The specific causes of chronic pain are often less important than non-specific sensitivity to any pain. Sometimes chronic pain has no specific cause at all, but even when it does, is rarely a tidy B-follows-A cause and effect relationship. Instead, the general conditions in which pain flourishes, the soils and fertilizers it likes — lots of other contributing factors — may be more problematic than whatever seems to be the “main” cause, even if it’s obvious (which is rare to begin with).
For instance, if the same minor structural problem with the spine seems to cause a lot of pain in some people, but little or none in many others, is it really a “spine” problem? The more basic issue is probably the underlying vulnerability to any kind of pain, which increases the risk of a minor glitch blooming into a chronic pain problem. Which is probably the case with most neck pain and back pain. Structural problems in the spine are seriously over-rated as causes.1 Of course they are important sometimes — just much less than people fear.2
This happens because pain is weird and tends to produce a lot of false alarms … and even more of them when your system is under strain.
This article explores the main modifiable risk factors for chronic pain, and the main ways of reducing it — get healthier! Which is easier said than done, but not as trite as it sounds either, and there is some relatively low hanging fruit like getting more active, and improving sleep quality. Does it work? No one knows for sure, but it’s highly plausible, and you also can’t really waste your time getting fitter.
So what are these non-specific vulnerabilities, specifically?
Sleep deprivation is one of the most obvious examples: everything hurts more when you lose too much sleep.3 Smoking is another classic, notable not so much because it’s bad for us — everyone knows that — but because it’s bad for pain,4 which most people do not know.
Another major example is being generally unfit and overweight — a known and significant risk factor for shoulder pain.5 The shoulder is not a weight-bearing joint, for the most part! The problem is with biochemistry that makes the tissues of the shoulder more vulnerable.
All the usual suspects are explored below, both biological and psychological — basically anything that we think of as unhealthy.
But it might not be specific! Or it may be effectively impossible to diagnose. Or it could be a general vulnerability to pain. Once you’re vulnerable, practically any specific problem can become a new source of torment, without really being the real problem. “The cause” is a web of interacting causes, many of them subtle and not obviously related.
Fighting complex non-specific causes of pain can feel like boxing with smoke, and it’s unlikely to cure any one case. But I suspect that it is a large part of the chronic pain puzzle, and a generally neglected opportunity to improve many tough cases. And in some cases of chronic widespread pain (“fibromyalgia”), a perfect storm of non-specific vulnerabilities might be the whole story — and trying to eliminate them might be the only hopeful treatment strategy available.
It is more important to know what sort of person has a disease than to know what sort of disease a person has.
The usual suspects: the classic non-specific, modifiable risk factors for chronic pain
There are several common modifiable risk factors for any kind of chronic pain that are typically neglected.6 Notice that they overlap extensively with misfortune, a hard life, and being out of shape.
- smoking, excessive drinking
- lack of exercise, a terrible diet, obesity, metabolic syndrome (all of which is virtually synonymous with chronic inflammation)
- stress, anxiety, depression, social isolation, discrimination, perceived poverty
- insomnia, which is probably king of all underestimated drivers of pain
- some common-ish nutrient deficiencies, most notably vitamin D and magnesium
- some drug side effects and complications that increase systemic sensitivity
These are all things you can change… in theory. With great difficulty, perhaps, but it’s possible.
If you’re suffering from almost any kind of chronic pain, it may make more sense to work on these bigger picture issues than it does to try to chase down specific causes. It’s difficult, of course. The big factors are often thoroughly entangled, all making each other worse.
For instance, an impoverished single mom, marginalized in countless ways by being queer, with a nasty ex-husband, a nicotine addiction, and looming diabetes is going to have more than just a “tough time” digging her way out of that mess. And yet it could still be the closest thing to real hope for that patient. Even when the ideal is nearly impossible to reach, steps in the right direction are almost always possible.
The realm of stress management is mostly about techniques to help deal with challenges that are less than disastrous. It is pretty effective in that sphere. But it just won’t work to generate a cult of subjectivity in which these techniques are blithely offered as a solution to the hell of a homeless street person, a refugee, someone prejudged to be one of society’s Untouchables, or a terminal cancer patient.
