White Paper: The Effects of Cooling on Multiple Sclerosis
By Christopher J. Skok, Indiana University Bloomington
Written July 11, 2012, Updated June 16, 2014
An analysis of the benefits and advantages of utilizing cooling as a treatment for multiple sclerosis patients. Study was completed as a part of an internship for the Colllings Foundation of Stow, Massachusetts. Cooling has been seen as an alternative therapy in the current world of multiple sclerosis. Uhthoff’s phenomenon, the worsening of symptoms due to increases in temperature, has been seen to have an effect on MS patients and their quality of life. This paper proposes through primary as well as secondary research that cooling has a beneficial impact on MS suffers’ lives.
What is multiple sclerosis (MS)?
Multiple sclerosis is thought to be an autoimmune disease in which the body’s immune system destroys the protective sheaths otherwise known as myelin of nerve cells. The primary culprits, lymphocytes, types of white blood cells which help with acquired immunity, play a dynamic role in the disease. Two specific lymphocytes, T and B cells, play a defining role in the progression of MS .
v T cells, an immune cell originating in the bone marrow and maturing in the thymus, normally functions as an identifier in the human immune response. As foreign substances enter the body, T cells direct and activate other cells (i.e. B cells) to initiate the immune response against these substances.
v B cells, made and matured in bone marrow, assist in the manufacturing of antibodies to fight the foreign substances that have entered the body.
Both T and B cells contribute to the progression of MS. These lymphocytes operate by identifying foreign substances by antigens or small proteins that are present on the surface of these molecules. It is thought that these cells infiltrate the central nervous system, most notably the white matter of the brain, and severely malfunction. The malfunction results in the lymphocytes recognizing the myelin sheaths of nerve cells as a foreign substance by not recognizing the antigens on their surfaces. The myelin sheath, not unlike the insulation on a power cord, helps insulate the nerve cell and increase the speed at which signals are transmitted. The destruction of the myelin or demyelination of nerve cells by the lymphocytes causes certain symptoms that can be especially debilitating depending on the type and progression of the disease .
What are the different types of multiple sclerosis?
Relapsing-remitting: affects nearly 85% of individuals suffering from MS. Relapsing remitting consists of acute attacks or episodes with a full or almost full recovery following the episode.
Secondary progressive: often begins as relapsing-remitting. The main facet of secondary progressive is a gradual worsening of symptoms accompanied by fewer and fewer attacks.
Primary progressive: affecting about 10% of patients, PPMS progresses with no attacks and a steady increase in disability.
Progressive-relapsing: PRMS affects approximately 5% of patients and typically follows a pattern of acute relapses with or without full recovery .
Figure 1: Graphic representation of the different types of multiple sclerosis.
What are the symptoms of multiple sclerosis?
MS is typically defined by a patient going through a specific set of symptoms that go into remission and episodes known as relapses. Typical symptoms during these relapses include the following: numbness in limbs, partial or complete loss of vision, a tremor and lack of coordination, spasticity or the inability to easily move limbs, dizziness, and fatigue .
What are the effects of temperature on MS patients?
As detailed in a study published by the Journal of Neurological Sciences, a majority of patients suffer from the effects of heat. Over 80% of MS patients develop a panoply of neurological signs during hyperthermia, 60% of which are "new" to that patient,” .
This phenomenon is known as Uhthoff’s phenomenon. The phenomenon explains that as the internal temperature of MS patients rises, the symptoms of MS become significantly worse. The commonly accepted reasons behind this phenomenon include that as the temperature of the individual increases, the conduction of action potentials or signals in the brain becomes more difficult . As the transmission of action potentials becomes more difficult, the symptoms of MS temporarily worsen. The study below shows that the majority of conditions that provoke this symptom revolve around increases in body temperature, most notably physical exertion.
Factors provoking Uhthoff's symptom [Scholl et al, 1991]
No. of Patients
Per cent %
Hot bath or shower
Stress, anxiety, anger
Tired, end of day
Hot food or drink
Figure 2:Table detailing the effect of different activities on the provocation of Uhthoff’s symptom .
What are the effects of cooling on MS?
