When your body gets overheated, 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.
Another possible reason is if you have a lesion (damage to nerves) in the part of your brain that controls temperature regulation, hot or cold weather can then be harder to manage.
For example, MS may interfere with the signals to your sweat glands that help you cool down in hot temperatures, causing you to feel overheated.
Likewise, cold or cool temperatures can also cause symptoms to worsen. While less common than heat sensitivity, cold weather can set off:
- 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.