The forecast as a painkiller — in reverse

The belief that weather hurts has itself been measured as a factor in how much it hurts. That's not imagination. It's worse than that.

A study of fibromyalgia patients found a connection that's easy to predict: lower air pressure and higher humidity were significantly linked to higher pain intensity and greater discomfort. The interesting part isn't that connection. The interesting part is what turned out to explain how much any given patient reacted.

Among the patients, the belief that weather affects the pain was one of the main factors behind how weather-sensitive the pain actually measured to be. Not a footnote. One of the main explanations.

It's not what you think it means

It's tempting to read that finding as proof that the pain is imagined — that patients expect to hurt, and so they hurt "in their head". That's a wrong reading, and a dangerous one, because it hits people who are already fighting to be believed.

Expectation that amplifies pain is something different from imagining pain that isn't there. The study's own conclusion holds exactly that line: air pressure appears to affect fibromyalgia pain at the individual level and in interplay with emotional factors — not as a plain physical switch everyone reacts to the same way.

Stress as amplifier

The study found another connection pointing the same way. Of the weather variables studied, only air pressure was linked to the patients' stress levels. And stress level significantly moderated the effect: the higher the stress, the stronger the link between lower pressure and more pain.

Why it's hard to tell apart

That raises a methodological problem that isn't unique to this study. A review in Practical Neurology points out that the main limitation of relying on self-reported triggers is the reliability of the patient's own memory and selection — and that more patients believe weather is a trigger than the evidence supports. Layer that on top of the fibromyalgia finding, and the picture gets more complicated, not less. An expectation can colour what you remember about your pain. It also appears to be linked to how much the pain actually varies with pressure. The two things aren't the same, but they're hard to tell apart in practice.

It's the same underlying mechanism that makes people find connections in number sequences that are pure chance: in a classic experiment, 97 students were shown two uncorrelated number sequences and perceived a connection between them anyway. We're good at confirming what we expect. That's true of numbers on paper. It appears to be true of pain in a body too.

What you can do about it

You can't think your way out of an expectation effect by deciding not to have one. But you can measure how your pain actually tracks pressure over time, as a supplement to the feeling — not a verdict on it.