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Insomnia Until it Hurts

The role of sleep deprivation in muscle pain and other kinds of chronic pain

2,750 words, published 2008, updated 2012
by Paul Ingraham, Vancouver, Canada bio
I am a science writer, the Assistant Editor of ScienceBasedMedicine.org, and a former Registered Massage Therapist with a decade of experience treating tough pain cases. I’ve written hundreds of articles and several books, and I’m known for sassy, skeptical, referenced analysis and a huge bibliography. I am a runner and ultimate player, and live in beautiful downtown Vancouver, Canada. • full bioabout SaveYourself.ca

We are used to thinking of insomnia as a symptom of stress — and it is.12 However, it is also hazardous itself. Based on clinical observations and unpleasant personal experience, I have long believed that the pain and stiffness of myofascial trigger points — muscle knots — is probably aggravated by insomnia or even mild but chronic sleep deprivation. There is no direct scientific evidence to support this (to the best of my knowledge), but there is plenty of indirect evidence. In this article I’ll discuss what little is known, and what we might reasonably guess, about the relationship between sleep disturbance and muscle pain.

The biological importance of sleep

Certainly serious insomnia is nothing to mess around with. Insomnia is not generally fatal, of course, because there are all kinds of self-preservation mechanisms that kick in. But unchecked sleep deprivation can actually kill. Laboratory animals subjected to extreme sleep deprivation die relatively swiftly of unknown causes — exactly what goes wrong is not clear, but their body temperatures start to drop and then they suffer rapid and widespread physiological failure. So sleep is actually required for life — for all life, in fact. Virtually every living organism sleeps, if it has any kind of a brain of any kind at all.

This strongly suggests that sleep-deprivation is potentially dangerous stuff, even when it isn’t lethal. A poison at a non-fatal dosage is still poisonous.3 And in fact there is a considerable amount of science confirming this general hypothesis. In his 1996 book, Sleep Thieves: An eye-opening exploration into the science and mysteries of sleep, Dr. Stanely Coren describes sleep deprivation studies in humans showing a number of ominous effects, and he generally makes a strong case that everyone needs to take sleep deprivation much more seriously than we generally do. Here are some other examples from much more recent scientific research:

So sleep deprivation involves some ominous potential hazards. But what about pain?

A personal example: acute sleep deprivation causes extra muscle soreness after sports (quite a lot extra)

Ultimate is an intense Frisbee sport that can make almost anyone wicked sore.

The first ultimates games of the season have always been an ordeal. They are followed by 3-5 days of harsh delayed-onset muscle soreness. But in 2011 I started the season in unusually good physical condition, thanks to months of sprint intervals and strength training. For the first time ever I was not sore after my first games of the summer. And my DOMS-immunity continued in week two, so it didn’t seem to be a fluke.

That was then followed by some nasty sleep deprivation and jet lag. I suffered a great of it for two weeks — before, during and after a holiday to Amsterdam. When I returned to Vancouver and played ultimate again, I was really blasted sore. Quite extreme!

Coincidence? I think not. The scientific evidence is strong that sleep deprivation and disruption are major factors in chronic pain. This is the best example I’ve observed in the laboratory of me!

Does insomnia cause pain generally?

Before trying to figure out if insomnia makes trigger points worse, a logical question to ask is: does it make any kind of pain worse? Yes, it probably does. “According to the majority of the studies, sleep deprivation produces hyperalgesic changes.”9 Here’s a fairly persuasive selection of the many available research examples:

In 2007, Smith et al experimentally messed with the sleep of 32 innocent women, and found that they were significantly more pain-sensitive, although in that case the effect was caused by sleep discontinuity, not deprivation alone (most insomniacs face both problems).10

An internet survey of over 2,500 people with fibromyalgia (a chronic pain condition) showed that insomnia was one of the most commonly identified aggravating factors.11 Whatever fibromyalgics find uncomfortable may be moving healthier people in the direction of increased sensitivity as well — they are a canary in the neurological mine. Simply put, if sleep deprivation does hurt, then fibromyalgics will notice it more readily than other people, and this is at least consistent with the fact that fibromyalgics believe that sleeplessness aggravates their symptoms.

