep deprivation. Partial sleep deprivation occurs when a person or a lab animal sleeps too little for many days or weeks. Total sleep deprivation means being kept awake for days or weeks. There is debate in the scientific community over the specifics of sleep debt, and it is not considered to be a disorder.

sleep deprivation is characterized by having too little sleep it can be either chronic or acute. Long-term sleep deprivation causes death in lab animals. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain.

Complete absence of sleep over long periods is impossible for humans to achieve (unless they suffer from insomnia) brief microsleeps cannot be avoided.