The effects of total sleep deprivation in healthy humans.
The sleep quality declines with various chronic pain conditions as shown in, e.g., fibromyalgia (common and chronic syndrome that causes bodily pain and mental distress), burn injuries, and back pain. Sleep impairments have been described as valuable predictors for new incidences and worsening symptoms linked to chronic pain. Patients with co-occurring sleep disorders seem to experience worsened pain symptoms. Brain areas such as the periaqueductal gray are known to modulate both sleep stages and nociception (the detection of painful stimuli). The raphe nuclei are involved in the descending pain control system and the ascending reticular activating system (ARAS). These areas may account for the link between sleep loss and decreased pain inhibition.