Over ten studies have concluded that cooling has a beneficial impact on MS patients. Ranging from many years and different studies, the experimental results suggest that cooling helps alleviate the symptoms of MS induced by an increase in heat.
v This study was completed by neurologist Jacques De Keyser, MD, PhD, of the University Hospital in Groningen, Netherlands and was published in Neurology, the scientific journal of the American Academy of Neurology. “Wearing a cooling vest can help multiple sclerosis (MS) patients with muscle strength, fatigue and balance. Muscle strength improved by an average of 10 percent. The level of fatigue also improved significantly,” .
v A study published in the June 2003 edition of Neurology yielded similar results. “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,” .
v At Stanford University, a study was conducted concerning the same subject. “The ability to effectively remove heat from the body could substantially improve the daily lives of heat-sensitive individuals with MS,” .
v A study published by the New England Journal of Medicine further supports the idea that cooling aids MS symptoms. “Detailed study of the effect under controlled conditions showed that symptoms and signs of multiple sclerosis may indeed improve after exposure to cold,” .
v Completed by researchers at Università di Genova in Italy, this study suggests cooling benefits both short and long term (i.e., acute and chronic respectively). “A clinical improvement was observed after both acute and, more unexpectedly, chronic cooling, whereas a significant improvement in central somatosensory conduction was recorded only under acute conditions,” .
v Researchers in Sweden have concluded similar findings regarding cooling and MS. “…selected activities of daily living performed in the patient's homes were evaluated and registered according to Assessment of Motor and Process Skills (AMPS). Six out of eight patients improved in at least one motor test and all patients improved according to AMPS,” .
v The Kessler Foundation in West Orange, New Jersey, concluded in a 2011 study the following: “…patients with MS performed 70 percent better on tests involving thinking, or cognitive functioning, on cooler days than they did at warmer times of the year,” .
v Researchers at Southern Methodist University in 2010 suggested that cooling can also have an impact on MS patients. “…some evidence exists concerning treatments (cooling, precooling, and pharmacological) for the MS patient to preserve function and decrease symptom worsening during heat stress,” .
v Research completed in Switzerland confirms that cooling aids MS patients. “The results using a tight-cuff cooling-garment prototype for peripheral cooling suggest improvement of a timed-walking test, leg-strength, fine-motor skills and subjective benefits.” .
v At University Hospital, in Orebro, Sweden (2006), researchers found similar conclusions about the benefits of cooling. “ (cooling promotes) statistically significant subjective improvement was also found in fatigue, spasticity, weakness, balance, gait, transfers, ability to think clearly and time to recover. The coherence between the objective and subjective results indicates clinical relevance from the subjects' perspective,” .
Can precooling before exercise also have an effect?
Two studies completed by researchers at the University of Utah and Stanford concluded that even cooling before exercise can be beneficial.
v A study conducted in 2005 in Belgium found that cooling reduces tremors in MS patients. “Both cooling interventions reduced overall tremor amplitude and frequency proportional to cooling intensity. Tremor reduction persisted during the 30 minute post cooling evaluation period,” .
v The effects of Uhthoff’s phenomenon can be avoided through the act of cooling the body. In one study, it was shown that “precooling was effective in preventing gains in core temperature with physical work and may allow heat-sensitive individuals with MS to exercise with greater physical comfort .
v The previously mentioned study at Stanford University also supports the importance of precooling: “Applying cooling to the general body surface takes advantage of the thermal inertia of poorly perfused superficial and peripheral tissues, however, to store a cold load. This cold load in the periphery then passively absorbs heat conducted into it by the blood flow and is the reason that precooling can improve endurance,” 
What is the difference between passive and active cooling?
Passive cooling refers to a process in which heat is being released without the aid of a mechanical device. Contrastingly, active cooling refers to cooling that takes place with the aid of a mechanical device (i.e. a pump) . A typical passive cooling equipment is a clothing garment that is highly mobile and of low weight. However, active cooling garments typically require one to carry around pumps or remain stationary so that fluid can be passed through an external device.
What are the choices for a passive cooling vest?
