Episode 3: Does Chronic Stress Increase Chronic Pain?

Our results show that there is a significant relationship between people experiencing high work stress and chronic pain. This finding asks the following questions: Does chronic stress increase chronic pain? Could lowering individual stress levels help reduce the experience of chronic pain?

Why are we so stressed?

For most of our species’ history, the environment in which most humans existed was one punctuated by extreme stressors, many of which had life and death consequences. We evolved to respond effectively to stress - in order to stay alive long enough to reproduce and raise kids. We didn’t evolve to minimise negative experiences just because they’re not fun.

Over millennia, we’ve learned to control our surroundings.  Now most people, especially in wealthy countries, are lucky enough to live in a far safer and less uncertain environment. Surely this means that, for most, stress should be a thing of the past - like dying from minor injuries, starvation or animal attacks?

Of course this hasn’t happened. Despite our more certain environment, our bodies and minds respond to objectively milder perils - like social or financial stress - as if they were literally existential, somewhat pointlessly readying us to fight for our lives on the savannah. We’ve simply switched our attention to the things we still can’t fully control (which are often more constant because they are less intense), and we get stressed about that instead.

Good stress and bad stress

The perception of stress is, as you might expect, incredibly useful. Like pain, stress is a powerful motivator for us to take action. We often forget that when our bodies and brains are operating in an ideal way, the experience of stress serves to protect us - motivating us to perform at our mental and physical maximum. Short term bursts of stress can also have a protective effect on the way potentially stressful events are viewed - and can ‘desensitise’ us to things that might otherwise cause anxiety. In many respects, stress is like exercise: higher intensity bursts, with rest and recovery periods in-between, is the healthy ideal. 

But when stress is unrelenting, we are not able to resolve or control the events causing it and our response to stress becomes in itself harmful, rather than healthy. Our bodies cannot sustain a level of high alert for long periods without detrimental consequences. This is chronic stress and it reduces our immune response, diminishes brain cell growth, limits our ability to use information effectively, accurately assess risk, and over the long term is associated with accelerated cognitive decline and risk of dementia.

Modern stressors tend to involve less jeopardy than the stressors we faced in our species’ history, and this means they tend to be less punctuated, more constant. Ally this to the fact that we treat this lower jeopardy exactly the same as if we are under extreme physical threat and what should have been great for us all - a real reduction in life threatening risk - has actually turned out pretty badly for a lot of humanity.

Reduce stress, reduce pain?

What is the relationship between chronic stress and chronic pain? In the medium term, chronic stress sensitises us to negative outcomes, reduces our risk taking behaviour (and hence our tolerance of uncertainty) and increases our production of (ultimately inflammatory hormone) cortisol. All of these can increase chronic pain. 

Over the longer term, chronic pain and chronic stress can result in long lasting changes to how the brain and nervous system work, in a process referred to as central sensitization. This results in a nervous system that is in a constant state of hyperstimulation.

As part of its ongoing work into the perceptual sources of chronic pain (in collaboration with Stop Chasing Pain), we looked at geographical data on stress in the US, targeting work related stress, precisely because it creates the kind of non-life threatening, constant stress that we’ve seen can be so harmful. Alaska, Hawaii and Nevada were the most work-stressed, and Utah, South Dakota and Idaho the least. When we compared this data to the location of the American responses we got on chronic pain, we found a relationship: The higher up the US state in its stress rankings - specifically work related stress - the higher the reported level of chronic pain from that state.

The finding is especially interesting because it’s an average work-stress measure within each state. This suggests that there are large scale policies that businesses and societies could enact to reduce stress (and hence possibly chronic pain, which we know impacts the lives of a huge number of adults).

As before, we don’t know from our data alone if the relationship is causal - but what we know about the link between stress and pain suggests that it is. There are many techniques to lower our individual stress levels - especially if we focus attention on one area, like work. Could this help reduce the experience of chronic pain?

What does this tell us?

How can we, as individuals, apply these insights to our own lives?

When you’re stressed, just about the last thing that it feels natural to do is observe how you’re feeling - you’re too busy fighting whatever fire has gotten you stressed in the first place. But if it’s possible, it’s good to remind yourself that your pumping heart, the shots of adrenaline you feel, the butterflies in your stomach (caused by blood being diverted from non-urgent digestion to your muscles, to prime them to fight or run) is an evolutionary response that is probably not that helpful if you’re in a traffic jam late for a meeting. Your body is preparing for something that is never going to happen. It’s kind of ridiculous.

Secondly, “what really IS the worst that can happen?”. If the thing you’re scared of happening happens - will you die? Or does life continue pretty much as before, with some minor added hassle or imperfection? Rather than see the outcome with a ‘binary mindset’, try to see the outcome more objectively, and on a scale. Doing so will help you assess the real risk involved rather than starting the cycle of panic > heightened risk perception > exaggerated physical response > more panic.

What about chronic, low level stress? That feeling of permanent anxiety in your peripheral consciousness. The best advice is don’t accept it as if it’s normal. It’s not. The feeling itself is bad for you (quite apart from whatever it is - that may or may not happen - making you feel that way). Help with chronic stress can take many forms including sleep, exercise, generosity towards others, but the key thing to do is recognise it’s happening and take positive proaction. 

All these approaches share one underlying thing which we’ve mentioned many times in these blogs: they require you to activate your prefrontal cortex, to observe yourself respond to situations - to see yourself see - and in doing so be able to make a choice. A sense of one’s own agency and control is a powerful way to reduce negative stress, and as our experiments suggest, may even help reduce experience of chronic pain.

If you haven't taken part in the Map of Pain experiment, you still can. Click here to participate.

Written by: Richard Clarke and Beau Lotto.