Heat or high humidity can make many people with multiple sclerosis (MS) experience a temporary worsening of their symptoms. Doctors believe that this occurs because heat causes nerves (whose myelin covering has been destroyed from MS) to conduct electrical signals even less efficiently. Most people with MS avoid hot baths, hot showers, and heated swimming pools.
For reasons that are not well understood, extremely cold temperatures and changes in temperature can also cause MS symptoms, usually spasticity, to flare.
Use air conditioning. If hot and humid conditions worsen your MS, try to stay in cool and dry areas as much as possible. A home air conditioner may be tax-deductible for some people with MS; talk to your doctor. Some people use a cooling vest on extremely warm days.
It is important to remember that while climate may worsen the symptoms of MS, climate changes do not produce more actual nerve damage. The adverse effects of temperature and humidity are generally temporary. However, it can take longer (a few days) to recover if you get overheated.