I live in Florida, and during the holiday season, many of my patients return north for a few weeks. When they return to Florida, I get ready to hear the complaints of how the cold weather flared up their arthritis. Many practitioners believe that this is nonsense, and maybe it’s just stiffness from the car or plane ride. Maybe. I have a theory though that would lend credit to the cold weather complaints, and it has nothing to do with my training as a physio. It’s from scuba diving. 

I was an avid diver for many years, and I spent some time working on a boat in the Philippines. With scuba, you have to understand pressure to avoid the bends, which is a rapid release of nitrogen in the body and can cause death. So if you’ve ever heard that you should ascend only as fast as the slowest bubbles, this is a rule of thumb to avoid getting the bends. 

Perhaps you remember from high school physics that pressure and volume vary inversely. In scuba, this means that the deeper you go, the more the air in the tank gets compressed. So you literally have less time at lower depths (another reason that I prefer shallow dives). The converse is true, as you rise, the air expands and this is the dangerous part of scuba. You have to rise at a rate that allows the expanding air to escape your body. If you’ve blown bubbles from the bottom of a deep pool and notice the bubbles get larger as they rise, you’re witnessing the rule of physics. 

So what does this have to do with arthritis? Inside your joints, you have fluids and gas bubbles. When it is hot outside, it is a high pressure system and compresses the gas bubbles. During times of inclement weather, the atmospheric pressure is lower. This means that the gas bubbles are allowed to expand, increasing pressure inside the joint. Joints don’t have extra space, so even the most minute increase in pressure can cause pain. So when people tell me they have a barometer in their knee, I believe them.