Air pressure and joint pain
Recent surveys suggest that 70 percent of Americans believe that weather influences their well-being. This is particularly true for the elderly, people who are chronically ill, and women and children.
People with joint problems such as arthritis often say that they are better predictors of bad weather than the most experienced TV forecaster. In fact, 93% of arthritis sufferers believing that weather affects their pain level.
A lot of research has gone into trying to figure out exact scientific mechanisms that bring about this kind of weather-related pain. Currently, however, none of the studies have produced any definitive explanation, though one factor these studies have in common is the link of pain to changing air (barometric) pressure. Some clinicians point to the fact that the nerve endings on the joints have receptors that can sense pressure changes. Heat and cold may also affect how people feel. A 2003 Japanese study published in the International Journal of Biometeorology found that there was a direct connection between low pressure, low temperatures and joint pain in rats. In the first documented animal behavioral study of weather effects on joint pain, scientists artificially produced chronic inflammation of the rat's foot, which was analogous to clinical features of human neuropathic pain. When the rats were placed in a low-pressure, low-temperature environment, they exhibited signs of foot joint pain that were not seen in control rats. A contributor to the Japanese study, Dr. Jun Sato, says that additional research has helped scientists zone in on where the rat is sensing the pressure change that causes pain. "It is highly possible that the barometric sensor and/or sensing system are located in the inner ear of rats," he said.
This will not seem unusual for anyone who's sat in an ascending or descending airplane. It remains to be seen if there is a similar sensing activity occurring in people with joint pain before a storm sets in. In addition to those afflicted with chronic joint pain from rheumatoid arthritis, many people suffering from nerve entrapment, having a limb amputated, osteoarthritis and lower back pain are also sensitive to weather changes. This same group of Japanese scientists have also linked decreasing ambient temperatures with more pain in their rat model. If a human connection is made, this might explain the condition that some sufferers feel with cold weather, called cold allodynia. This is a pain that is stimulated by something that is normally not painful (such as the wind) or that occurs somewhere other than where the pain was initially stimulated. Decompression sickness is a dangerous and occasionally lethal condition caused by nitrogen bubbles that form in the blood and other tissues of scuba divers who surface too quickly. Because the nitrogen bubbles that cause DCS can affect any of the body's tissues, including the blood, bones, nerves, and muscles, many kinds of symptoms are possible. Symptoms can appear minutes after a diver surfaces, and in about 80% of cases do so within eight hours. Pain is often the only symptom; this is sometimes called the bends, although many people incorrectly use that term as a synonym for DCS itself. The pain, which ranges from mild to severe, is usually limited to the joints, but can be felt anywhere. DCS is treated by giving the patient oxygen and placing him or her in a hyperbaric chamber, an enclosure in which the air pressure is first gradually increased and then gradually decreased. This shrinks the bubbles and allows the nitrogen to safely diffuse out of the tissues. Hyperbaric chamber facilities exist throughout the United States. No matter how mild one's symptoms may appear, immediate transportation to a facility is essential. Treatment is necessary even if the symptoms clear up before the facility is reached, because bubbles may still be in the bloodstream and pose a threat.
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