Fibromyalgia and Cold Intolerance

With winter on the way, I thought it would be a good idea to talk about cold weather and Fibromyalgia, or more simply put, Fibromyalgia and cold intolerance. There was once a time no one had heard of Fibromyalgia, unfortunately, it is now a much more common condition,  seen in around 2% of the population. While this not may seem like much, that’s around 160 million people who are affected by Fibromyalgia. That’s almost 3 times the size of the population of the united kingdom.    

Cold intolerance is defined as an abnormal sensitivity to a cold environment or cold temperatures. Now, when it comes to Fibromyalgia and the cold, it’s not all about shivering. In fact, in some cases, you can experience fatigue and even depression, alongside higher levels of anxiety and feeling colder than the temperature actually merits.  Cold intolerance isn’t regarded as a disease in its own right, but more so a symptom of another condition. In a lot of cases, it’s thought that cold intolerance can be predicted, such as the highly reported cold intolerance in upper limbs, following surgery.  There are a lot of unknowns when it comes to cold intolerance and the evidence we have shows that more research is needed, and as usual, adding Fibromyalgia into the mix can make it even more complicated.

One population study found that the prevalence of cold intolerance among Thai poultry industry workers was a whopping 76%. However, there is a pretty strong correlation between cold exposure for these workers and cold intolerance. The problem we have though is that most people with Fibromyalgia, simply aren’t spending a lot of time in places of temperatures around -20 to -23degrees. 

So what’s going on?

Do those with Fibromyalgia have an intolerance to the cold?

The research on Cold intolerance and Fibromyalgia isn’t decisive, it doesn’t simply state that if you have Fibro you’ll suffer when cold. Some people are affected yes, but another group may be totally fine. So, let’s take a look at the research into fibromyalgia and cold.

One study looking at the link between Fibtomaylgia pain and weather, used daily weather forecasts and questionnaires to see if there was any correlation to increases in pain. Another aim of this study was to find if physiological influences with the weather had any impact on pain. In short, absolutely no change. Temperature, relative humidity, solar flux, and psychological variables influencing the weather–pain interaction, found no prediction of pain increases. However, there were some interesting correlations with Barometric pressure, however, nothing significant. This study determined that the evidence for strong weather–pain association in those fibromyalgia seems limited at best.

A chance discovery, finding that those with Fibromyalgia had extra temperature-sensing nerves called AV shunts, focused new research. AV shunts (Arteriole-Venule Shunts), help to regulate blood flow to the skin for temperature regulation, and it has been hypothesised that those with Fibromyalgia may experience blood flow dysregulation causing pain.

In a study published in the clinical journal of pain, researchers tested for sympathetic responses to temperature stimuli in those with Fibro. They monitored skin temperature, thermogenic activity, circulating glucose and pain. In this study, 13 of the participants were diagnosed with Fibromyalgia, and a control group was made up of 11 people who didn’t have a Fibromyalgia diagnosis.

When measuring stimuli at room temperature there was no difference between the control group and the Fibromyalgia group. However, when it came to the cold stimuli, brown adipose tissue activity increased in controls, more than in the Fibro group, however, the circulating glucose was lower in those with Fibromyalgia. A good point to note here is that females are far less able to recruit brown adipose tissue in response to chronic stress than their male counterparts. This is important when we look at just how high the prevalence of Fibromyalgia is in women, compared to men. Many conditions that come with Fibro, can compromise brown adipose activity, making it less responsive to stressful stimulation. This often manifests as lower body temperature, lower metabolic rate, and lower circulating cortisol. Which has led researchers to believe, that the sympathetic nerves that lead to brown adipose tissues and surrounding tissues, may infact be the reasons for some of the pain associated with Fibro.

What makes this study particularly interesting, is that pain sensitivity did not change. This shows that those with Fibromyalgia, most likely have an impaired sympathetic response to stress. Now, this isn’t a fantastic study, as it’s just not a very large sample size, but it most certainly gives us some insight.

Another study, published in the journal of pain, Is somewhat better with a slightly larger group. Researchers tested 51 people for their response to temperature stimuli. 23 who had Fibromyalgia and 28 healthy controls. It found that those with Fibromyalgia were not only more sensitive to noxious stimuli. but also to sound, suggesting that hypersensitivity is not just limited to physical stimuli. This does back up a lot of other studies in which we find issues like light sensitivity or photophobia is much more prevalent in the Fibro community than in the general population at 70% and 6% respectively.

But, as is the case with a lot of Fibromyalgia studies, there are a lot of variables that don’t get accounted for. In this study, it was the fact that those participating, were tapering off pain & antidepressant medications prior to starting. If there was ever a variable that’s likely to affect research, it’s definitely this.

A more contradictory study, found in the journal of musculoskeletal pain, blurs things a little. This study got rid of our medication issue in the last study. What they discovered was that there was a noticeable increase in pressure sensitivity, a moderate increase in electrical stimuli sensitivity, but a largely normal sensitivity to heat stimuli. This suggests that Fibromyalgia is not a simple condition of multi-modal hyperalgesia.

A systematic review into the influence of temperature on Fibromyalgia pain, 13 studies, 9 of which found no easily established relationship between temperature and Fibro pain. However, 35 QST (quantitative sensory testing) studies, which is a method used to assess sensory system functioning, were used and 17 of those assessed Cold pain threshold. This showed evidence that was statistically significant in 14 of the 17, showing an abnormal sensitization of the temperature sensation systems. So much so, that some research has looked into alpha 2-adrenergic receptors, hypothesising that a subgroup of patients with fibromyalgia syndrome has an up-regulation of alpha 2-adrenergic receptors causing their exaggerated reaction to cold.

Another Systematic review & Meta-Analysis, which also used studies using QST, found that there was hyperalgesia to cold in 82% of the studies involved, BUT, there were no alterations in the detection of non-noxious cold stimulations. 

Currently, it is supposed that there is a subset of people with Fibromyalgia who seems to have real issues regulating their body temperature, as some studies showed obvious differences in temperature sensitivity and others showed little to none. It’s well known that a lot of individuals with Fibromyalgia end up wrongly diagnosed. Fibromyalgia is more so a culturally adopted label, a diagnosis of exclusion. One condition that many with fibromyalgia end up being diagnosed with, is hypermobility and Ehlers-Danlos syndrome. Two conditions in which autonomic dysfunction is incredibly prevalent. Could this be the subset of people that is referred to? Well, it’s definitely a possibility.

Do those with fibromyalgia have an intolerance to the cold?

Well, it just isn’t as simple as that. It’s probably better to think of it as a subset of people diagnosed with Fibromyalgia who are affected.