Another survey found the fairly spectacular statistic that 53% of chronic low back pain patients had insomnia, compared with only 3% in pain-free controls.12 Critical thinkers will immediately suggest that it’s most likely that low back pain that is keeping these people awake, but I don’t think that’s obvious at all. The jury must remain out for me. My clinical experience suggests that it’s just the opposite: chronic low back pain patients are often poor sleepers, and insomnia may routinely precede episodes of pain! All of this is also discussed in advanced low back pain tutorial.

And fortunately I’m not alone in this fairly counterintuitive idea. Kundermann et al write, “Although it is well documented that subjects with different pain syndromes suffer from sleep disturbances, the direction of cause and effect in this relationship is still a matter of debate.”13



Do things really hurt more? Or does it just seem that way?

This is a very thorny question, almost a philosophical one. It is well agreed in pain science that “seeming” is the whole ball of wax, the only thing that really matters: if something seems painful, it is. But we can still observe that some seemingly painful things are associated with measurable changes in tissues, while other seemingly painful experiences seem to occur in the absence of any such changes, and this difference is obviously of interest, and we’d like to identify it if we can. For instance, we mostly know about trigger points because they hurt, but only relatively recently in medical history have we begun to identify the tissue changes associated with that pain!

The lack of such signs in the tissues does not indicate an imaginary or hysterical pain, but either that we simply can’t identify an associated change in the tissues, or the difference exists in the complex functioning of the central nervous system itself — not so much a pain that’s “all in the your head” in the psychological sense, but a pain that’s “all in your brain and spinal cord.”

And all pain is also mediated by psychology. There is no such thing as pain that is “all in your body” — it’s impossible. See Pain is Weird for more about that interesting idea.

In 2004, Kundermann et al tried specifically to approach this question of whether or not pain associated with sleep deprivation involves an “organic” change in the tissues, or is simply a differince how painful things seem. They tested whether or not sleep deprivation changed perception in general or only pain perception. The result was definitely the latter. Pain sensitivity was increased without any other general effects on physical sensations, strongly suggesting that something “actually” hurt more, as opposed to just “seeming” that way (“without alteration of somatosensation in general”).

The authors concluded, “Because this suggests an effect truly specific for pain, research may now focus on its underlying mechanisms of action.”14

Such as …

The case for insomnia as an aggravator of trigger points

Insomnia doesn’t just cause pain in general, and it doesn’t do it just by mucking with the volume of all your nerves. It also almost certainly causes musculoskeletal pain specifically. We’ve already given the examples of the effects on fibromyalgia patients and migraine sufferers. But insomnia is also a cause of increased muscle pain in normal, healthy people. This is getting awfully close to trigger points …

Moldofsky et al’s sleep deprived subjects “reported more musculoskeletal symptoms” and “a significant increase in muscle tenderness.”15 The same researchers repeated those results in a second study.16 In 1999 Lenssinck et al found in their sleep-deprived subjects a whopping “24% decrease in musculoskeletal pain threshold.”17 That’s tenderness in the muscles specifically — sensitivity to poking or “mechanical” stimualtion — as opposed to sensitivity to cold or heat as is the case in many of the studies mentioned previously.

Another sleep-deprivation study of nine men in 2001 showed that pain sensitivity increased 8% with a “sleep debt” of 40 hours (40 hours of lost sleep with no opportunity to recover). Even more interesting, letting them catch up actually had a much greater pain-relieving effect — “greater than the analgesia induced by level I analgesic compounds.” Cool!18

And so on.

We are still a long way from “proving” that insomnia affects trigger points specifically or directly. None of these studies even begin to try to correlate pain sensitivity and musculoskeletal symptoms with trigger points specifically. And how could they? A lot of the scientific know-how needed to reliably measure the presence and severity of trigger points is barely any older than this sleep research, and only a few people on Earth have it.

