Interestingly, a number of studies have shown that sleep loss increases irritability and depresses mood. The possible contribution of sleep loss to violent behavior has never been considered, let alone investigated. Relationship to health The importance of good sleep for good mental and physical health may seem obvious but is still a matter of controversy in the field. Well-controlled studies have shown that total sleep deprivation kills a rat in approximately two weeks. Less drastic studies in humans have indicated that sleep deprivation impairs immune function.
Sleep apnea is associated with a variety of neuroendocrine disorders.
This delay in the onset of the quiescent period of cortisol secretion, which normally occurs during the evening and early part of the night, suggests that the mechanism of HPA recovery from stimulation is affected by sleep loss. Thus, sleep loss may alter the rate of recovery of the HPA response to endogenous stimulation by circadian factors. These findings raise the possibility that the resiliency of the HPA axis to exogenous stimulation by stressors may also be affected by sleep loss. In particular, sleep disturbances are one of the major health complaints of older adults and consist primarily of increased amounts of wakefulness and reduced amounts of deep sleep as well as REM sleep. It is also likely that the mechanisms of recovery from sleep loss are impaired in aging, resulting in an ever decreasing ability to reverse the adverse impact of sleep loss on HPA function.