Health & Wellness

When they think about the effects of temperature on their symptoms of multiple sclerosis, most people think about heat. Heat sensitivity is very common in MS. In fact, more than 60 to 80 percent of individuals living with MS will have ill effects from the heat. Heat can cause an increase in any of the symptoms you are currently experiencing from your MS or bring new symptoms to the surface.

It can even make you feel as if you are having an exacerbation. While heat does not cause an exacerbation, it can cause something called a “pseudo-exacerbation” (a temporary worsening of symptoms without an increase in disease activity). As a result you can feel weaker, have more sensory symptoms, feel more fatigued or have changes in your vision, all of which can significantly affect how you function.

The reason behind this phenomenon lies in the ability of a nerve axon to transmit an impulse from the brain to the periphery. This transmission is negatively affected by the loss of myelin in the brain and spinal cord. Nerve impulses are slowed or lost when myelin is destroyed in MS. Nerve impulses are best transmitted at our normal body temperature (usually around 98.6 degrees Fahrenheit). When the system is heated up – whether because of the temperature of the air or by internal means (when we exercise or have an infection) – the impulses are slowed, depleted, or blocked, causing further difficulty in the messages getting to the appropriate destination.

Discussed much less frequently is the relationship of cold temperatures and their effect on MS symptoms. This phenomenon is not as common as heat sensitivity, but it can be equally as influential. According to one source, 10 percent of individuals with MS reported a deterioration of their symptoms when exposed to cold temperatures. Many people report that their spasticity (abnormal muscle stiffness) increases in the cold and others report that their sensory symptoms like numbness, tingling or the “MS hug” worsen.

Little is Known

Potentially, any MS symptom can worsen in the cold and, as with heat, any change in your symptom profile can have a significant effect on your functioning. We don’t know the exact mechanism of why this happens, but we do know that when a nerve axon is cooled down the impulses along that nerve are slowed. In a neurological system that already has transmission problems this cooling may cause the impulses to reach a threshold where they are further impaired or blocked. As with heat sensitivity, these symptoms are temporary and will resolve when the system returns to its usual temperature.

Unfortunately, there is little research in the area of cold sensitivity in MS. In one study performed at the University of Florida, body temperatures were lowered by placing MS patients in a cold water bath (75.2 degrees Fahrenheit) for 20 minutes. The results showed that spasticity in these individuals did increase. Another interesting study was done comparing individuals with MS performing a physical therapy program in a warm climate (Spain) versus a cold climate (Norway). Individuals who exercised in a warm climate had increased walking distance and reported less exertion after walking as compared to individuals who worked out in the colder climate. Individuals in this study did not have a history of heat intolerance.

Some individuals living with MS may have problems regulating their own body temperature because of impairments in the neural control of the autonomic nervous system. The autonomic nervous system is the part of our nervous system that controls all those functions that we don’t have to think about: our heart rate, our blood pressure, our sweating response and our body temperature. It has been documented that blood pressure and heart rate are not always reliable measures for monitoring exercise response in some individuals who have been diagnosed with MS for a long time or have many impairments.

Additionally, the sweat response can be abnormal in 40 to 60 percent of persons living with MS. Our sweat response is one way our bodies try to keep us cool. Temperature regulation is another area that can be affected. You may run a lower “normal” body temperature or may feel cold or hot more quickly than others. Being aware that your body may not have the same responses to heat or cold it previously did or that your response is different than others exposed to the same conditions is important to effectively manage your symptoms.

Symptom Management Tips

Although we do not know all the science behind it, cold sensitivity in MS does exist. If you are cold sensitive it is important to limit your exposure to cold or plan appropriately. If you are subjected to the cold, here are some tips to keep your body from experiencing the negative effects:

• Get moving! Moving your body generates internal body heat and that can help minimize the effect of the cold. Even sitting and doing arm exercises can start to heat up your body’s furnace and keep symptoms at bay.

• Drink a warm drink or eat a hot meal. This too can warm your body from the inside out.

• Plan for colder temperatures by dressing appropriately. Layering clothes is a great strategy because if your temperature increases you can easily remove layers to be comfortable. You can purchase hand warmers or sock warmers if your extremities are cold sensitive.

A word of caution: If you are using heating pads or getting close to a heat source and you have problems with your sensation, then you will need to visually inspect your skin to make sure you are not causing a burn. Never fall asleep on a heating pad or use heat for a prolonged period of time.

• Discuss your temperature sensitivity with your healthcare professionals. They can help guide you to determine if your increased symptoms are truly from the cold or because of another medical reason such as poor circulation or a problem with your thyroid. Ruling out other conditions that may be the source of a symptom is key in your overall health management. MS may not be the cause of every symptom you experience.

• Adjust your home’s thermostat accordingly. Keeping it too warm in your home may be equally detrimental as being too cold.

• Try to get some sunshine even if the temperature outdoors is cool (dress appropriately). Sunshine helps boost your Vitamin D levels which are often low in individuals with MS. Low Vitamin D levels can add to the symptoms that are experienced with MS such as fatigue, generalized muscle pain and weakness.
It is important to be in tune with your body’s response to temperature – cold or hot – so you can take the necessary actions to minimize unwanted symptoms and have the best quality of life no matter what the thermometer says.
 
Patty Bobryk is an MS-certified specialist in physical therapy and an assistive technology practitioner who works exclusively with persons with MS at the Orlando Health MS Comprehensive Care Center of Central Florida. She is the former chair of the International Organization of Multiple Sclerosis Rehabilitation Therapists and is the current Secretary for the Consortium of Multiple Sclerosis Centers.