Featuring Barry A. Hendin, MD 

MSAA’s Chief Medical Officer 

Question: What are the symptoms of heat sensitivity in MS, and how is it best treated?

Answer: Heat sensitivity, also known as Uhthoff’s Phenomenon, describes an increase in MS symptomatology caused by overheating. This could be due to external influences, when a person with multiple sclerosis is in an excessively hot environment. Alternatively, this can relate to an internal increase in body temperature due to exercise or infection with fever. Sometimes, of course, it’s a combination of the two when people are exercising in an overheated environment.

The symptom that develops is often specific to the individual; usually it will be an exaggeration of an old neurological problem, such as a change in vision, when there has been a history of optic neuritis, or a change in strength, when there has been prior weakness. Sometimes it is a generalized sense of fatigue or malaise. 

Fortunately, there are common-sense preventions and treatments for heat sensitivity. People with MS should be mindful of the temperature of their environment and consider doing their exercise or work in places or times of day that are cooler. Listen to your body regarding your tolerance for heat. Stay hydrated. Consider the use of cooling devices. If you need help in obtaining a cooling product, MSAA’s Cooling Distribution Program provides free cooling vests and accessories to individuals with MS who qualify for assistance. Additional strategies include resting, drinking a cold or frozen (non-alcoholic) drink, and taking a cool shower.

For more information, please visit MSAA’s webpage on heat sensitivity.

Barry A. Hendin, MD, is a neurologist and Director of the Arizona Integrated Neurology MS Center. He is also Director of the Multiple Sclerosis Clinic at Banner University Medical Center and Clinical Professor of Neurology at the University of Arizona Medical School.

MSAA’s Ask the Expert series received a Merit Award from the 26th Annual Digital Health Awards!