When I was younger, my grandma would occasionally issue solemn prophesies for rain. These declarations would come after she’d spent a few minutes rubbing her arthritic wrists. With a pensive gaze, she’d credit the prediction to her aching joints.
I was reminded of this yesterday. I’d been working on my laptop when my ankle, titanium-braced from an old break, started throbbing. I thought nothing of it until I stepped outside, and into a surprise rainstorm. I’d always been skeptical of grandma’s arthritic omens, but limping down the sidewalk in the wake of my own revelation gave me reason to reconsider. Could science have an answer for why some people seem to feel the weather in their bones?
Turns out, scientists have been studying this for several decades. The answer has been tricky to nail down, but most of the research seems to indicate that bones and joints, weakened by age or injury, seem to be sensitive to subtle changes in barometric pressure. This is a measurement of the atmosphere’s density, and sudden changes (especially drops) typically signal a change in the weather.
In one of the earliest studies (paywall) to establish this link, published in 1990, a pair of scientists from the University of Pennsylvania put four arthritic patients in a chamber where they had control of the temperature, humidity, and barometric pressure. Three of the patients reported an increase in pain whenever the pressure dropped. This was too small a group to draw hard conclusions, but more studies in the following decades have supported the findings.
Rather than shove patients into artificial atmospheric bubbles, most of the later studies compared patients’ reports of their pain with data from weather stations. One of the most recent, published in 2007, matched up the reports of 200 arthritis sufferers from across the country with temperature, humidity, and pressure data from local stations (almost all of the weather stations were within a mile of a subject). They too found that joint pain often preceded a change in barometric pressure.
As the researchers point out, figuring out exactly what is happening inside a joint as barometric pressure rises or falls would require some fairly invasive procedures. So the definitive study hasn’t yet been done. Researchers have, however, used findings from physiological studies in people to come up with a hypothesis.
The air pressure, they believe, is messing with the fluid that keeps your joints lubricated. Not only does this fluid let your joints hinge, twist, and swivel, it helps stabilizes them so you can keep your balance. Your body’s squishy parts are susceptible to atmospheric pressure. They swell when the pressure drops. This is why your feet swell during air travel, and the fluid in your joints is probably no exception. In 1990, a group of researchers did tests on cadavers’ hips and found that the joint’s fluid pressure seemed to be regulated by the outside air pressure. From this, researchers in the 2007 paper speculated that as these fluids respond to barometric changes, they would irritate the inflamed, arthritic joints.
Of course, this hypothesis isn’t airtight. The body is a complicated system that is constantly surprising scientists. Besides, there are plenty of people with arthritis whose aching joints have no auspicious abilities. And it doesn’t help me understand whether my healed fracture—which is neither a joint nor arthritic—has become a bellwether.
But, it’s good to know that science is looking into this. In the event of a major storm, I think I could do pretty well for myself as an ersatz meteorologist. In the meantime, I’ll keep working on my pensive, thousand-yard stare.
Source: wired.com
