Fibromyalgia is a chronic pain disorder characterized by widespread musculoskeletal pain that persists for an extended period, often described as an all-over ache or burning sensation. This condition is also associated with chronic fatigue, unrefreshing sleep, and cognitive difficulties, sometimes referred to as “fibro fog”. Experts believe that the underlying mechanism involves a disorder of the central nervous system (CNS), leading to abnormal pain processing, which is known as nociplastic pain. The CNS essentially becomes hypersensitive, causing the brain and spinal cord to overreact to both painful and non-painful signals.
The Connection Between Fibromyalgia and Temperature Sensitivity
Fibromyalgia is strongly associated with temperature sensitivity, frequently including an intolerance to heat. For many people with this condition, exposure to high temperatures or humidity can trigger a significant worsening of symptoms, including increased pain and fatigue. Surveys suggest that up to 80% of individuals with fibromyalgia report that changes in ambient temperature negatively affect their symptoms. Heat intolerance is defined as the body’s diminished ability to regulate its core temperature effectively when faced with external heat.
This difficulty in maintaining a stable internal temperature means that even a mild rise in environmental heat can lead to a feeling of being severely overheated. Research indicates that people with fibromyalgia have a reduced pain threshold to heat stimuli, meaning temperatures that cause only mild discomfort in others can be perceived as painful or burning. This issue is prevalent and disruptive, often manifesting as dizzy spells, nausea, and an escalation of general fibromyalgia symptoms.
Understanding Autonomic Dysfunction in Fibromyalgia
The underlying cause of heat intolerance in fibromyalgia is often attributed to a disruption in the Autonomic Nervous System (ANS), frequently called dysautonomia. The ANS is the body’s involuntary control center, managing functions such as heart rate, blood pressure, digestion, and thermoregulation, or body temperature control. In fibromyalgia, the CNS hyperactivity appears to impair the efficient functioning of the ANS.
Specifically, the sympathetic nervous system, the “fight or flight” branch of the ANS, tends to be overactive, which can impede natural cooling responses. Cooling mechanisms like sweating and vasodilation—the widening of blood vessels near the skin to release heat—may not be executed efficiently. This impairment can result in abnormal sweating, where a person may sweat excessively or not sweat enough to cool their body down.
Scientific detail points to structural differences in the skin’s blood vessels, particularly specialized connections called arteriovenous (AV) shunts found in the hands, feet, and face. These shunts adjust blood flow in response to temperature changes, but studies suggest that people with fibromyalgia may have extra temperature-sensing nerves located along these vessels. This heightened sensory input contributes to an exaggerated perception of heat, making the person feel instantly overwhelmed by warmth. The connection between fibromyalgia and related conditions like Postural Orthostatic Tachycardia Syndrome (POTS), a form of dysautonomia, also contributes to heat-related issues.
Strategies for Managing Heat Intolerance
Managing heat intolerance requires proactive steps focused on minimizing exposure and supporting the body’s thermoregulation system. Staying properly hydrated is important, involving consistently sipping water throughout the day rather than drinking large amounts at once. Some people may also benefit from increasing their salt or electrolyte intake, especially if they experience symptoms of dysautonomia like dizziness upon standing.
Environmental modifications and cooling aids are effective in controlling heat exposure. When venturing outdoors, schedule activities for the cooler parts of the day, typically before mid-morning or after late afternoon, to avoid peak heat hours.
Cooling Techniques
- Use air conditioning during warm periods or employ fans in conjunction with a bowl of ice to create a makeshift cooling zone.
- Wear lightweight, loose-fitting clothing made from breathable natural fabrics like cotton.
- Apply cooling aids, such as dampened towels, cooling vests, or gel packs, to the wrists or neck to target areas where blood vessels are close to the surface.
- Take a cool, not cold, shower to gently lower the core body temperature without shocking the system.
It is helpful to recognize the early signs of overheating, which may include a rapid onset of increased pain, brain fog, or dizziness, and immediately move to a cool environment to rest.