Temperature sensitivity

The brain helps regulate body temperature in hot and cold environments. Multiple sclerosis (MS) can make it harder for the body to maintain this balance, leading to heat and cold sensitivity. Learn how MS heat sensitivity and cold intolerance affect symptoms and how to manage them.

MS and heat sensitivity

The central nervous system controls how the body responds to temperature changes. Because MS damages nerve pathways, messages between the brain and body can slow down when you get too warm. This can temporarily worsen symptoms, a reaction known as Uhthoff’s phenomenon (or Uhthoff’s syndrome or Uhthoff’s sign).

If you live with MS in heat, you might notice blurred vision, fatigue or muscle weakness on hot days. These effects usually ease once your body cools down.

By planning ahead and using cooling strategies, you can reduce the impact of heat with MS.

Why MS affects heat and cold tolerance

When the body overheats, it can slow down the messages between the nerves in the brain and other parts of the body. Since MS already damages these connections, it can trigger MS symptoms.

Lesions (damage to nerves) in the part of the brain that regulates temperature can also make it hard to adjust to hot or cold weather.

For example, MS and heat sensitivity can interfere with the signals to sweat glands that normally help to cool the body. As a result, you may feel overheated or fatigued.

Cold temperatures can also cause problems, although this is less common. Cold weather may lead to:

• Nerve pain and sensory symptoms such as tingling or numbness
• Difficulty moving caused by muscle stiffness (spasticity) or spasms
• Fatigue and depression, although this may be due to the lack of sunlight or other factors, rather than exposure to the cold

Ways to stay cool on hot days

• Stay hydrated with water or cold fluids (limit caffeine).
• Wear lightweight, loose-fitting clothing and a hat.
• Avoid direct sun and stay in shaded or air-conditioned spaces.
• Use a spray bottle or cooling towel on your face and wrists.
• Keep your home cool with fans or air conditioning.

Ways to stay warm on cold days

• Keep moving to boost circulation and reduce stiffness.
• Layer clothing to maintain a comfortable temperature.
• Enjoy warm food and drinks (avoid alcohol, which can lower body temperature later).
• Close doors and curtains to retain heat.
• Use hot water bottles, electric blankets and heat pads, but take care if MS has altered your skin sensitivity to heat.

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