The Body During Sleep

Abstract

If we are going to understand sleep completely, we also need to understand what effects sleep has on the body and vice versa. Prior to the latter half of the twentieth century, it was assumed that the physiology of the body was the same when asleep as it was when awake. Since it is generally easier to study the body during waking, little attempt was made to investigate its physiology during sleep. More recent studies have awakened us to the realization that in many ways we are physiologically different during sleep. Some of these changes are large, involving whole organ systems, but others are more subtle. Yet, all of the differences are important. Additionally, contrary to common belief, we do not sleep simply because our body wears out while awake and needs sleep to reverse this effect. It is now realized that changes in any of several physiological processes may either facilitate or impede sleep. Also, what we do and what is done to us while awake that affects our physiology can also have an effect on our subsequent sleep.

Specific references to statements in this chapter that can be found in multiple, widely available sources are not included in the text. A selection of these sources is listed below and can also be consulted for verification or more detail. (Amlaner and Fuller 2009; Chokroverty 2009; Horne 2006; Kryger et al. 2011; Lee-Chiong 2011).