A figure showing a spine connecting to the brain with pain signals, and clouds of brain fog in the background.

What The Heck Is Brain Fog Anyway?

Brain fog sucks. It's considered a sort of cognitive dysfunction, marked by forgetfulness, hazy thinking, and inability to concentrate or focus.

Is it just being tired? Is it being so stressed about managing a chronic illness that you just sort of think less clearly? Is it a way of validating being lazy? And why do so many people have it?

Science has some theories:

A 2013 study exploring the mechanisms of chronic fatigue syndrome says brain fog is, "Not fully understood and often is described as slow thinking, difficulty focusing, confusion, lack of concentration, forgetfulness, or a haziness in thought processes."1

The study's authors suggest it could be due to "the interaction of physiological, cognitive, and perceptual factors."1 It suggests that perhaps patients "require increased cortical and subcortical brain activation to complete difficult mental tasks" or have cerebral blood flow issues.1

Another 2020 study referred to the study as "so-calledbrain fog," suggesting that researchers still aren't sure what it is or how to define it.2 And that's because it seems there's there are no confirmed understood causes. That's because it's not an actual medical condition, even if it feels very, very real. It's more of a byproduct of a bigger issue.

So what about brain fog in axial spondyloarthritis patients?

I know I'm not going crazy when I say I feel brain fog on bad flare-up days — and I certainly didn't leave my full-time job because my brain was operating at its highest, more impeccable level. (Hint: Debilitating brain fog was a big part of why I left my job; it was impairing even menial tasks).

This may be a good explanation, via AnkylosingSpondylitis.net: "While not an actual medical condition, brain fog is a symptom of chronic arthritis conditions like ankylosing spondylitis [or radiographic axial spondyloarthritis]. Without getting too technical, during an AS symptom flare, signals to and from pain receptors interfere with normal brain function. Meaning, these pain signals literally “fog” up your brain like television static."

Makes sense, right? But a lot of us have brain fog even when we're not in an active flare-up. Other theories have to do with sleep not being restorative enough.

I have other theories

I think it's tiring — on a soul or bone level — to constantly force our bodies to participate in a society that often ignores us. Like when I worked that job which was unforgiving on my body (but probably totally normal for anyone else, although don't get me started on the American workweek set-up humans have somehow decided is natural).

If you spend all your time trying to keep up, fighting through the pain, pushing past the inflammation — you're bound to feel expended. Humans aren't meant to meet all these demands: Digital lives, work lives, social lives domestic lives — all while trying to balance an illness.

Another idea? Trauma. I think there's a lot to be said about how trauma can affect us (and this can be the trauma of being sick, of course). If you grew up with trauma, it can wreak havoc on your stress levels, inundating your body with cortisol.3 This can tax the body, leading to a sense of exhaustion.

Psychology Today says traumatic events "create what neuroscientists are recently exploring in the brain, including cerebral atrophy and loss of gray matter. So becoming aware of PTSD symptoms can be helpful to a person struggling to understand how to seek treatment."3 To further clarify, when the grey matter in our brain atrophies it can lead to, "cognitive deficits and mood disorders," according to studies.4

Plenty of people write brain-fog off as laziness or sleepiness — but the science is there. It is real. 

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