Heat Sensitivity With Multiple Sclerosis

August 3, 2026 /
MS Cognition

If you live with multiple sclerosis, you may notice that your symptoms feel worse when the weather is very hot or humid, or when you have a fever. And you are far from alone: 60-80% of people living with MS experience heat intolerance. Fortunately, symptoms usually only worsen temporarily. They should improve after you cool down.

Cause of MS Heat Intolerance

A higher body temperature makes it harder for nerves damaged by MS to conduct electrical signals. In fact, research shows that raising your body temperature even half a degree can affect how nerve signals work. This can make it harder for you to function.

What Does MS Heat Sensitivity Feel Like?

If you have MS heat intolerance, activities such as sunbathing, exercising and taking very hot showers or baths may make your MS symptoms worse. You may even have new symptoms. Because MS is unpredictable, heat sensitivity can vary from person to person. If your symptoms are mild, you may do better than someone with more severe ones.MS symptoms that get worse with heat and humidity include:

  • Blurred vision
  • Cognitive difficulties such as problems with attention and concentration
  • Fatigue or reduced energy
  • Muscle weakness
  • Numbness in the arms and legs
  • Slowed reaction times
  • Spasticity
  • Tremor

Tips for Keeping Cool

In hot and humid weather, these strategies can help you stay cool with MS:

  • Stay in the air conditioning during periods of extreme heat and humidity. With a prescription, the cost of an air conditioner may be tax deductible.
  • Wear lightweight, loose and breathable clothing.
  • Drink cold fluids and eat popsicles.
  • Exercise in a cool place or pool (under 85 degrees Fahrenheit) and at cooler times of day.
  • Try cooling down before and after exercising. This will decrease the exercise’s heating effects. To do this, get into a bathtub of lukewarm water and continue adding cooler water over a period of 20 to 30 minutes.

Cooling Equipment To Lessen the Effects of Heat

To help with the heat-related effects of MS, some companies have designed cooling garments and equipment. These can include misters, cooling vests, hats or caps, and wrist, ankle or neck wraps.To select the right products for your needs, consider:

  • What is the cooling garment made of?
  • What is its total cooling time?
  • How much does the garment weigh? Is it designed to fit under or over regular clothing?
  • What is the method of cooling? For example, does it require a source of electricity or does it rely on ice or gel packs?
  • Which method works best in your specific climate?
  • Will your health insurance cover it?

Covering the Cost of Cooling Equipment

Your health insurance may cover the cost of cooling equipment. Cooling equipment is usually considered durable medical equipment (DME). This means it is medical equipment that is meant to be used again over time. If cooling equipment helps you do your job — for instance, if you work outdoors — it may be covered through vocational rehabilitation. Call your insurance company and ask what steps you need to take to get the equipment approved.

If your plan denies your request, you can follow the steps for filing an appeal or asking for an exception. You can use this sample cooling equipment appeal letter.

An MS Navigator can help you find other resources if your insurance doesn’t cover cooling equipment. Companies that offer discount codes include:

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