Heat Intolerance (Vitally Important - Especially during Summer)

Heat intolerance, or anhidrosis as it is scientifically known, is a classic symptom of MS where a rise in temperature whether it’s internally or externally, may temporarily increase MS symptoms.

What causes in Heat Intolerance in MS?

The destruction of myelin, the protective sheath which surrounds and protects nerve fibres causes the formation of plaques on the nerves which slow nerve impulses. A build up of heat slows down nerve transmission causing symptoms to worsen.

Many people with MS experience a temporary worsening of their symptoms when the weather is very hot or humid or they’re running a fever, sunbathe, get overheated from exercise, or take very hot showers or baths.

These temporary changes can result from a very slight rise in core body temperature, even as little as one-quarter to one-half of a degree, because an elevated temperature further impairs the ability of a demyelinated nerve to conduct electrical impulses.

What are the symptoms of Heat Intolerance?

• Some people notice that their vision becomes blurred when they get overheated; this is known as Uhthoff's Symptom.
• Others report an increase in symptoms such as fatigue, general tremor, intention tremor, decrease in cognitive function and memory problems.

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 neurological symptoms or worsening of symptoms was taken as evidence that the person had MS (interesting, no?).

It must be emphasised heat coupled with increased humidity generally produces only temporary worsening of symptoms and does not cause more actual tissue damage. The symptoms are generally rapidly reversed when the source of increased is dealt with and it is most important to remember that heat does not cause an actual exacerbation.

How can Heat Intolerance be managed?

• By drinking lots of fluids, preferably water or diluted fruit juices because dehydration due to perspiring can make it worse.
• By sucking on ice cubes or ice lollipops can help.
• By trying to remain in air-conditioned surroundings as much as possible on hot and humid days.
• Some people find cooling down before activity, by having a cold bath or shower gives them more energy or stamina.
• Using cooling products such as a mister spray or cooling gel in wristbands or scarves is also extremely effective.

(Heat, 2012).

Reference

Multiple Sclerosis Resource Centre. (2012). Heat intolerance. Retrieved June 26, 2012, from http://www.msrc.co.uk/index.cfm/fuseaction/show/pageid/1708