A rise in temperature does not affect everyone with multiple sclerosis (MS), but for many people with MS at least some of their symptoms get worse when they get hotter. This temperature effect is sometimes described as Uhthoff’s phenomenon, after Dr. Wilhelm Uhthoff, who first described it in 1890. The worsening of symptoms due to heat is widely recognized and very common. Studies have shown that nerves with damaged myelin are sensitive to changes in temperatures. Researchers note that a rise in temperature may cause a failure in the effective transmission of signals from the brain to the body (nerve conduction), and a reduction in temperature may allow more signals to be transmitted across the damaged nerve.
Symptoms may include: blurred vision after exercise, fatigue, dizziness or a weakness in one or both legs. Prolonged exposure to heat might make fatigue worse, which might in turn make other symptoms feel worse. Although this temporary worsening of symptoms (known as pseudo-exacerbation) may feel like a real MS attack, the symptoms will usually improve as the bodies temperature returns to normal.
Heat or exercise related symptoms may be brought on by activity, sunbathing, hot baths, emotion, exercise, fever or other things associated with an increase in body temperature. Many people with MS find hot weather difficult, but even in cooler weather, hot showers, or even daily activities like cooking in the kitchen or using a hair dryer can sometimes be a problem.
Unfortunately, many of these may be insufficient, uncomfortable or impractical while living a full, active life. The answer may be found in the many varieties of body cooling garments made especially for people with MS. These garments include cooling vests, wrist bands, neck and upper spine collars, hats and many other items. The beneficial effects of cooling garments have been noted in several clinical studies, and their use is usually well tolerated. They can be used either as preventative measures or ways to recover from overheating.
Note: Before using any cooling garment or device you should talk to your health care professional.
Cooling and Multiple Sclerosis MSAA
Multiple Sclerosis Cooling Foundation
Multiple Sclerosis Society – UK
"Living with MS, newly diagnosed” NMSS