Multiple Sclerosis (MS) is a chronic neurological condition affecting the brain, spinal cord, and optic nerves. For many individuals living with MS, warmer conditions can lead to a temporary worsening of their symptoms. This sensitivity to heat is a common experience, impacting a significant portion of the MS community. Understanding this relationship helps in managing the condition more effectively.
How Heat Influences MS
Heat sensitivity, often called Uhthoff’s phenomenon, affects 60-80% of individuals with MS. Symptoms temporarily worsen when the body’s core temperature increases, even by as little as 0.25°F to 0.5°F. This occurs because heat impacts demyelinated nerve fibers, a hallmark of MS.
In MS, the protective myelin sheath surrounding nerve fibers in the central nervous system is damaged or lost. This demyelination impairs the efficient transmission of electrical impulses along the nerves. When body temperature rises, conduction in these demyelinated nerves slows or blocks. This disruption temporarily increases MS symptoms, which typically improve once body temperature returns to normal. Factors like hot weather, exercise, fever, or a hot bath can trigger this increase.
Observable Symptoms of Heat Sensitivity
When core body temperature rises, a range of MS symptoms can become more pronounced. Fatigue is a commonly reported symptom, often feeling more draining than usual. Visual disturbances, such as blurred vision or other changes, may also occur.
Muscle weakness or increased spasticity can be experienced, making muscles feel less coordinated or stiffer. Balance issues or dizziness may arise, potentially increasing the risk of falling. Cognitive difficulties, including problems with attention, concentration, or a general “brain fog,” can also intensify. Sensory changes like increased numbness or tingling sensations in the arms and legs are possible.
Practical Approaches to Managing Heat
Managing heat sensitivity involves various strategies to keep the body cool and minimize symptom exacerbation. Environmental adjustments include staying in air-conditioned spaces during peak heat hours. Using fans, keeping curtains closed, and avoiding direct sun exposure can also help maintain a cooler indoor environment.
Personal cooling strategies offer direct relief. Wearing cooling vests, neck wraps, or other cooling garments with ice or gel packs can help regulate body temperature. Taking cool showers or baths, applying wet towels, or using a spray bottle with cold water for refreshing spritzes are also effective methods. Staying well-hydrated by drinking plenty of cool fluids throughout the day is important, while minimizing caffeine and alcohol intake, which can contribute to dehydration.
Clothing choices play a role in heat management. Opt for lightweight, loose-fitting clothes made from breathable fabrics like cotton, linen, or bamboo, as these allow for better air circulation and moisture-wicking. Light-colored clothing can also help reflect sunlight and keep you cooler.
Activity modification involves exercising during cooler times of the day, such as early morning or evening, or in air-conditioned environments or a pool with water temperatures under 85°F. Pacing activities and taking frequent breaks are also important to avoid overheating. Consulting with healthcare providers, including an MS provider or physical therapist, can offer personalized advice and help identify cooling equipment options.