Why Zebras Don’t Get Ulcers, by Robert M Sapolsky, 405
How can nothing in particular make us hurt?
There are two main reasons:
First, because pain is weird. There are a lot of false alarms. The pain system is basically a threat-detection system — all pain is trying to warn you about something, and what is worthy of a warning is strongly affected by the brain’s highly unpredictable “opinion” of how much danger we are in. All of these things lower our brain’s threshold of concern, the level at which a give tissue threat is enough to bother our brains. When the threshold is lowered far enough for long enough, you have entered the strange and terrible land of sensitization, a disease of having too many false alarms, and too loud. Basically, pain “sensitization” is probably one of the ways that things like sleep deprivation make us hurt more.
In addition to general ways of fighting sensitization summarized here, there are also some more specific ways to do it, mainly avoidance and exposure. Those are discussed here: Sensitization in Chronic Pain.
Second, because systemic inflammation is a major mechanism for general vulnerability to pain, so virtually anything unhealthy can also dial that up, resulting in more intense and persistent signals from tissues. How much does a toe stub hurt? How many nerve impulses are sent to the brain? Well, definitely more if you are a little bit inflamed everywhere. Inflammation is one of the ways that sensitization actually happens — lots of overlap between these topics.
Lifestyle and metabolic factors are consistently associated with musculoskeletal pain (Rechardt et al). But tissue and structure are not. So why when patients don’t improve do we escalate tissue related treatments — e.g. injections, surgery — rather than lifestyle related treatments?
Chris Littlewood (@Prof_Littlewood)
How do you reduce a general vulnerability to pain?
When the primary complaint is pain, the treatment of pain should be primary.
Barrett Dorko, Physical Therapist, online discussion, 2010
It’s “easy:” improve your health! With a variety of vulnerability reduction projects, AKA “lifestyle medicine.” So not actually easy at all, but simple in principle. So simple it might seem like weak sauce.
If you really want to solve your chronic pain problem, then start making yourself as healthy as possible overall. Which is huge. Like any difficult, complex problem, you break it up into pieces and start with the easiest bits. It’s a long-term “pick your battles” challenge. More exercise and sleep deprivation are usually the lowest hanging fruit, and I make a few other suggestions, roughly in order of priority. And I recommend tackling these one at a time.
These aren’t “treatments” per se because none of these approaches is known to be good for any specific condition (except, perhaps, heart disease). However, they can all be considered “anti-inflammatory” to a some degree, because chronic low-grade inflammation is nearly synonymous with an unhealthy lifestyle.
Another way to think of it: this is the self-help version of multidisciplinary or multimodal pain management programs. Pain clinics have been doing basically this and growing in popularity for years.7 If you recruit professionals to help you with specific categories — a trainer, a nutritionist, a massage therapist, and so on — then there’s some more overlap with “real” multidisciplinary care.
Also, where’s the science? Does multidisciplinary care work, with or without a formal program? That’s a really tough question for this topic. See the final section of the article for some discussion of that — for now suffice it to say that it’s obviously complex, speculative, and I hope I have avoided anything that stinks of pseudoscience.
Warning! What could possibly go right?
The advice here may seem general to the point of being trite and useless, but that’s actually the point. Chronic pain patients understandably want specific answers, not vague platitudes and pep talks. But the point of this article is that “general answers” probably actually do matter… and they might matter a lot.
And what could possibly go right? You might not solve the pain problem, but you really cannot waste your time trying to be a healthier, fitter person!
Get more exercise
If you are badly out of shape, you could literally spend a decade learning how to be a more active and fit person. But you can start walking more tomorrow… and you can’t make a better, simpler investment in your health than just turning that dial a little bit. In fact, it’s downright startling just how efficiently walking delivers health benefits — much less than 10,000-steps/day is not only worth your while,8 but also less likely to cause an overuse injury. Do that first, get used to it, and then consider what comes next. Working up a sweat isn’t required, but five to ten minutes of it per day is a big upgrade from just walking — the returns start to diminish after that. Note that pumping a little iron offers incredible bang for buck and is by far the most underestimated and neglected exercise option among people who are gym-shy. Further reading:
- excessive sitting
- strength training and strength training frequency
Also, exercise is notably helpful with every other approach discussed here. For instance, it’s a critical way to help get more sleep…
Get more sleep
This is often a great place to start because it’s so common and so often an “unforced error,” caused entirely by poor “sleep hygiene” — the cumulative effects of many little things that disturb sleep. It’s even more important to work on sleep hygiene even when it’s not the main problem, like for people with sleep disorders, like sleep apnea, which are shockingly common. The more trouble you have with factors you cannot control, the more important it is not to neglect the factors you can control. See The Insomnia Guide: Serious insomnia-fighting advice from a veteran of the sleep wars.