There are currently three different technologies being utilized for passive cooling vests.
v The oldest technology being utilized is evaporation which essentially acts as a large, moist sweat vest. This approach is inexpensive, however, it tends to be very uncomfortable and ineffective in humid environments.
v The second technology is low temperature phase change materials. The most common material used is ice (at 32°F) and gel packs (at 55-65°F). The primary problem with cooling to temperatures this low has to do with your body’s management of its heat known as thermoregulation.
Thermoregulation, a component of homeostasis, helps maintain optimal temperatures in your body. When the skin is lowered to this low of a temperature, a process called vasoconstriction or the constriction of the superficial blood vessels occurs . Normal skin temperature is typically around 90°F, so vasoconstriction inevitably occurs when you cool your skin to this level . .As this happens, less heat is being brought to the skin and thereby less heat can be given off by the body. Thus, while at first this may feel beneficial to the user, it can actually become counterproductive and even potentially dangerous.
A new third technology is now available, where phase change materials are “tuned” to an optimum cooling temperature of 82°F. By having a smaller difference in temperature when compared to skin temperature (i.e. 90°F vs. 82°F), vasoconstriction will not occur and blood flow will continue normally. This allows the transfer of heat from the skin cooling not only superficial blood vessels, but also the core temperature.
Who currently sells cooling vests?
As of June 2012, there are twenty-nine different companies that are now marketing cooling vests in the U.S. Each company features unique vests that utilize the three different technologies.
v There are currently nine companies that are marketing the first generation evaporation cooling technology.
v With regard to the second generation low temperature phase change materials, there are currently nineteen companies.
v There is currently only one company that offer the third generation optimum temperature phase change vests.
How do I maintain a cooling vest?
Active cooling systems require electricity and maintenance of pumps for efficient operation of the system. However, unlike second generation of passive cooling technology, it does not require refrigeration and can cool for long periods of time.
Second generation low temperature passive systems (55°F-65°F) require the cooling elements or the entire vest to be regenerated via refrigeration. This can take several hours to complete and the elements must be stored in a refrigerator.
Third generation passive systems which feature “tuned” phase change technology that uses cooling elements operating at 82°F stay “frozen” at temperatures below 82°F (i.e. room temperature) and require no special refrigeration. In order to recharge the vest, one may leave the vest at room temperature for two to four hours or put the vest in ice water and it will be fully recharged in 5 minutes.
The length of time a cooling vest cools for depends upon the technology used in the vest. Most cooling vests will last approximately 3-4 hours with some reaching 6 to 7 hours in duration.
How long does the cooling typically last?
The length of time a cooling vest cools for depends upon the technology used in the vest. Most cooling vests will last approximately 3-4 hours with some reaching 6 to 7 hours in duration.
Cooling has proven itself to be a promising treatment for patients diagnosed with multiple sclerosis. For all four types of MS, cooling in its different forms has been shown through numerous comprehensive studies to be beneficial. Whether passive or active, the cooling technology demonstrates a substantial positive effect on MS patients. Furthermore, pre-cooling prior to and during exercise holds benefits for most patients. Of the technologies surveyed, third generation phase change products that operate at approximately 82°F hold the most promise and most beneficial treatment. By cooling the skin temperature by only 8°F, the effects of thermoregulation and vasoconstriction can both be avoided with effective and safe cooling occurring. Also, the third generation passive technology vests are light weight and provide higher energy, less fatigue, and more freedom.
Recommendations for Future Research
Further study could be completed to confirm more precise details about cooling. Study should be conducted to determine the amount of precooling that yields the most benefits for patients. This figure could allow the most activity for MS patients and greater alleviation of symptoms. Study should also be conducted to determine under what environmental conditions that the cooling technology best operates. With the perfection of cooling technology, multiple sclerosis patients will be able to lead healthier and more productive lives.
The author expresses gratitude to Dr. Eric Klawiter of Massachusetts General Hospital for his assistance in the approach of treatment of MS as well as to Mr. Dave Bexfield of ActiveMSers.com for his assistance in the cooling vest market. Also, the author also expresses gratitude to Dr. James Kozelka of Associates in Neurology, Dr. Christine Mermier of the University of New Mexico, Dr. Rosalind Kalb of the National Multiple Sclerosis Society, and Dr. Bob Collings for their assistance in the editing process. This project was performed at the request and funding of the Collings Foundation of Stow, Massachusetts.
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