Learn more about the causes of both heat and cold sensitivity, plus what you can do.
Multiple sclerosis (MS) is a chronic disease that damages the central nervous system (CNS). The CNS consists of the brain, spinal cord, and optic nerves. In MS, the body's immune system mistakenly attacks myelin, the protective layer surrounding nerve fibers. This, in turn, leads to demyelination, which creates lesions (scar tissue) throughout the CNS. Lesions impede the seamless flow of electrical signals along nerves, resulting in various symptoms experienced by MS patients, including but not limited to; heightened sensitivity to temperature changes, weakness, fatigue, vision problems, and cognitive difficulties.
Below, we dive into the causes of both heat and cold sensitivity, and what you can do.
Causes of Temperature Sensitivity With Multiple Sclerosis
People with MS often experience temperature sensitivity for two key reasons:
- Demyelination and disrupted signaling
Demyelination damages nerve fibers, making them hypersensitive to temperature changes. These damaged nerves may send exaggerated or erratic signals to the brain, hindering the body's temperature regulation abilities. Nerve fibers called axons play a crucial role in temperature sensation. When damaged in MS, the perception of temperature changes may intensify. Additionally, MS can cause direct damage to the axons, the long, threadlike portions of nerve fibers responsible for conducting signals. This damage further disrupts the transmission of temperature information to the brain.
- Hypothalamic dysfunction
The hypothalamus, a small but vital region of the brain, acts as our internal thermostat monitoring core body temperature and coordinating responses to keep it stable. MS lesions forming within the hypothalamus can disrupt this delicate thermoregulatory function, which may lead to difficulty regulating skin temperature. The result: difficulty adapting to hot or cold conditions.
Heat Sensitivity
Many individuals with MS experience significant challenges with heat sensitivity. Temperature increases can have the following effects on MS patients:
- Worsening of existing MS symptoms
Existing MS symptoms such as weakness, fatigue, vision problems, cognitive difficulties, and spasticity (muscle stiffness) may worsen in hot environments. Heat can also exacerbate cognitive difficulties, making it harder to concentrate, focus on tasks, or process information quickly. The effects of heat can make managing everyday tasks and activities increasingly difficult.
- Uhthoff's Phenomenon
This refers to a temporary worsening of MS symptoms specifically caused by an increase in core body temperature. Even a slight rise can trigger Uhthoff's phenomenon due to the slowed nerve signal conduction along damaged fibers. Common triggers include exercise, hot weather, hot baths or showers, and fevers.
- Impaired cooling mechanisms
MS can disrupt thermoregulatory processes, such as sweating and blood vessel dilation, which help dissipate heat. This impairment increases the risk of overheating, particularly in hot and humid environments, which can lead to further worsening of MS symptoms.
- Heatstroke risk
In extreme cases, prolonged exposure to excessive heat stress can lead to heatstroke. This life-threatening condition occurs when core body temperature exceeds 104°F (40°C). Symptoms may include confusion, seizures, loss of consciousness, and hot, dry skin. Seek immediate medical attention if you suspect a heatstroke.
Strategies for Managing Heat Sensitivity in MS
- Environmental control
Maintain a comfortable temperature at home and work with air conditioning, fans, and evaporative coolers. If air conditioning is unavailable, look into government assistance programs or local charities that may offer support for acquiring cooling equipment during hot weather to reduce heat exposure.
- Smart clothing choices
Wear lightweight, loose-fitting, and breathable fabrics like cotton or linen. Light colors reflect heat, making them preferable to darker shades. Wide-brimmed hats also offer additional sun protection.
- Hydrate
Drink plenty of cool fluids throughout the day, even if you don't feel thirsty, to prevent dehydration. Water is best, and you can even add fruit slices or herbs for more flavor. Avoid sugary drinks, caffeine, and excessive alcohol, which can cause dehydration.
- Timing is everything
Limit outdoor activities, exercise, and errands to the coolest times of the day, such as early morning or evening. Avoid strenuous workouts during heat waves.
- Consider cooling aids
Wearable options like cooling vests, neck wraps, and bandanas can provide added relief, especially if pre-chilled in a refrigerator or with ice packs. Cooling pillows and bed pads can help promote comfortable sleep at night.
- Take cool baths and showers
Taking a short, cool shower or bath can quickly lower your core body temperature. But be sure to avoid extremely cold water, as the initial shock can temporarily raise body temperature.
- Dietary adjustments
Opt for cooling foods like fruits, vegetables, and chilled soups. Avoid large, hot, or spicy meals that can contribute to increased body heat generation.
- Talk to your healthcare team
Discuss heat intolerance with your neurologist or healthcare provider. They may suggest adjustments to your existing MS medications or offer additional strategies to help you cope.
Cold Sensitivity
While heat sensitivity is more prevalent, some individuals with MS experience challenges with cold sensitivity as well. Cold exposure can lead to some common symptoms like:
Strategies for Managing Cold Sensitivity
- Layer up
Wear multiple layers of warm clothing, including hats, gloves, scarves, and thick socks. Use thermal base layers for extra myelin. Consider materials like fleece or wool for optimal warmth.
- Prioritize warm foods and drinks
Consuming warm beverages like tea or broth and eating warm meals can help raise your core body temperature. Soups or stews are particularly comforting on cold days.
- Invest in heating devices
Use heating pads, electric blankets, space heaters, or heated clothing to combat chills. If you have Raynaud's Phenomenon, heated gloves and socks can be especially beneficial.
- Partake in gentle exercise
Regular physical activity may help improve circulation and reduce cold sensitivity. Focus on exercises that promote flexibility, strength, balance, and aerobic fitness, such as walking, chair exercises, yoga, water-based exercises (like swimming or pool therapy), and modified exercises that take into account any mobility restrictions.
- Take warm baths
Soaking in a warm bath can increase blood flow and relieve muscle stiffness from cold temperatures. Water-based exercises in a temperature-controlled pool can be especially beneficial, as the water reduces impact on joints and provides a comfortable environment for movement. Be careful not to expose yourself to prolonged hot water though, as it can raise the core body temperature and potentially worsen MS symptoms.
- Manage cold-sensitive medications
Talk to your doctor about any medications that might worsen cold sensitivity, including certain types of blood pressure medications that can affect circulation. Your doctor may suggest alternative treatment options or discuss ways to manage potential side effects.
The Bottom Line
Successfully managing temperature sensitivity (aka thermoregulatory dysfunction) is a crucial aspect of living with MS. Implementing lifestyle changes, strategically using cooling or warming aids, and understanding how your body responds to temperature fluctuations can significantly improve your quality of life. While some temperature sensitivity is common even in those without MS, when it impacts your daily life and wellbeing, discussing it with your healthcare team (doctor, occupational therapist, physical therapist) is an important step.
And remember, your geographic location can play a role in managing temperature sensitivity with MS. People living in hot, humid climates may face greater challenges with heat sensitivity, while those in colder regions might experience more difficulties with cold. Understanding the typical weather patterns in your area can help you tailor your management strategies.
It's important to listen to your body and recognize when you're getting too hot or too cold. Take breaks, find a cooler or warmer place, and adjust your activity level as needed.
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