Get less smoke
Quitting smoking has the biggest payoff of any clearly defined self-improvement project for patients with chronic pain. There is strong evidence that smoking is a major aggravating factor in chronic pain910 Smokers are about twice as likely to be in pain than non-smokers,11 even higher for headache, and triple the risk for spine pain. Smoking may partly explain why back pain becomes chronic in some people,12 and so likely neck pain as well.
Quitting is also the simplest thing on this list that you can tackle. But simple is not the same as easy, of course, and beating a nicotine addiction is incredibly difficult for many people — so stressful that it can interfere with everything else. On the other hand, not everyone finds it crazy hard to get rid of nicotine. Advice on smoking cessation is out of the scope of this website. But I have written about its relevance to chronic pain, which may help to inspire you: see Smoking and Chronic Pain: We often underestimate the power of (tobacco) smoking to make things hurt more and longer.
Eat an anti-inflammatory diet
… which is mainly just a non-stupid diet that isn’t obviously hurtling you towards obesity, heart disease, and diabetes (metabolic syndrome). No one knows exactly what a non-stupid diet is, but we know it when we see it, because it’s obviously characterized by moderation, and you don’t eat like a teenager. The booze is minimal, the portions are rarely super-sized, you drink more water than soft drinks, there’s not much deep fried, and very little of the food is fast. It’s not about superfoods or antioxidants or supplements or “paleo.” This self-improvement project is a lot harder than it sounds, and it’s very unclear how much it will help with any chronic pain proble. But the best thing about it? You cannot waste your time on this: it’s worth doing even if it has exactly zero effect on whatever specific pain problem you have.
Or you could try not eating: fasting as an anti-inflammatory diet
The most anti-inflammatory diet of all could be intermittent fasting — regularly skipping some meals basically — which induces some interesting metabolic changes that might contribute significantly to overall health,13 in part by reducing systemic inflammation.14 It’s suspiciously trendy and unproven,15 but also plausible, practical, and reasonable, and perfectly good as a weight-loss diet if nothing else. See Chronic, Subtle, Systemic Inflammation for a more in-depth analysis.
And again, it may not be that fasting is anti-inflammatory, but rather that long-term overeating is inflammatory.
This is probably the most useless-but-important advice I ever give on PainScience.com. Stress reduction is probably the ultimate in “easier said than done” challenges. It truly matters, but the things that cause stress are often totally out of our control, or insanely difficult to control. If they weren’t, they wouldn’t be serious sources of stress in the first place.
For instance, a career change might be your only real hope of significantly reducing stress in your life… which might require going back to school, which you can’t afford… and so on. This challenge needs to be subdivided into smaller challenges.
Take the possibility of an actual anxiety disorder very seriously. If you think your worries are both severe and chronic, addressing that should be a priority. Health anxiety in particular is extremely corrosive.
For more ideas, see Anxiety & Chronic Pain: A self-help guide for people who worry and hurt. And don’t get hung up on yoga and meditation. Reducing stress is mostly about doing your best to solve life problems, not about trying to transcend them. And exercise, while not a perfect solution for everyone, is almost certainly the best overall single medicine for stress and anxiety (and much else).1617
The biology of vulnerability to depression is that you don’t recover from stressors very well.
