Understanding the Sleep-Chronic Pain Connection
Pain, whether acute or chronic, disrupts sleep. Chronic pain specifically is a true sleep disruptor. In the presence of chronic pain, there are extended periods of poor quality sleep or insomnia and either of those situations results in extended health consequences. Sleep deprivation will heighten the perception of pain, and chronic pain will continue to disrupt sleep. These two conditions literally feed off each other.
What are some unique features of the sleep patterns of individuals who suffer with chronic pain?
A typical night of sleep includes periods of deeper sleep, superficial sleep and even some brief periods of awakening, known as “micro-arousals.” Individuals who do not suffer with chronic pain deal well with these micro-arousals, and are mostly unaware of them. People who suffer persistent chronic pain, however, experience more intense micro-arousals, because they feel pain again as they reawaken, and this causes an increase in sleep disruption(s), so much so that chronic pain sufferers can feel as though they didn’t sleep at all. We call this paradoxical insomnia.
What is paradoxical insomnia?
This condition, also called “sleep state misperception,” happens when people believe they are awake for most of the night, but when they undergo EEG testing, the brain wave measurements show that they actually slept. Even when such people get several hours of sleep, they don’t feel it lasted long enough to enable them to experience the restful properties of sleep. This increases anxiety, which in turn can increase pain perception, further interfering with the ability to sleep. It’s really a vicious cycle.
With paradoxical insomnia, you may not feel sleepy but you will likely feel generalized fatigue which will interfere with the ability to conduct activities that require concentration.
How are the different sleep stages affected by chronic pain?
The main reason why a person with chronic pain may feel awake when they are actually sleeping is because they spend more time in the more superficial stages of sleep. Deep sleep (slow wave sleep or SWS) is necessary in order for a person to feel rested after a full night of sleep. SWS also is associated with consolidation of new memories, especially non-emotional fact-based memories. If a person is awakened during a SWS phase, they will typically feel quite groggy, compared to being awakened during other sleep phases. That heavy grogginess is referred to as sleep inertia. It’s the reduction of SWS phase time that accounts for the lack of feeling that the person had restful sleep, no matter how many hours the person was actually in bed “sleeping.”
Fibromyalgia** and the “pain and sleep“model**
There’s been a lot of research on fibromyalgia because it is considered a condition of unexplained chronic pain (though more is now known about its etiology). It is believed that there is an increased firing of the sensory neurons in the posterior spine that increases the perception of pain. Special features have been identified in the sleep patterns of individuals with fibromyalgia such as alpha waves, which appear during the “drowsy but awake” state of sleep. Unique to fibromyalgia is that they happen inside the slow waves during sleep. This is known as “alpha intrusion into delta.” What this means is that there is a wakeful; period within what is supposed to be a deep sleep period. This is one of the ways that a vicious cycle of pain and insomnia perpetuate each other.
How does a person break this pain-insomnia cycle?
There is more involved than simply taking pain medication and sleeping pills. It’s important to identify the pain triggers, to break the misperception of lack of sleep when sleep has actually occurred, and to adopt the habits of good sleep hygiene:
Make sleep a planned event: Schedule the time and do not try to do other things during “get ready for sleep” time.
Try to go to sleep and awaken at the same time every day (even on weekends).
Make an effort to reduce tension — both physical and mental — before trying to fall asleep. The choice of relaxation techniques is very important. Progressive muscle relaxation is the most commonly used technique for insomnia, but it may not be appropriate for people suffering heightened muscular pain. Place more emphasis on reducing mental stress.
In cases of chronic pain, sleep position is more important than in other types of insomnia. Special pillows are available for certain pain areas such as the shoulders and arms, if this is your preferred position of sleep. If you like to sleep on your back, place a pillow under your knees to maintain the normal curvature of the spine.
There are specific medications for neurogenic-induced pain, such as Lyrica and Neurontin. Dosages for these medications need to be carefully adjusted under the guidance of a physician. GHB is currently being used for patients with fibromyalgia pain.
If you are struggling with chronic pain-disrupted sleep, then adhering to these sleep hygiene tips, managing stress, and identifying and treating pain triggers can help provide the restful sleep we all critically need.
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Eli Hendel, M.D. is a board-certified Internist and pulmonary specialist with board certification in Sleep Medicine. He is an Assistant Clinical Professor of Medicine at Keck-University of Southern California School of Medicine, and Qualified Medical Examiner for the State of California Department of Industrial Relations. His areas of expertise in private practice include asthma, COPD, sleep disorders, obstructive sleep apnea, and occupational lung diseases.