It's A Heat Wave!..

Break out the fans and blend me a Margarita! It’s supposed to hit record highs here in the Pacific Northwest/Seattle Metropolitan area and it is ONLY May! And “The Bush” says there’s no proof of global warming…

Living in an area of the USA where no one has air-conditioning in there home because it isn’t needed, can pose a difficult task in staying cool when temperatures soar. Summers in the Pac Northwest are generally mild, ranging in temperatures from the mid 60’s to 80’s. It’s just usually not HOT here, except for a few weeks in July and August. And hunkering down in a movie theater in the summer is the best place I have found to suck up semi-free air-conditioning and entertainment at the same time!

When my personal body temperature rises, I find several of my underlying MS symptoms become more predominant. For instance, my fatigue increases, I tend to get a blurring of my vision, and I have muscle weakness in my left arm and leg. These symptoms will usually decrease or go away completely if I can cool off and relax a bit.

The technical term for a worsening of MS symptoms causes by increased body temperature is “Pseudo Symptoms” because the symptoms mimic those one might begin to see in a real relapse. The difference is once the body temperature is lowered, the symptoms will spontaneously remit/go away, whereas in a true relapse, the symptoms will stay even if the body temperature is decreased.

So for those of you just learning about the wonders of Multiple Sclerosis, you may be asking, “Why does heat/increased body temperature affect MS symptoms?” This a good question and there are only theories why this happens. I’ve done a bit of research into the matter and will share some of what I found with you now:


Heat adversely affects nerve transmission and makes MS symptoms worse. Here's why. Signal transmission in the nervous system is helped, up to a point, with an increase in temperature, approximately up to our normal 98.6 degrees (degrees Centigrade). Push your temperature any higher than normal and nerve transmission slows. That is one reason why you feel fatigued in the heat or with a fever. It has been found that in axons that lack myelin as in MS, this temperature transmission curve is pushed to the right a bit, that is, conduction velocity is optimal actually a little shy of 98.6 or 37 degrees Centigrade and at above normal temperatures, conduction drops off even more precipitously.

So what does that mean? In simple terms, it means if you heat up the insulation around your nerves, the signals won’t go as fast as they usually do to the places they usually go to make things happen or the signal gets interrupted altogether. And if your nerves are running slower, YOU are going to run slower because the nervous system is the part responsible for conducting the current from your main fuse box to your light switches and so on.

Weather and the seasons can adversely affect daily living in many people with multiple sclerosis also. The greatest number of relapses or flare-ups occurs in the coldest months (January and February) as well as in the warmest months (July and August). This is because both the extreme cold of winter and the extreme heat and humidity of summer can worsen existing symptoms as well as produce new symptoms of MS.


Sometimes a temperature change may produce a temporary improvement in one symptom and, at the same time, a temporary worsening in another symptom. For example, in one person with MS, a hot bath resulted in the improvement of numbness and walking, but caused a temporary blurring of vision in the left eye. This is called a "dual response" to temperature. In another kind of "dual response", heat and cold may produce worsening of existing symptoms as well as the development of new symptoms.

There have been several studies over the past few years and decade that have looked into the effects of temperature changes and cooling in people dealing with Multiple Sclerosis. Here is a list of several research studies and summary quotes:

Effect of Cooling on Physical Performance in Multiple Sclerosis
Dr. George Kraft, principal investigator, and Alan Alquist, research scientist, University of Washington MS Clinical & Research Center, Seattle, Washington (completed in 1996). Summary Quote:

“Subjectively and objectively, we noticed remarkable gains [for those with] heat-sensitive MS [in their] ability to perform repetitive activities. We believe this may be an important finding for MS patients for it is repetitive motor tasks that elicit extreme local and central fatigue in MS patients.”

Enhancement of Cognitive Processing by Multiple Sclerosis Patients Using Liquid Cooling Technology: A Case Study
L.D. Montgomery, R.W. Montgomery, Y.E. Ku, Lockheed Martin Engineering & Sciences Company; and NASA Ames Research Center, Moffett Field, California (completed in 1997).Summary Quote:

“This case study indicates that ‘cooling therapy’ may be used to temporarily improve the cognitive processing of MS patients.”

Temporary Improvement of Motor Function in Patients with Multiple Sclerosis after Treatment with a Cooling Suit
Jergen Kinnman, MD, PhD; Ulf Anderson, MD, PhD; Ylva Kinnman, MD; and Lil Wetterqvist; Department of Neurology, Länssjukhuset, Halmstead, Sweden, Journal Neuro Rehab, 1997, 11, pp. 109-114.Summary Quote:

“After cooling, ten out of fourteen ambulatory patients and all six wheelchair patients were improved in at least one motor test.”

Cooling Garment Treatment in MS: Clinical Improvement and Decrease in Leukocyte Nitric Oxide (NO) Production
E.A.C. Beenakker, MD; T.I. Oparina, PhD; A. Hartgring, MS; A. Teelken, PhD; A.V. Arutjunyan, PhD; Dsci; and J. De Keyser, MD, PhD; Academisch Ziekenhuis Groningen, The Netherlands, Neurology, 2001, 157, pp. 892-894.Summary Quote:

“Active cooling was associated with a decrease in mean leukocyte nitric oxide (NO) concentration by 41%... NO is a diffusible gas that can enter the CNS and block conduction in demyelinated axons through a mechanism that is not completely understood... Although several other mechanisms may be responsible for the beneficial effect of cooling in MS, results raise the intriguing possibility that a lowering of leukocyte NO production may play an important role.”
This study was supported by a grant from MSAA’s affiliated organization, Multiple Sclerose Internationaal, Amsterdam, The Netherlands.

A Randomized Controlled Study of the Acute and Chronic Effects of Cooling Therapy for MS
S.R. Schwid, MD; M.D. Petrie, RN (University of Rochester, Rochester, New York); R. Murray, MD, Jennifer Leitch, RN (Rocky Mountain MS Center, Englewood, Colorado); J. Bowen, MD, A. Alquist, PhD (University of Washington, Seattle, Washington); R.G. Pellegrino, MD, PhD, Maria Dawn Milan, RN (Institute for Neurology and Neuroscience Research, Hot Springs, Arkansas); Adam Roberts, Judith Harper-Bennie (Multiple Sclerosis Association of America); R. Guisado, MD (Center for Neurodiagnostic Research, San Jose, California); B. Luna, MS, Leslie Montgomery, PhD, Richard Lamparter, MS, Yu-Tsuan Ku, MS, Hank Lee, BS, Danielle Goldwater, MD (NASA Ames Research Center, Moffett Field, California); G. Cutter, PhD (AMC Cancer Research Center, Denver, Colorado, independent biostatistician); Bruce Webbon, PhD (NASA program manager and principal investigator), Neurology, 2003, 60, pp. 1955-1960.Summary Quote:

“Although other studies have demonstrated that continuous cooling can promote improvement in neurologic signs over several days, no other study has systematically assessed the long-term benefits of daily cooling, as patients would typically use it. We found no evidence that cooling effects changed over time. Given the lack of side effects observed in this study, modest improvements demonstrated using objective measures of motor and visual function, and persistent subjective benefits, cooling therapy could be considered as a potential adjunct to other symptomatic and disease-modifying treatments for patients with MS.”

So, as I watch the mercury rise on the thermometer outside today (rather a joke because mercury isn’t USED anymore in thermometers due to it’s toxicity), I’m going to sip some icy beverage and perhaps frighten my neighbors with my pasty, white legs in shorts. It’s not about fashion, people…it’s about STAYING COOL!