Why Zebras Don’t Get Ulcers, by Robert M Sapolsky, 307
Make more friends
Social isolation, AKA “loneliness” for those who are unhappy with being isolated,18 is a major general health suppressor in the same league as anxiety and chronic stress, sedentariness, smoking, sleep deprivation, and metabolic syndrome.19 It almost certainly involves increased vulnerability to chronic pain as part of the deal, and some evidence definitely suggests this.20 We do know that sensitization and pain chronicity are driven by catastrophization and social factors, and injury and disability are always going to be more of a threat — more “catastrophic” — to people without good social support, or the opportunity to be supportive. Giving support is just as stress-relieving as getting it. In other words, you have more to worry about and less to do when you’re lonely.
Obviously it can be tough to get out there and interact with new people. It could be even more more stressful at first.21 The effort might make loneliness worse — or feel worse — before it gets better, because loneliness is hardest to escape for the people who need it the most. But it’s a worthwhile investment.
If you’re so isolated and lonely that improvement feels truly impossible, it might be time to get some professional help with that. And if that feels impossible or unaffordable, then tackle it the only way anyone ever solves a tough problem: baby steps! Pick the easiest way of getting more social contact that you can possibly imagine, and start there.
Make more money
Money does not buy happiness, but perceived poverty is crazy stressful. Why “perceived”? Because we don’t really care how much money we have — we care how much everyone else has. It’s not our absolute level of affluence that concerns us, but how affluent we are compared to the rich bastards all around us. It’s feeling like we are on the outside of something good, enviously looking in, that really eats away at our happiness.
The best defense is a good offense: to whatever extent possible, get better at the rat race. Or move somewhere a lot cheaper.
A lifelong project
Collectively, tackling all of this would constitute a total personal makeover. You could spend the rest of your life working on it, just growing up and trying to be a better person overall, and who knows if any of it is actually going to change your chronic pain — tragically, it might not, because there are many, many causes of pain.
Or maybe your pain will finally go away, but you’ll never know if it was because you finally started eating better and working out a little more.
But if we could somehow compare a thousand people with pain who really made a sincere effort to increase their overall immunity to chronic pain, to a thousand who didn’t… I know which group I am betting on.
The best evidence for treating persistent pain points towards improving general health, as opposed to fixing specific “issues in the tissues.”
Playing With Movement, by Todd Hargrove, p. 217
Where’s the evidence? Does this approach to pain work?
I frankly have no idea. It is not based on evidence, because it can’t be, not directly — it’s just too big and fuzzy. For starters, look at the premise for the whole thing: what is the evidence that things like being generally unhealthy and sleep deprived and stressed are actually risk factors for chronic pain in the first place?
The right kind of research to answer this would be large, prospective studies. That is, research that tracks healthy people over time to see who gets chronic pain and what those people have in common. Does that evidence exist?
The most evasive/defensive answer is that there’s an absence of good evidence for good reasons: tricky, expensive research, many variables that are hard to control, and so the claim is based on reasonable inference from indirect evidence. Probably the best example of the indirect evidence comes from sleep science, which is quite clear that sleep deprivation is probably a risk factor for pain, although even that evidence is limited,22 and in any case sleep is only one piece of this puzzle.23
The most candid answer is that the good evidence that poor overall health leads to pain simply doesn’t exist, and it should, and it’s a shame. There is a mountain of indirect evidence… but it’s not really the evidence we need to answer this question properly.
Consider just a single sub-topic: the challenge of “proving” that psychological stress is unhealthy, a topic Dr. Sapolsky covered exhaustively in Why Zebras Don’t Get Ulcers (highly recommended).24 No one who reads that book has much doubt that stress is unhealthy by the time they put it down… but it’s all based on a complex consilience of inadequate and indirect evidence.
And so, for now, we have to go with something that looks more like a hunch than good science.
And how about lifestyle medicine as a treatment? That is no easier. Complex non-specific interventions are also extremely hard to study25 and this one is so gnarly that it’s effectively impossible.
I would certainly never presume to believe that any complex treatment for pain is effective based only on my own speculation and experience. “One-size-fits-all/most” treatments for chronic pain are impossible in principle: its causes are too diverse, and include many intractable pathological causes that can disable perfectly healthy people.
