May 14, 2010

Weather and Joint Pain

This is a common medical myth so deeply ingrained that it is rarely disputed. People everywhere are falling victim to conformation bias and reporting approaching storms based on the stiffness of their joints. Even though "atmospheric conditions, including temperature, pressure, and humidity, do not affect the temperature, pressure, or humidity inside the human body. Thus, there is no plausible way that the weather could impact joint pain" according to Brian Dunning.

Riding in an elevator provides a much greater shift in barometric pressure than common weather fronts, according to USA Today's article "Understanding Air Pressure." A simple ride in an airplane (including pressurized cabins) would cause an even greater affect than an elevator in a fraction of the time. If pressure did effect your joints it would cause a great deal of discomfort. Frequent fliers would be reporting the effect of air travel on their joints all the time, but they don't. In fact a quick search of PubMed for "air travel AND joint pain" reveals no published studies, probably because no correlation has ever been identified.

Changes in humidity are even less plausible. The human body has very specific hydration levels. The synovial fluid inside your joints is the same no matter what the outside conditions are. Walking through a sprinkler or jumping in a pool are examples of a dramatic change in humidity outside the body in a fraction of a second. These changes are much greater than changes in atmospheric humidity levels. Although water aerobics are beneficial for joint pain, it has nothing to do with the humidity around the body and more to do with the decreased joint stress in a buoyant environment. Changes outside the body do not affect the humidity of our joints.

Unlike weather conditions, using ice or heat packs can affect your deep tissue temperatures. This is why athletes or people with injuries find relief when using them. Weather, on the other hand, only affects the temperature of your skin. If weather is affecting your deep tissue temperature you are most likely experiencing hypothermia or heat stroke and your joint pains are the least of your problems.

Don't feel ashamed if you have fallen victim to this misconception. You may have experienced it yourself and were 100% positive it was caused by the weather. You have fallen victim to conformation bias and you are not alone. Dr. Javad Parvizi has collected anecdotal evidence from his patients and come to the same conclusion in his article "People with Joint Pain Can Really Forecast Thunderstorms." Not only has he used anecdotes to draw a conclusion, (a scientific method No-No!) he has personally noticed an increase in patients reporting pain during the summer which "brings many thunderstorms". However summer also draws people out of their homes into more active activities. This results in more joint injuries and arthritis. I'll bet he never thought of that! This conformation bias is the same logical fallacy ER Doctors commit when they report more incidents during a full moon, even when the data shows no such phenomenon.

Joint pain is not affected by weather. Weather is always changing and joint pain is too. However joint pain doesn't predict the weather and weather cannot predict joint pain.

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Anonymous said...

Your are SO wrong

Anonymous said...

How did you throw away the new year?