MS and Heat Tolerance: How Heat Affects People with Multiple Sclerosis

Updated from original article published May 26, 2020

It has long been observed that most persons with Multiple Sclerosis (MS) are very sensitive to the effects of overheating. One hundred years ago, the way persons with MS were diagnosed was to put them in a bath containing hot water, the “hot bath test”. If they became weak or developed other neurologic symptoms, this was taken as evidence that they had MS.

How Does Heat Affect MS and Heat Tolerance?

The basic problem in Multiple Sclerosis is that nerves are damaged and are not able to conduct chemical and electrical signals in an efficient and coordinated manner. If a damaged nerve becomes heated, it causes further difficulty with electrical transmission. Importantly, the heat does not cause more or new damage to the nerve itself, but temporarily impedes its ability to function.

This is why many persons with MS may notice a temporary worsening of symptoms if they have a fever, or become overheated through exertion, or are in a heated environment. This is known as a “pseudoexacerbation”, i.e. an MS flare-up that is due to a known precipitant, in this case, heat. Generally, when the person cools down, the symptoms improve. This temporary worsening of function is a hallmark of temperature sensitivity in people with MS and is not a sign of new disease activity.

Tips To Stay Cool This Summer For Those With MS and Heat Tolerance Challenges

When going outside, wear a hat, stay hydrated, and use cooling strategies to manage MS and heat tolerance more effectively.

• There are cooling towels and bandanas that can be made to stay moist and cold, and which will rapidly cool someone down when placed on the head or neck to regulate body temperature.
• There are cooling vests with pockets into which cold packs can be placed, and worn if prolonged heat exposure or hot weather is a concern.  
• A small portable pocket fan may also help. These same strategies can be used when exercising to minimize heat intolerance and support better health during the summer.

Keeping Cool Inside to Support MS and Heat Tolerance

Inside, fans and air conditioning are helpful for regulating core temperature. For persons with medical conditions that require consistent indoor heating or cooling, there are allowances that can be obtained from the power company.

Exercising and Keeping Cool

Swimming is a great exercise because the water dissipates body heat. It is recommended that the pool not be heated to more than about 85 degrees to reduce heat-related symptoms and fatigue pain.

In general, persons with Multiple Sclerosis should avoid hot tubs and saunas, as they can elevate body temperature and worsen symptoms related to MS and heat tolerance.

For individuals with temperature sensitivity, choosing the right exercise environment is essential to avoid overheating.

Conclusion: Managing MS and Heat Tolerance Year-Round

MS and heat tolerance remain significant considerations for individuals living with Multiple Sclerosis, specially during hot weather and warmer months. Understanding your personal temperature sensitivity and using proven cooling methods can help prevent unnecessary symptom worsening and improve quality of life.

Questions?

For more information or to schedule an appointment, contact Pacific Neuroscience Institute’s MS specialists at 310-582-7613.

FAQs: Managing MS Symptoms in the Heat

Is heat intolerance a symptom of MS?

Yes, heat intolerance is common among individuals with Multiple Sclerosis. Increased body temperature can temporarily worsen MS symptoms, but it does not cause new nerve damage.

Is MS worse in the summer?

Many people experience more pronounced MS and heat tolerance challenges in the summer due to hot weather. Using cooling packs, wearing light clothing, and staying hydrated can help.

Are hot showers bad for MS?

Hot showers can temporarily worsen MS symptoms due to elevated core temperature. It’s often recommended to use cooler or lukewarm water to avoid heat intolerance.

Is hot weather bad for multiple sclerosis?

Hot weather can trigger temporary symptom flare-ups in people with MS, often referred to as pseudoexacerbations. Staying cool and using cooling vests or cold packs can help manage temperature sensitivity.

Is the sun good for persons with MS?

Moderate sun exposure may help with vitamin D production, which is important for overall health, but excessive heat or sun can worsen MS symptoms. It’s essential to balance sun exposure with strategies to stay cool