Generally speaking, the longer an organism is awake, the more it feels a need to sleep. The balance between sleeping and waking is called Sleep Homeostasis. Induced or perceived lack of sleep is commonly called Sleep Deprivation. Sleep deprivation tends to cause slower brain waves in the frontal cortex, shortened attention span, higher anxiety, impaired memory, and a grouchy mood. Conversely, a well-rested organism tends to have improved memory and mood. In rats, sleep deprivation causes weight loss and reduced body temperature.
If prevented from sleeping for several weeks, rats die!!. So Insomnia can be fatal, at least in rats. In humans, sleep deprivation has been studied up to 11 days, during which subjects are more likely to gain weight. Human deaths from sleep deprivation alone are not known. The need for sleep must be balanced against the circadian element for satisfactory…
