Sleeping disorders such as sleep apnea and insomnia are common factors in causing sleep deprivation.

 Lack of sleep can cause high blood pressure as well as a rise in cholesterol.  Sleep apnea patients are the most at danger when it comes to heart disease.

 The inability to metabolize glucose brought on by sleep deprivation can lead to Type 2 Diabetes.

 In areas of the brain lack of sleep can lead to the decline of memory and certain learning skills. In some parts of the brain, such as the prefrontal lobe, there is more activity due to overcompensation.

  Hypothalamic neurons produce neurotransmitters called GABA, which stop neurons from firing which have serotonin, histamine, norepinephrine, glutamate and hypocretin in them. This action promotes sleep. So if REM is never achieved as it is with sleep apnea patients this never occurs.