Heat sensitivity in MS

Epub: Romberg et al. The effects of heat stress on physical functioning in persons with multiple sclerosis. J Neurol Sci. 2012 May 28.

Background: Heat sensitivity is a well-recognised feature in MS. However, little is known about how heat affects physical performance in MSers. 

Objective: To evaluate the effects of short-term heat stress on physical functioning in MSers. 

Methods: 23 heat-sensitive MSers and 19 healthy controls participated. Moderate heat exposure took place in a dry Finnish sauna. Measures of upper and lower extremity function, static and dynamic balance, and walking capacity were applied. Core body temperature was measured by a telemetric physiological monitoring system. Assessments were conducted before, immediately, 1hour, and 1day after the heat exposure. 

Results: MSers showed a significantly (P=0.002) higher core body temperature than the controls following the heat stress. Performances in walking (P<0.001), chair rise (P=0.005) and functional reach (P=0.04) were poorer in MS subjects than in controls immediately after the heat. No prolonged heat effects were observed. 

Conclusions: An increase in ambient temperature causes a higher core body temperature rise in MS subjects than in healthy controls. This rise in temperature is associated with acute, but not prolonged detrimental effects on physical functioning.

"It looks as if MSers have a problem with controlling their core, or inner body, temperature compared to control subjects. This is not surprising as the temperature control is part of the autonomic nervous system and resides in a part of the brain called the hypothalamus. We know from pathological studies that MS affects the hypothalamus and presumably this affects the area that controls body temperature."

"It is well know that MSers, particularly with advanced disease, are more susceptible to hypothermia. I have had several MSers under my care with this problem. Therefore is a another problem, on a long list of problems, for MSers to watch-out for."

"As MSers can't control their body temperatures as well as control subjects this has a major impact on the functioning of their nerves that are damaged or remyelinated as they become sensitive to temperature and block or stop conducting at even modest rises in core body temperature."

"How many of you have heat sensitivity and how do you cope? For example, one of the MSers I care for has a walk-in butcher's fridge built into her house. She sits in it for 30 minutes at at a time to cool off; her functioning, in particular her mobility, is so much better after cooling. Other buy an wear NASA cooling suits. The problem with all these 'cooling solutions' is that they have not been studied in a vigorous enough way and none of them are therefore licensed by the NHS for use. May be we should do something about this!"