Chronic Pain and Poor Sleep: A Vicious Cycle

By Gerard J. Meskill, MD

 

Chronic pain is extremely common in America, and it can affect sleep quality. According to the 2015 Sleep in America Poll (1),
21 percent of Americans experience chronic pain, while another 36 percent have experienced acute pain in the past week.

Most people with chronic pain find their symptoms worse while lying in bed trying to sleep, when the external stimuli of the world are no longer providing distraction from their ailments.

Poor sleep can make pain syndromes worse, and worsening of the pain syndrome can feed into perpetuation of poor sleep quality.

Sleep deprivation is an enormous problem in this country as it is. One in three individuals without pain report in the past week that they don’t always or often get a good night’s sleep, the sleep they need to feel their best, or have had trouble falling or staying asleep. In the sub-population of those suffering with pain, it is even worse. According to the National Sleep Foundation (2), people with chronic pain average 42 minutes of sleep debt nightly. Furthermore, only 45 percent of those with acute pain and 37 percent of those with chronic pain report good or very good sleep quality. More than half of those individuals with sleep difficulties and pain report that their poor sleep interfered with their work. This can jeopardize employment and further deteriorate quality of life.

Mature Man having trouble Sleeping

CHRONIC PAIN IMPAIRS SLEEP QUALITY

There are many reasons why chronic pain can impair sleep quality. The obvious one is that dealing with pain while trying to fall asleep makes sleep initiation more difficult. Once sleep finally is achieved, any arousal out of sleep allow for perception of the pain phenomenon again, thus prolonging the time it takes to fall back asleep. Since sleeping lowers our overall sleep drive, it is more difficult to fall back asleep with each awakening. As this pattern continues, the way the brain perceives the bed and sleep changes. Much like the Russian psychologist Pavlov taught his dog to associate the sound of a bell with food, the brain starts to anticipate difficulty sleeping every time an individual suffering from insomnia gets into bed. This leads to increased adrenaline levels (“The Fight or Flight” response), which makes it even harder to fall asleep.

POOR SLEEP WORSENS CHRONIC PAIN

To make matters worse, poor sleep quality and shorter total sleep time can make the pain syndrome worse. There are many reasons for this. First, one of the reasons we sleep at night is to allow the body the opportunity to make necessary repairs.

Proper sleep leads to quicker healing time and faster recovery from injuries and
illnesses. Conversely, poor sleep can
prolong recovery time.

Individuals with more disrupted sleep have increased production and release of inflammatory markers in the bloodstream (3). This can lead to more inflammation and pain. Additionally, the brain’s threshold for perceiving stimuli changes, depending on the amount and quality of sleep. Neurologists have long known that sleep deprivation can lead to a lower seizure threshold, thus increasing the likelihood of an individual having a seizure. The same is true of the pain threshold. Peripheral nerves carry signals to the brain all the time. It is the brain’s job to determine which signals are worthy of a response and which are background noise. The same signal intensity traveling from a peripheral nerve may be interpreted as sufficient to warrant a pain response by the sleep-deprived brain, while it may be considered inconsequential by the rested brain.

Chronic Pain & Sleep Cycle

SLEEP DISORDERS CAN WORSEN SLEEP AND MAKE CHRONIC PAIN WORSE

Sleep disorders are common in the general population, and they are even more common in individuals with chronic pain. Nearly one in four people with chronic pain (23 percent) report being diagnosed with a sleep disorder by a doctor, compared with just 6 percent of the rest of the population (2). There are several common sleep disorders that when combined with a chronic pain syndrome can have a negative impact on sleep quality.

As discussed above, chronic insomnia is the persistent inability either to fall asleep or stay asleep. Treatment of insomnia is multi-faceted, incorporating behavioral modification, relaxation training, and sometimes prescription medications. Simple behavior changes can help break the subconscious “Pavlov’s Dog” association between the bed and not being able to sleep. These include keeping a regular bedtime and wake time seven days per week; spending no more than 8 hours per night in bed (even if you don’t sleep the whole time); getting 30 minutes of sunlight exposure in the morning within 15 minutes of waking up; avoiding daytime napping; avoiding bright light, electronics, and stimulating activities within one hour of bedtime; and avoiding all other activities besides sleep and sexual intercourse while in bed.

Simple behavior changes can help break the subconscious “Pavlov’s Dog” association
between the bed and not being able to sleep.

Boreal Owl at night

Another common condition similar to chronic insomnia is Delayed Sleep Phase Syndrome (DSPS). This condition is often confused with insomnia because in both conditions, the sufferer has chronic difficulty falling asleep. However, those with DSPS have an internal clock that wants to go to bed and wake at later hours than what their societal obligation will allow … in other words they’re “night owls.” Left to their preferred hours (e.g., go to bed at 3 a.m. and wake at 11 a.m.), these individuals fall asleep easily and can sleep through the night. Management of this condition involves some of the same treatments as those listed above for chronic insomnia. However, the focus is on adjusting the internal circadian clock by using bright light exposure in the morning and timed use of melatonin at night.