But there is plenty of reason here to make an educated guess that a lot of that increased sensitivity is related to trigger point formation. If we pull back from the science for a moment and think about our subjective experience, if we know that most pain and stiffness is caused by trigger points, then we also know that sleep loss makes them worse: who hasn’t had the experience of having a bad night and feeling distinctly stiffer, achier, more sensitive to pressure? Who hasn’t noticed that it is precisely such a morning when you are most likely to suffer from at least a tension headache, if not a migraine as shown in one of the studies mentioned earlier? Who hasn’t wished especially hard for a good shoulder squeeze after sleeping badly?

These common experiences are definitely consistent with trigger point aggravation. It is likely that there is a whole mess of physiology and psychology that produces those effects, numerous factors above and beyond trigger points alone. But it is also quite reasonable to imagine that the effect is dominated by a straightforward worsening of the same pain and stiffness caused by trigger points that we feel even when we’ve slept perfectly well. And this would be a good use of occam’s razor (Wikipedia) — let’s not make this too much more complicated than it has to be!

If insomnia does cause pain, the costs are even more serious

Can pain shorten your life? It’s a plausible and disturbing possibility.

A large Swedish study of four million Swedes looked for a correlation between increased mortality and work absenteeism due to painful musculoskeletal conditions.19 The costs of pain are often expressed in terms of hair-raising stats on the economics of work absenteeism — but they may be much greater still.They found the first ever evidence that people who have musculoskeletal pain may have “an increased risk of premature death.” The researchers adjusted their data for “several potential confounders.” The costs of pain are often expressed in terms of hair-raising stats on the economics of work absenteeism — but they may be much greater still.

Pain and insomnia are clearly the perfect ingredients not only of a vicious cycle, each one worsening the other, but potential a dangerous one. The stakes are high.

More personal perspective

I turned to a career in massage therapy in the late 90s largely because I was (and still am) an unusually “triggery” person. I am one of those people who just seems to have more than his fair share of trigger point discomfort. I relate well to my patients. I have been highly motivated to learn study the phenomenon of muscle pain.

In 2005, when I suffered from a particularly long and severe bout of insomnia, sleeping less than 4 hours per night for many weeks at a time, I experienced an inexorable increase in pain of all kinds, but especially trigger point pain. Every familiar old knot became loud and then vicious, and without question these sensations became the single most debilitating consequence of my insomnia.

Like Carl Sagan famously suggested, I try not to “think with my gut” and patiently wait for science to clarify the situation, one study at a time — it is okay to be uncertainmeanwhile. But if there is a topic in musculoskeletal health care that I have a “hunch” about, it’s this: insomnia is probably food for trigger points!

About Paul Ingraham

I am a science writer, former massage therapist, and assistant editor of Science-Based Medicine. I have had my share of injuries and pain challenges as a runner and ultimate player. My wife and I live in downtown Vancouver, Canada. See my full bio and qualifications, or my blog, Writerly. You might run into me on Facebook and Google, but mostly Twitter.

Notes

  1. Knutson et al. Association Between Sleep and Blood Pressure in Midlife: The CARDIA Sleep Study. Archives of Internal Medicine. 2009.

    Reduced sleep duration and quality are associated with elevated blood pressure, according to researchers with the CARDIA study. They used wrist activity monitors to monitor associations between sleep behaviors and BP among more than 500 adults in their 30s and 40s, finding that shorter sleep duration and poorer sleep maintenance were each associated with increased systolic and diastolic BP. The authors say the sleep-BP link is supported by previous research and “laboratory evidence of increased sympathetic nervous activity as a likely mechanism underlying the increase in BP after sleep loss.”

