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How Temperature Affects Your MS

By Daryl H. Bryant (764 words)
Posted in Living with MS on August 6, 2015

There are (2) comments permalink

How Temperature Affects Your MS

If you’re suffering from Multiple Sclerosis, then you know that temperature changes – even the slightest ones – can have a huge effect on your symptoms. As we head into the hottest month of the summer and later into fall and winter, the warm and cold temperature changes may cause a few symptom outbreaks you were unprepared for. 

You may experience changes in your mood or appetite, loss of vision, or have trouble holding on to your train of thought. Whatever your symptoms, we offer a few tips for counteracting these hot and cold outbreaks. The more you know about how temperature affects your MS, the more you’ll be able to prepare yourself against symptom outbreaks.

Vision Loss

When it comes to temperature changes, vision loss is one of the most common symptoms. Many MS patients suffer from optic neuritis, or inflammation of the optic nerve, which means vision can get blurry or be temporarily lost during symptom outbreaks. 

In the heat especially, many MS patients experience blurry vision or complete loss of vision, but extreme cold temperatures can cause this outbreak as well. This is because the change in core body temperature causes the optic nerve to react, which doctor’s call the Uhthoff’s Phenomenon after the physician who discovered it. 

Remember, if you experience vision loss, it will only be temporary. 

What you can do about it: 
Once your body temperature returns to normal, your vision will be less blurry. If you are experiencing changes in your vision, stop whatever you are doing and immediately move to a more moderately temperate space until your vision returns. 

Cognitive Symptoms

A few years ago the Kessler Foundation produced a study monitoring the cognitive performance of MS patients during hot, summer days. Participants took a basic IQ test, and over 70% of the participants scored lower on the test during the hotter afternoons. 

This means that those of us suffering from cognitive symptoms and lapses have to take better care of ourselves during days of extreme heat. 

Cognitive symptoms often appear as lapses in train of thought, lapses in memory, inability to stay focused, and slow recall. 

What you can do about it:
If you feel these symptoms creeping up on you, try and move yourself to cooler area either back inside or to a cooler part of your home or office. Bring cold packs with you so that you can rest on your forehead or the back of your neck in order to bring down your body’s core temperature and reduce your cognitive symptoms.

Balance & Numbness

Muscle weakness is common among those with heat-sensitive symptoms. You may also notice a numbness in your limbs when your body temperature changes, or you may have shakes or tremors when it gets too hot or too cold outside. 

The heat in particular can take a toll on your muscle strength, which in turn can affect your balance, your spasticity, and your ability to walk. This is because increased body heat can make it difficult for messages to pass along the damaged nerves. Heat aggravates neurons, making it difficult for your brain to communicate with your limbs. 

What you can do about it:
If this is the case, find a comfortable place to sit and rest indoors or in a more temperate environment until your symptoms disappear and you can move comfortably again. 


Fatigue and exhaustion are common symptoms aggravated by temperature changes, and feeling too hot or too cold can drain your energy. Your body will go into overdrive in order to counteract the sudden symptom outbreak brought on by the temperature, resulting in your physical and mental exhaustion. 

What you can do about it: 
In order to avoid fatigue, avoid changes in temperature as best as you can. Many patients experience fatigue even during the slightest temperature changes, so it is important to carry cooling packs or warm clothes with you if you plan on being outdoors for a long period of time. 

What are you doing about temperature changes? 

Whatever your existing symptoms, changes in temperature can make them worse for a short time. Remember that these heat-insensitive or cold-intolerant symptom outbreaks are not true MS relapses, and they will disappear once your body returns to its normal temperature. 

The trick to reducing your MS symptoms is to recognize when your symptoms are getting worse and to counteract them right away by moving to a more comfortable environment until they disappear. 
Staying one step ahead of your symptoms is your best bet to living symptom free, and understanding how temperature affects your MS symptoms will give you the knowledge you need to stay on top of your MS.

Comments (2)

Jenn posted on: August 6, 2015

Humid heat really gets my ms, but when I go to the eastern side of WA state where it is a dry heat I feel awesome. I generally go to eastern wa. in the summer and camp, and the heat can be up to 100 degrees and it doesn't bother me and I feel happy,but here on the Western side it is generally a humid heat and it makes me bitchy, tired, cognition is yucky.

Daryl posted on: August 7, 2015

Jenn, I completely agree with you about the humidity. I live in NJ and it's humid half of the year. I do much better in the fall and winter months as the NJ summer heat and humidity is brutal sometimes. Although I work in an office environment every day, so the A/C definitely helps :)

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