Restless Legs Syndrome (RLS) is a clinical condition in which a limb or limbs (usually the legs) have an uncomfortable, cramping, or ill-defined sensation that briefly remits with movement but then returns again.

RLS typically occurs more at night and when an individual is lying down or sitting and gets better with movement, especially walking. RLS can contribute to difficulty initiating and maintaining sleep. Medical research has demonstrated that individuals with fibromyalgia and rheumatoid arthritis are much more likely to have RLS than the general population (4). Some with RLS suffer from iron deficiency, and those individuals can see improvement in their symptoms with oral iron supplementation. Many others with RLS do not have iron deficiency, and therefore, iron pills do not help. In these cases, many times a low-dose prescription medication can help alleviate RLS symptoms and improve sleep.

Obstructive Sleep Apnea (OSA) is a condition where the relaxation of upper airway muscles leads to frequent disruptions in airflow and sleep fragmentation. While the bulk of the medical community’s focus on OSA centers around pauses in breathing and drops in oxygen during the night, the American Academy of Sleep Medicine amended the diagnostic criteria to include more subtle events that lead to sleep disruption (such as in “the Upper Airway Resistance Syndrome” or “UARS”) without being so severe as to close the airway or drop oxygen.

This distinction is critical because many patients with chronic pain syndromes, particularly chronic tension-type headache (TTH), fibromyalgia, and chronic fatigue syndrome suffer from OSA or UARS. Research has shown a decrease in slow wave sleep (“deep sleep”) and rapid eye movement (REM) sleep in people suffering from fibromyalgia, which is thought to be a contributing factor to the chronic fatigue associated with this condition (5). As stated above, impaired sleep leads to increased inflammatory markers in the blood and lower pain thresholds, two phenomena observed in fibromyalgia. In those with TTH, particularly those who report waking with headaches, temporomandibular joint (TMJ) pain, or jaw pain, UARS and OSA should be suspected. Research has shown that teeth clenching during the night is a protective mechanism to try to keep the airway open by keeping the jaw and tongue from sliding toward the back of the throat (6). This behavior can alleviate significant airway blockage, but it also creates tremendous muscle strain during the night, which can cause TTH and TMJ pain.

Effective treatment of chronic pain often
requires a team approach, and a sleep
clinician can be an invaluable
member of that team.

Diagnosis of OSA requires an overnight polysomnogram (“sleep study”) to detect episodes of disturbed breathing. This test can be performed either at home or in a sleep laboratory, depending on what other factors are being considered. UARS also requires an overnight sleep study, but because home sleep tests do not detect the subtle breathing abnormalities associated with this condition, testing must be done in a sleep laboratory. Both conditions have the same treatment options, which include Continuous Positive Airway Pressure (CPAP) therapy, oral appliance therapy, and corrective surgery (tonsillectomy, nasal septoplasty, facial reconstruction surgery, and others). In children, orthodontic procedures (e.g., rapid maxillary expansion) can widen the airway and in some cases prevent the condition from becoming chronic.

Effective treatment of chronic pain often requires a team approach, and a sleep clinician can be an invaluable member of that team. Chronic pain worsens sleep, and poor sleep worsens pain. It’s a vicious cycle that can only be broken when all of the contributing factors are taken into account.

REFERENCES

  1. 2015 Sleep in America™
  2. National Sleep Foundation website.
  3. Mullington JM, Simpson N, Ph.D., 1 Meier-Ewert HK, Haack M. Sleep Loss and Inflammation. Best Pract Res Clin Endocrinol Metab. 2010 Oct; 24(5): 775–784.
  4. Yunus M, Aldag JC. Restless legs syndrome and leg cramps in fibromyalgia syndrome: a controlled study. BMJ 1996; 312.
  5. Branco J, Atalaia A, Paiva T. Sleep cycles and alpha-delta sleep in fibromyalgia syndrome. The Journal of Rheumatology 1994, 21(6):1113-1117.
  6. Oksenberg, A., Arons E. “Sleep bruxism related to obstructive sleep apnea: the effect of continuous positive airway pressure.” Sleep Med. 2002 Nov; 3(6):513-5.

 

About the Author:

Dr.MeskillGerard J. Meskill, MD, is a neurologist and sleep disorders specialist. He completed his sleep fellowship training at the Stanford Center for Sleep Sciences and Medicine. This Center is the birthplace of sleep medicine and includes research, clinical, and educational programs that have advanced the field and improved patient care for decades. He now practices sleep disorders medicine and neurology in the Greater Houston area at Comprehensive Sleep Medicine Associates, with offices in the Woodlands, the Houston Medical Center, and Sugar Land, Texas. Dr. Meskill and his colleagues make routine contributions to http://houstonsleep.net/sleepblog/ to help raise awareness of sleep-related medical conditions.