What I hope I am recommending is solid science-based speculation. I hope I haven’t made any unreasonable leaps of logic or leaned on any pseudoscientific premises. It would have been super easy to slip into promoting something sketchy. How many popular but bizarre ideas are there about what constitutes a healthy lifestyle? Dozens at least, many hundreds if you include more obscure crankery. My job here was mostly about excluding that garbage: nothing about “paleo,” no superfoods, no warnings about the dangers of electromagnetic radiation, and so on.
About Paul Ingraham
I am a science writer in Vancouver, Canada. I was a Registered Massage Therapist for a decade and the assistant editor of ScienceBasedMedicine.org for several years. I’ve had many injuries as a runner and ultimate player, and I’ve been a chronic pain patient myself since 2015. Full bio. See you on Facebook or Twitter, or subscribe:
- 34 Surprising Causes of Pain — Trying to understand pain when there is no obvious explanation
- Anxiety & Chronic Pain — A self-help guide for people who worry and hurt
- Sensitization in Chronic Pain — Pain itself can change how pain works, resulting in more pain with less provocation
- Pain is Weird — Pain science reveals a volatile, misleading sensation that comes entirely from an overprotective brain, not our tissues
- Mind Over Pain — Pain can be profoundly warped by the brain, but does that mean we can think the pain away?
- Chronic Pain as a Conditioned Behaviour — If pain can be learned, perhaps it be unlearned
- The 3 Basic Types of Pain — Nociceptive, neuropathic, and “other” (and then some more)
- Pain Relief from Personal Growth — Treating tough pain problems with the pursuit of emotional intelligence, life balance, and peacefulness
What’s new in this article?
Nine updates have been logged for this article since publication (2019). All PainScience.com updates are logged to show a long term commitment to quality, accuracy, and currency. more
When’s the last time you read a blog post and found a list of many changes made to that page since publication? Like good footnotes, this sets PainScience.com apart from other health websites and blogs. Although footnotes are more useful, the update logs are important. They are “fine print,” but more meaningful than most of the comments that most Internet pages waste pixels on.
I log any change to articles that might be of interest to a keen reader. Complete update logging of all noteworthy improvements to all articles started in 2016. Prior to that, I only logged major updates for the most popular and controversial articles.
See the What’s New? page for updates to all recent site updates.
Oct 24, 2021 — Science update. Added a citation to Sheng et al about the excellent fitness bang-for-buck delivered by walking.
2020 — Editorial polishing.
2020 — Science updated. Added a good example from Rechardt et al.
2020 — Added and discussed one of the only examples of evidence that can, at least in principle, show a causal link between poor health and chronic pain.
2020 — Added a discussion of the evidence, such as it is. Also, extensive editing and polish.
2020 — Added an article summary (which inspired a bunch of editorial improvements to the article, as it summarizing always does).
2020 — Still more editorial polish and clarifications — nothing major, but another upgrade. I just keep revisiting the topic this week.
2020 — Another round of significant editing. I added a few clarifications, elaborations, and references.
2020 — Added a section, “Where’s the evidence? Does this approach work?” Plus some miscellaneous editing.
2020 — Added some quotes and context from Sapolsky on the stresses of combatting loneliness, and the intractability of severe stresses.
2019 — Publication.
- A Rational Guide to Fibromyalgia — The science of the mysterious disease of pain, exhaustion, and mental fog
- Chronic Pain and Inequality — The role of racism, sexism, queerphobia, and poverty in health and chronic pain
- Sensitization in Chronic Pain — Pain itself can change how pain works, resulting in more pain with less provocation
- Pain is Weird — Pain science reveals a volatile, misleading sensation that comes entirely from an overprotective brain, not our tissues
- Pain Relief from Personal Growth — Treating tough pain problems with the pursuit of emotional intelligence, life balance, and peacefulness
- Pain & Injury Survival Tips — Dozens of ideas (and links) for evidence-based rehabilitation and self-treatment for common pain problems and injuries
Around the web…
- “A Systems Perspective on Chronic Pain,” Todd Hargrove, BetterMovement.org. This deep but beautifully readable article explains, with many pictures and apt examples, how “chronic pain is often driven by dysregulation of a ‘supersystem’ that coordinates defensive responses to injury. The supersystem results from dynamic interaction between different subsystems, most notably the nervous system, immune system, and endocrine system.” The article also manages to make this information seem quite practical, believe it or not.
