Wednesday, May 6, 2009

Hot Temps and Jello Legs

Heat-Sensitivity and the Pseudoexacerbation

Many people with MS experience a temporary worsening of their symptoms when the weather is very hot or humid or they run a fever, sunbathe, get overheated from exercise, or take very hot showers or baths. For example, some people notice that their vision becomes blurred when they get overheated—a phenomenon known as Uhthoff's sign. These temporary changes can result from even a very slight elevation in core body temperature (one-quarter to one-half of a degree) because an elevated temperature further impairs the ability of a demyelinated nerve to conduct electrical impulses.

The ‘Hot Bath’ Test Used for Years to Diagnose MS

For many years, the “Hot Bath” test was used to diagnose MS. A person suspected of having MS was immersed in a hot tub of water, and the appearance of neurologic symptoms or their worsening was taken as evidence that the person had MS. So heat is a very effective method of bringing out or increasing the symptoms of multiple sclerosis.

Heat-Related Symptoms are Temporary

It is important to remember that heat generally produces only temporary worsening of symptoms and does not cause more disease activity (demyelination or damage to the nerves themselves). The symptoms are generally rapidly reversed when the source of increased temperature is removed. People with MS who are planning to move to a very warm climate should try to visit first; plans may have to be changed if the weather seriously worsens MS symptoms.

Read this post in its entirety:

Multiple Sclerosis Relapse or Pseudoexacerbation? Part Two


  1. Jello legs made me laugh...when I was trying to describe it to my doctor i called it cooked spaghetti legs LOL

    Heat is my worst enemy!

  2. Thank you for this article! I live in Texas and will be traveling to Florida so this was very helpful. I love your site and truly appreciate it!

  3. It is like clockwork, it gets hot and humid, my right eye starts to fade in and out. What's the opposite of jello legs, because I'm still waiting for those!

  4. Andy,
    The opposite of jello legs is frankenstein legs. Where they don't bend at all. Now I'm sure you have experienced that.