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  2. U.S. Department of Health and Human Services. Perceived Insufficient Rest or Sleep Among Adults — United States, 2008. Morbidity & Mortality Weekly Report. 2009. People unemployed or unable to work were at increased risk of sleep loss — likely due to the stress. And sleep insufficiency is most prevalent among those aged 25 to 34 and least among those 65 and older, which I think is also probably related to stress: people tend to suffer a lot more stress earlier in their careers. BACK TO TEXT
  3. Actually, many astute readers will know that this is crap: most medicines are toxic in high dosages, and many so-called “poisons” are actually used as medicines in low dosages. But this is a case of “you know what I mean” — a lot of sleep deprivation is a bad thing, and a smaller amount of sleep deprivation is still a bad thing, just less of it. BACK TO TEXT
  4. Alstadhaug et al. Insomnia and circadian variation of attacks in episodic migraine. Headache. 2007.

    This study of 1869 incidents of migraine clearly showed that “sleep obviously protects against [migraine] attacks rather than provokes them,” while a whopping 29% were actually caused by insomnia. I don’t know about you, but anything that protects against migraine attacks is good and I don’t want to lose much of it.

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  5. Akerstedt et al. Predicting long-term sickness absence from sleep and fatigue. Journal of Sleep Research. 2007.

    From the abstract: “… disturbed sleep and fatigue are predictors of long-term absence [from work due to sickness] and it is suggested that impaired sleep may be part of a chain of causation, considering its effects on fatigue.”

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  6. Ohayon et al. Place of chronic insomnia in the course of depressive and anxiety disorders. Journal of Psychiatric Research. 2003. BACK TO TEXT
  7. Neckelmann et al. Chronic insomnia as a risk factor for developing anxiety and depression. Sleep. 2007.

    The results of this very large and well-conducted survey are “consistent with insomnia being a risk factor for the development of anxiety disorders.”

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  8. Roth et al. Insomnia: epidemiology, characteristics, and consequences. Clin Cornerstone. 2003. PubMed #14626537. BACK TO TEXT
  9. Kundermann et al. The effect of sleep deprivation on pain. Pain Res Manag. 2004. BACK TO TEXT
  10. Smith et al. The effects of sleep deprivation on pain inhibition and spontaneous pain in women. Sleep. 2007. PubMed #17520794. BACK TO TEXT
  11. Bennett et al. An internet survey of 2,596 people with fibromyalgia. BMC Musculoskeletal Disorders. 2007. BACK TO TEXT
  12. Tang et al. Prevalence and correlates of clinical insomnia co-occurring with chronic back pain. Journal of Sleep Research. 2007. BACK TO TEXT
  13. Kundermann et al. Sleep deprivation affects thermal pain thresholds but not somatosensory thresholds in healthy volunteers. Psychosomatic Medicine. 2004. BACK TO TEXT
  14. Kundermann et al. Sleep deprivation affects thermal pain thresholds but not somatosensory thresholds in healthy volunteers. Psychosomatic Medicine. 2004. BACK TO TEXT
  15. Moldofsky et al. Induction of neurasthenic musculoskeletal pain syndrome by selective sleep stage deprivation. Psychosomatic Medicine. 1976. PubMed #176677. BACK TO TEXT
  16. Moldofsky et al. Musculosketal symptoms and non-REM sleep disturbance in patients with "fibrositis syndrome" and healthy subjects. Psychosomatic Medicine. 1975. PubMed #169541. BACK TO TEXT
  17. Lenssinck et al. The effectiveness of physiotherapy and manipulation in patients with tension-type headache: a systematic review. Pain. 2004. BACK TO TEXT
  18. Onen et al. The effects of total sleep deprivation, selective sleep interruption and sleep recovery on pain tolerance thresholds in healthy subjects. Journal of Sleep Research. 2001. PubMed #11285053. BACK TO TEXT
  19. Jansson et al. Sickness absence because of musculoskeletal diagnoses and risk of all-cause and cause-specific mortality: A nationwide Swedish cohort study. Pain. 2012. PubMed #22421427. BACK TO TEXT