- “Evolution, Stress and Fibromyalgia,” John Quintner, FMperplex.com.
- “Fibromyalgia and Neuroinflammation: Shall the Twain Ever Meet?,” John Quintner, FMperplex.com.
- This is known as the “injury model” of pain, or “structuralism,” especially with regards to back pain, where the dichotomy of specific versus nonspecific is at its most glaring. It has long been clear that an “injury model” cannot explain the majority of back pain (see Vlaeyen et al). Instead, it seems to emerge from a witch’s brew of many risk factors, complications, and positive feedback cycles.
This article promotes the importance of non-specific causes and approaches to managing chronic pain, but of course this doesn’t mean we should neglect the search for specific problems: it all matters. The injury model fails to explain a lot of chronic pain all the time, but that doesn’t mean it’s always misguided.
I am fascinated by stories of “baffling” pain that eventually get tidy explanations; I have one of my own, a serious and mysterious chronic throat pain that had got an extremely specific and successful solution.
Like a computer bug, these problems are only baffling until you finally figure it out, and then it’s like, “Well, there’s your problem,” obvious once you know.
But there’s no reason not to explore non-specific causes and complications of pain, and that’s what this article is about.
- Almost everyone needs to take sleep deprivation more seriously. We are used to thinking of insomnia as a symptom, but it can also be hazardous in itself in many ways. Chronic pain is probably aggravated by insomnia or even mild but chronic sleep deprivation. For more information, see Insomnia Until it Hurts: The role of sleep deprivation in chronic pain, especially muscle pain.
- Smuck M, Schneider BJ, Ehsanian R, Martin E, Kao MC. Smoking Is Associated with Pain in All Body Regions, with Greatest Influence on Spinal Pain. Pain Med. 2020 Sep;21(9):1759–1768. PubMed #31578562 ❐
Researchers analyzed survey data for 2300 Americans from 2004, looking for the relationship between smoking and pain and finding strong links. Smokers had close to a three times greater risk of spinal pain than non-smokers, with headache almost as bad. Most other kinds of pain were around twice as likely to occur in smokers.
- Rechardt M, Shiri R, Karppinen J, et al. Lifestyle and metabolic factors in relation to shoulder pain and rotator cuff tendinitis: a population-based study. BMC Musculoskelet Disord. 2010 Jul;11:165. PubMed #20646281 ❐ PainSci #51846 ❐
- Citation needed? Certainly! But “it’s complicated.” I dig into the science a bit in the last section of the article.
- Hylands-White N, Duarte RV, Raphael JH. An overview of treatment approaches for chronic pain management. Rheumatol Int. 2017 Jan;37(1):29–42. PubMed #27107994 ❐
Pain which persists after healing is expected to have taken place, or which exists in the absence of tissue damage, is termed chronic pain. By definition chronic pain cannot be treated and cured in the conventional biomedical sense; rather, the patient who is suffering from the pain must be given the tools with which their long-term pain can be managed to an acceptable level. This article will provide an overview of treatment approaches available for the management of persistent non-malignant pain. As well as attempting to provide relief from the physical aspects of pain through the judicious use of analgesics, interventions, stimulations, and irritations, it is important to pay equal attention to the psychosocial complaints which almost always accompany long-term pain. The pain clinic offers a biopsychosocial approach to treatment with the multidisciplinary pain management programme; encouraging patients to take control of their pain problem and lead a fulfilling life in spite of the pain.
- Sheng M, Yang J, Bao M, et al. The relationship between step count and all-cause mortality and cardiovascular events: A dose-response meta-analysis. J Sport Health Sci. 2021 Sep. PubMed #34547483 ❐ PainSci #52202 ❐
This study shows that the health benefits of walking are both amazingly large and also “non-linear”: that is, you get a lot of benefit up front, a huge reduction in health hazards by the time you’ve hit 5K steps/day… at least double what you get out of the next 5K. The ten-thousand-steps “rule” is overkill for a lot of people.
(See more detailed commentary on this paper.)
