It can affect symptoms like vision problems, fatigue, pain, and weakness.
Uhthoff’s phenomenon can happen even after an elevation of body temperature as small as one-half of a degree.
This sensitivity to heat is quite common, affecting an estimated 60%-80% of MS patients.
Verywell / Cindy Chung
Uhthoff’s phenomenon is experienced as a worsening of neurological symptoms in response to an increase in body heat.
Myelin allows your nerves to communicate with each other effectively and quickly.
When it’s damaged, your nerve cells can’t properly transmit messages.
Keep in Mind
No permanent neurological damage is done by Uhthoff’s phenomenon.
Any MS symptoms that get worse with heat reverse once your body temperature goes back to normal.
These may potentially allow you to still enjoy some of your triggers without getting overheated.
One approach is to wear cooling garments like a cooling scarf, vest, or headwrap when you exercise.
Could It Be a Relapse?
With an MS relapse, the symptoms will persist.
Uhthoff’s phenomenon doesn’t cause any long-term damage and it doesn’t mean that your MS is worsening.
Davis SL, Jay O, Wilson TE.Thermoregulatory dysfunction in multiple sclerosis.Handb Clin Neurol.
2023;71(1):149-150. doi:10.4103/0028-3886.370435
Multiple Sclerosis Trust.Uhthoff’s phenomenon.
Multiple Sclerosis Foundation.Understanding and avoiding Uhthoffs phenomenon.
2016;9(1):101-105.
2019;27:419-423. doi:10.1016/j.msard.2018.11.013
Multiple Sclerosis Society.Hot and cold: the effects of temperature on MS.
