People with multiple sclerosis (MS) often experience a temporary worsening of their symptoms in hot weather or when they run a fever. These temporary changes can result from as little as one-quarter to one-half of a degree elevation in core body temperature, as an elevated temperature further impairs the ability of demyelinated nerves to conduct electrical impulses.
![How Heat Affects Multiple Sclerosis Symptoms](https://www.mssupportfoundation.org/wp-content/uploads/an-overview-of-heat-intolerance-and-ms-2440799_final-2a1e18c7a75a44f3884882d0523eca65.webp)