- Choi CJ, Knutsen R, Oda K, Fraser GE, Knutsen SF. The association between incident self-reported fibromyalgia and nonpsychiatric factors: 25-years follow-up of the Adventist Health Study. J Pain. 2010 Oct;11(10):994–1003. PubMed #20400378 ❐ More smokers have fibromyalgia than non-smokers. The difference was statistically significant in a survey of more than 3000 women.
- Behrend C, Prasarn M, Coyne E, et al. Smoking Cessation Related to Improved Patient-Reported Pain Scores Following Spinal Care. J Bone Joint Surg Am. 2012 Dec 5;94(23):2161–6. PubMed #23095839 ❐
This study added to the pile of evidence that smoking is “associated with low back pain, intervertebral disc disease” along with many other medical complications. Their conclusion, after studying the records of more than 5000 patients with “axial or radicular pain from a spinal disorder,” was that there is a “need for smoking cessation programs for patients with a painful spinal disorder.” Very likely both neck and back, of course.
- Smuck 2020, op. cit.
- Petre B, Torbey S, Griffith JW, et al. Smoking increases risk of pain chronification through shared corticostriatal circuitry. Human brain mapping. 2014 Oct. PubMed #25307796 ❐
The science here is a bit more complex than I usually deal with, but the punchline is simple enough: “We conclude that smoking increases risk of transitioning to chronic back pain.”
- de Cabo R, Mattson MP. Effects of Intermittent Fasting on Health, Aging, and Disease. N Engl J Med. 2019 12;381(26):2541–2551. PubMed #31881139 ❐
- Jordan S, Tung N, Casanova-Acebes M, et al. Dietary Intake Regulates the Circulating Inflammatory Monocyte Pool. Cell. 2019 Aug;178(5):1102–1114.e17. PubMed #31442403 ❐
- The “growing body of evidence” has been exaggerated by everyone (surprise surprise), and fasting has not yet been shown to be “anti-inflammatory” per se. As of mid 2021, there is quite literally only one good modern study showing clear evidence of an anti-inflammatory effect in humans. Nevertheless, there is a lot of indirect evidence, things like animal and cellular research, and some evidence that fasting improves autoimmune diseases.
- Schuch FB, Stubbs B, Meyer J, et al. Physical activity protects from incident anxiety: A meta-analysis of prospective cohort studies. Depress Anxiety. 2019 Jun. PubMed #31209958 ❐
This meta-analysis links high levels of activity to lower rates of anxiety. Many people who exercise will still develop anxiety, but 26% less often than sedentary people. The authors focused on 13 studies with “moderate to high methodological quality and a low risk of bias” with a huge total sample size of 76,000 people, and they made adjustments to eliminate the effect of gender, BMI, and smoking (in other words, they tried to make sure that observed effects were actually due to the activity level, and not those factors).
The simple headline “exercise helps anxiety” could describe the results of this study, and it wouldn’t be a completely unreasonable oversimplification, but the details are devilish as usual, and it’s actually not such a clear win. With such a huge pool of data to play in, the authors decided to break it down into several different types of anxiety, and found that the results were statistically significant only for PTSD and agoraphobia… and not generalized anxiety and a few others. Although activity seemed to help all types of anxiety, there was not actually enough data here to be sure in most cases — a data pie of 76,000 subjects seems big, but it can easily be sliced into pieces too thin to trust. It’s likely that exercise does help most types of anxiety, but it’s hard to actually know it from this data.
And this is why science is slow to be sure of much of anything squishy and complicated.
- Pedersen BK, Saltin B. Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases. Scand J Med Sci Sports. 2015 Dec;25 Suppl 3:1–72. PubMed #26606383 ❐
This is s a roundup of evidence and prescription guidelines for prescribing exercise for many (26!) different diseases, which is not to say that the science is necessarily complete and perfect. Consider the nuance in Schuch, which found good overall evidence that exercise protects people from “anxiety,” but — despite a huge sample size — could only actually report statistically significant results for a couple specific types (PTSD and agoraphobia). So does exercise work for anxiety? Likely, but “it’s complicated,” as always.
Still, it’s hard not to be impressed by the sheer volume and diversity of the evidence inspiring these authors.
- “Lonely” is a negative emotion by definition, but not everyone is unhappy about being socially isolated. A “loner” might be just fine with their social isolation.
