The physiological and psychological importance of sleep deprivation

¶ … Sleep Behavior and Habits

Scientists have known for decades that the human sleep and wakefulness are controlled by complex factors that influence the circadian rhythm that regulate sleep in all mammalians and in most other forms of so-called higher biological life. More recently, physiologists have identified very important direct connections between sleep cycles, and sleep deprivation in particular, and human health. Specifically, sleep deprivation and the disruption of regular sleep-wake cycles have been implicated as factors that contribute to loss of mental focus, intellectual productivity, human error, emotional stability, resistance to bacterial infection, depression, and even healthful weight maintenance. In addition to the importance of sufficient sleep and the regularity of sleep cycles, there is even empirical evidence indicating that the quality of sleep is significantly affected by very small amounts of ambient light during sleep.

The Physiological and Psychological Importance of Sleep

Human studies on sleep and on sleep deprivation have demonstrated that human beings cannot function without sufficient sleep (Siegel, 2005). After only one night of inadequate sleep, mental acuity, memory, operational efficiency, and mood deteriorate substantially. For this reason, regulatory agencies impose strict requirements and limitations on the amount of time in between the shifts scheduled for truck drivers and (especially) civilian pilots (Siegel, 2005). Similarly, military training (particularly in connection with special forces) emphasizes preparation for performance under the pressure of sleep deprivation. Prisoner of war survivor training also emphasizes resistance to forced sleep deprivation, precisely because it is a commonly used form of purposeful stress inducement used for interrogation purposes and also simply for torture (Pauley, 2004; Siegel, 2005). Short-term sleep deprivation interferes with concentration and mood, but prolonged sleep deprivation induces psychosis and eventually death (Siegel, 2005). In principle, the primary physiological importance of sleep relates to the role of the pituitary in stimulating the production of Human Growth Hormone (HGH) which is highly dependent on darkness (Lamond, Dorrian, Roach, et al., 2003; Pauley, 2004).

Sleep and Human Health

There are numerous consequences of sleep deprivation in connection with even minor sleep disruptions, prolonged loss of small amounts of sleep, and to frequent disruptions to sleep such as those caused by snoring (Lamond, Dorrian, Roach, et al., 2003; Pauley, 2004). Empirical research documents that the detrimental effects of minor sleep deprivation of driving are comparable to the effects of driving while under alcohol intoxication and suggest that sleep deprived drivers account for more property damage and insurance claims than all instances of driving while intoxicated by alcohol and illicit drug use in the United States (Lamond, Dorrian, Roach, et al., 2003).

The importance of regular sleep has also been demonstrated empirically by studies of American shift workers, such as those who typically rotate regularly from day shifts to night shifts (Lamond, Dorrian, Roach, et al., 2003). In that regard, workers who regularly change schedules from day to night shifts and vice-versa account for more absenteeism, poorer performance, higher rates of accidents and injuries, and in the most general sense, lower performance and worse physical health than workers whose shifts remain constant. Most significantly, it is the shift from one schedule to the other that is more important than whether workers maintain night shifts or day shifts regularly. The available research suggests that it is the disruption of the circadian rhythm and the fact that it requires several weeks to reset properly that is responsible (Lamond, Dorrian, Roach, et al., 2003; Pauley, 2004). Equally significant is the degree to which lighting issues affect the quality and restorative value of sleep among workers who must sleep during daylight hours (Pauley, 2004).

Conclusion

Sleep has long been recognized as being important to human health and welfare, even long before any modern scientific appreciation of the specific mechanisms through which it affects human psychology and physiology. Short-term sleep deprivation detrimentally affects performance in virtually every conceivable respect; long-term sleep deprivation can trigger profound psychological dysfunction and even death. The fundamental importance of sleep is also demonstrated by the degree to which comparatively minor types of sleep disruption and deprivation affect human performance and health. For this reason, contemporary physiologists, and occupational and industrial psychologists have begun incorporating sleep research into recommended protocols, particularly in connection with work shifts and work-shift rotation among shift workers.