Theory of sleep

In the field of sleep research, there is a wide range of theories: from particular ones concerning specific aspects of sleep, such as the connection of REM sleep with dreams, to more general ones, the authors of which try to explain the need for sleep. This article focuses on the latter type of theory, which can be divided into five general categories:

1. The theory of recovery. Sleep is a necessary period of recovery from unhealthy conditions or States of exhaustion that develop during the waking period. This is the oldest (proposed by Aristotle) and most common theory of sleep. Living organisms go to sleep when they are tired and Wake up refreshed.
2. The defense's theory. Sleep helps to avoid continuous and excessive stimulation. Pavlov, for example, considered sleep as a cortical inhibition that helps protect the body from overexposure. Living organisms sleep not because they are tired or exhausted, but to protect themselves from exhaustion.
3. Theory of energy saving. This theory emerged from animal studies that found a strong Association between high levels of metabolic activity and total sleep time. Since sleep, like hibernation, reduces energy expenditure, animals with high levels of metabolic activity reduce their energy requirements by sleeping longer.
4. Theories of instinct. In these theories, sleep is considered as a species-specific, morpho-physiologically realized instinct, triggered by environmental signals, which necessarily cause the appropriate sleep response in a specific situation.
5. The theory of adaptation. This category includes the most current sleep theories that treat sleep as an adaptive behavioral response. Proponents of this approach consider sleep to be a regular time-out reaction due to the pressure of predators and the need to get food. Thus, sleep does not appear to be a dangerous behavior (as in recovery theories), but a survival-enhancing reaction.

See "Sleep theories. Continuation​​​​​​​»