Lack of sleep or poor sleep
The average person needs 8 hours sleep every 24-hour cycle. Sleep prior to work is the most prominent factor that influences the waking state, the level of alertness of the driver . A chronic lack of sleep is the result of not having enough sleep during a long period. An acute lack of sleep can occur after just one bad or short night. If there has been too little sleep during a 24-hour period, we refer to it as a partial, acute lack of sleep. There is a complete, acute lack of sleep if, within a period of 24 hours, there has been no sleep at all.
Besides quantity of sleep, the quality of the sleep is also of great importance. If sleep is regularly interrupted, this leads, just as too little sleep does, to day-time fatigue. The quality of sleep is influenced by, among other things, sleeping disorders e.g. sleep apnoea (a temporary breathing stoppage while sleeping) and narcolepsy (the tendency to suddenly fall asleep). But it can also be a side effect of chronic diseases and/or medication or the result of external factors, such as a noisy or unpleasant sleeping environment.