Why Hot Weather Can Trigger Flares & Simple Strategies to Stay Cool
For people with Ehlers-Danlos syndrome (EDS)/hypermobility spectrum disorder (HSD), mast cell activation syndrome (MCAS), or dysautonomia (including postural orthostatic tachycardia syndrome/POTS), hot weather can feel like a full-body flare just waiting to happen.
Heat doesn’t just cause discomfort—it can overwhelm systems in the body that are already under strain, leading to significant symptoms that are often misunderstood or delayed in onset.
Heat Can Trigger Chaos in the Body
EDS/HSD: Muscles may fatigue more quickly in the heat, and connective tissue laxity or chronic pain may worsen with prolonged heat exposure.
MCAS: Hot weather and UV (ultra-violet) rays from the sun can overactivate mast cells, triggering a cascade of symptoms such as flushing, hives, headache, fatigue, or gastrointestinal (GI) issues.
Dysautonomia: Heat can disrupt the autonomic nervous system’s ability to manage temperature regulation, blood pressure, heart rate, blood flow, and blood volume—leading to dizziness, rapid heart rate, nausea, or fainting.
Delayed Reactions Are Common
Not everyone reacts to heat immediately. For some people, flares may show up hours later—or even the next day—making it harder to pinpoint heat as the cause of symptoms.
Delayed reactions may include:
Fatigue later that day
Trouble sleeping that night
Nausea, bloating, or abdominal pain a few hours later
Brain fog or a headache hours later
Because symptoms can be delayed, it’s easy to overdo it without realizing the consequences until it’s too late.
Proactive Cooling Strategies That Can Help
These small adjustments may help reduce the risk of flares caused by heat exposure:
Wearing mesh-backed, breathable shoes
Using a personal misting fan or neck fan
Wearing a hat or UV-protective clothing
Freezing a half-full water bottle sideways; top it off later with cold water and electrolytes
Installing reflective or tinted window shades in your car
Trying cooling towels or neck wraps
Remember, cooling strategies aren’t just about comfort—they’re part of managing your condition.
Don’t Wait for a Flare to Start Managing Heat
For people with chronic illnesses that impact the autonomic nervous system, connective tissue, or immune system, heat isn’t harmless—it can destabilize your whole body.
Learning to spot your own patterns, staying proactive, and implementing heat adaptation strategies can go a long way for preventing flare-ups.
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PMID: 33573161; PMID: 35967442; PMID: 26723547; doi: 10.1002/ajmg.c.31951
Disclaimer: This blog post is for informational purposes only and shall not be construed as behavioral health or medical advice. It is not intended or implied to supplement or replace treatment, advice, and/or diagnosis from your own qualified healthcare provider.