- Sapolsky RM. Why Zebras Don’t Get Ulcers. 3rd ed ed. New York: Times Books; 2004. p. 164. “…the fewer social relationships a person has, the shorter his or her life expectancy, and the worse the impact of various infectious diseases. Relationships that are medically protective can take the form of marriage, contact with friends and extended family, church membership, or other group affiliations. This is a fairly consistent pattern that cuts across a lot of different settings. Moreover, these general findings are based on some careful prospective studies and are seen in both sexes and in different races, in American and European populations living in both urban and rural areas. Most important, this effect is big. The impact of social relationships on life expectancy appears to be at least as large as that of variables such as cigarette smoking, hypertension, obesity, and level of physical activity.”
- Smith TO, Dainty JR, Williamson E, Martin KR. Association between musculoskeletal pain with social isolation and loneliness: analysis of the English Longitudinal Study of Ageing. Br J Pain. 2019 May;13(2):82–90. PubMed #31019689 ❐ PainSci #52275 ❐
This study looked for a link between chronic musculoskeletal pain, and loneliness and social isolation in several thousand older adults. They found that subjects in pain were actually less likely to be socially isolated, but more likely to be lonely, an interesting apparent contradiction. However, loneliness is probably what matters: that is, social isolation isn’t a problem if you don’t feel socially isolated (lonely).
- Sapolsky, Why Zebras Don’t Get Ulcers, op. cit.
Take a rodent or a primate that has been housed alone and put it into a social group. The typical result is a massive stress-response. In the case of monkeys, this can go on for weeks or months while they tensely go about figuring out who dominates whom in the group’s social hierarchy.
Why Zebras Don’t Get Ulcers, by Robert M Sapolsky, 406
- Nitter AK, Pripp AH, Forseth KØ. Are sleep problems and non-specific health complaints risk factors for chronic pain? A prospective population-based study with 17 year follow-up. Scand J Pain. 2012 Oct;3(4):210–217. PubMed #29913872 ❐
This is a true prospective study of sleep deprivation as a risk factor for pain, following the fate of more than 1300 women over 17 years. Although one study is never enough to truly settle anything, it is an example of the right kind of evidence to establish causality. This research did not just present evidence that sleep deprivation and chronic pain are linked (as many other studies have done), but that sleep deprivation actually caused chronic pain.
Its weakness is that the data itself was not especially high quality: just three very widely-spaced surveys. There was no objective data involved at all, just self-report. Thus, despite its useful prospective design, it hardly proves that being sleep deprived will cause a chronic pain problem. It just “suggests” it.
No matter how high quality the evidence that it leads to pain, it doesn’t necessarily mean that health status in general leads to chronic pain. It’s certainly suggestive.Actually, Nitter et al did also look at “health complaints” — the other pieces of the puzzle — and found that they were also a risk factor for chronic pain. It just doesn’t count for much, because the data was so thin.
- Sapolsky RM. Why Zebras Don’t Get Ulcers. 3rd ed ed. New York: Times Books; 2004. A fascinating, charming tour of stress science. Although it is detailed to a fault in places, Sapolsky’s attempt to make it palatable is downright heroic. The book’s main lesson is that stress is definitely a serious health issue, though “it would be utterly negligent to exaggerate the implications of this idea.” Humans have a unique capacity to react to imagined threats — psychological stress — but we differ dramatically in our vulnerability to them. To some extent that vulnerability can probably be managed, but “it’s complicated.” To the extent that we can reduce stress, “80 percent of the stress reduction is accomplished with the first 20 percent of effort.” (Curiously, this book is cited or quoted more than any other single source on PainScience.com: Sapolsky is referenced almost 200 times in about three dozen articles.)
And this idea of an everything-but-the-kitchen-sink approach to chronic pain, of trying to address multiple overlapping factors in general health, is the ultimate in “complex non-specific.” In theory, studying it properly would require many huge prospective cohort studies to get anywhere. In practice, it’s effectively impossible.
It’s drawing on several major areas of health science, each of which is independently so difficult that there is no end in sight to their controversies. For instance, nutrition science: hopelessly mired in complexity! And yet it’s just one component of what I’m talking about here.