Heat Intolerance in EDS, HSD, and Hypermobility: Why It Happens and What Helps

Estimated reading time: 13 minutesHeat intolerance is the name for what happens when the body struggles to regulate its own temperature in response to high temperatures.

If you have hEDS, HSD, or POTS, this may be a familiar experience. Especially as we experience high heat warnings.

The autonomic nervous system controls how the body cools itself, and when this system is impacted by conditions like dysautonomia and mast cell activation syndrome (MCAS), this can result in a number of increased issues like dizziness, fatigue, and more.

I’ve always struggled with heat since I was a child. I remember heat rash or prickly heat starting around the age of 6, together with dizziness and sickness.

My doctor prescribed eating lettuce covered in salt – he must have been ahead of his time. No one mentioned hypermobility, EDS, and common co-occurring conditions for a very long time.

As an adult, saunas and heat rooms are a big no, causing fainting. Hot showers or baths also make me unwell (the weird thing, of course, is that because I always feel cold, I love hot showers, but I’ve learnt the hard way not to have them).

As summer approaches, people love being out in the sun. I do too – but my body doesn’t agree.

Headaches, fatigue, dizziness, and palpitations often show up. You’ll find me in the shade and always wearing a hat if possible (of course, you’ll also see me wearing a woolly hat in the cold weather because the cold gives me headaches too!).

But what causes these reactions to heat, and what practical solutions are there to help manage them?

This blog explores heat intolerance, and our wonderful Zebra Club community has stepped up with a wealth of knowledge and lived experiences to help us understand how an hEDS/HSD body can navigate heat.

What is heat intolerance?

Heat intolerance is a reduced ability to maintain normal body temperature when exposed to heat. This can be caused by disruption of the autonomic system that controls sweating and blood vessel dilation.

Heat intolerance is also called heat sensitivity, temperature intolerance, or thermoregulatory dysfunction. These terms all describe the same difficulty regulating the body’s response to higher temperatures.

Our bodies work to maintain a core temperature within a couple of degrees of 37°C (98.6°F) to enable normal cellular function. This process, called thermoregulation, is controlled by the autonomic nervous system (1).

When exposed to cold temperatures, blood vessels in the skin constrict to retain heat, while the body generates additional warmth through shivering (1).

Conversely, in warm conditions, these skin vessels dilate to release heat through convection, while sweating provides cooling through evaporation (1).

Heat intolerance occurs when our bodies struggle to maintain this temperature regulation, particularly in warmer environments (2). While high environmental temperatures can pose challenges for everyone, those of us with compromised thermoregulation face greater risks (1).

This impaired temperature control can result from various factors, including certain medications and disorders that affect the autonomic nervous system.

Symptoms of increased body temperature leading to heat exhaustion

Heat exhaustion can happen when heat intolerance goes unmanaged and the body’s cooling systems are overwhelmed. Without intervention, this can progress to hyperthermia and, in severe cases, heat stroke.

Symptoms to watch out for include fatigue, irritability, thirst, tachycardia and postural fainting, weakness, cramps, headaches, dizziness, low urine output, and nausea or vomiting (1).

Please seek medical care, especially with new or significant symptoms. This post is not medical advice. Heat intolerance can be a symptom of various medical conditions and needs proper evaluation by a healthcare professional. If you experience severe heat-related symptoms or sudden onset of heat intolerance, please consult your doctor promptly.

In the hypermobility community, the most commonly discussed contributors to heat intolerance are autonomic dysfunction (dysautonomia), mast cell activation, and the effects of certain medications on sweating.

In one study that was trying to compare HSD and hEDS, 45% of participants with HSD and 30% of those with hEDS self-reported experiencing heat intolerance (3).

Dysautonomia and heat intolerance

Dysautonomia is a term for conditions where the autonomic nervous system, which controls automatic body functions including temperature regulation, does not work correctly.

Since thermoregulation, or the ability of the body to regulate temperature, is an autonomic function, it makes sense that this may be impacted when we have autonomic dysfunction or dysautonomia.

Research in the hEDS and HSD population has found that dizziness related to heat is a significant predictor of fatigue severity, suggesting the two are closely linked through autonomic dysfunction (4)

Sudomotor dysfunction means the nerve signals that trigger sweating are disrupted, so the body may overheat without producing enough cooling sweat, or may sweat excessively and unpredictably. Sudomotor function can be affected by dysautonomia. In fact, sweating too much, sweating too little, and temperature intolerance are a result of this dysfunction and are considered key manifestations of dysautonomia (5).

Many people with dysautonomia experience heat and cold intolerance together because the autonomic system struggles to regulate temperature in either direction.

For people with POTS, heat is often a flare trigger, not just a discomfort. Heat can cause peripheral vasodilation (enlargement of blood vessels) to the skin in an attempt to release heat. This can compound with already impaired venous return, reducing blood return to the head and heart and making orthostatic intolerance and symptoms worse (5).

MCAS and heat intolerance

Mast Cell Activation Syndrome (MCAS) is a condition where mast cells, immune cells found throughout the body, release chemical mediators in response to triggers that would not normally cause a reaction.

Mast cells play many roles in the body and have receptors for a variety of pathogens, immune cells, and physical stimuli like temperature (hot or cold) (6).

When the mast cells go haywire, the mast cells can respond to things that are not normally threats. Heat (and cold) is a known trigger for mast cell activation and can increase discomfort, cause, or make symptoms worse (6, 7).

Which medications can make heat intolerance worse?

Some antihistamines that are often used to manage MCAS (and others) can contribute to heat intolerance because they decrease sweating (Diphenhydramine) (7). If this is a concern for you, please speak with your medical team.

Of note: Other medications that can contribute to heat intolerance include SSRIs and SNRIs, Beta-blockers, Aspirin, and more (7). Discussing this with your doctor, paying attention to cooling strategies (see below), and hydration may be helpful.

Zebra Club community tips for managing heat sensitivity

We went to the experts – The Zebra Club Community! We asked them to share what they use to help manage heat when the temperatures start rising. These real-world tips come from people who understand the daily challenge of temperature regulation with hypermobility conditions.

1. Cooling Clothing and Fabrics

Choose Natural, Breathable Materials

Fabric choice makes a bigger difference than most people expect. Linen is the most-recommended option in the community — lightweight, breathable, and genuinely cooler than synthetics in real-world comparisons.

As community member Ash put it: “I was shocked a few years ago to find just how cooling and lightweight linen clothes are. I was on holiday to the beach and wore linen one day and polyester the next — the difference was crazy. Over the past couple of years, I have thrifted lots of linen summer items.”

BendyChristy, who manages POTS in a very hot, humid climate, adds important nuance: “Clothing is ideally minimal, loose fitting, white, thin linen, and thin cotton poplin, gauze, or voile. This makes it tricky to shop online. When shopping online watch out for linen clothing with polyester liners, a polyester liner totally defeats the purpose, rip it out and wear full coverage skin colored underwear.”

She also notes that “the weave and weight of the fabric can be just as important as the fabric content.”

Helene layers light natural fibres for the same reason: “Wear light natural fibers, wider clothes in layers that can easily be taken off (or put on because I get cold easily too).”

On the go, sun hats and hair management come up repeatedly.

BendyChristy will “whip my hair into a bun just to walk from the air-conditioned car to the air conditioned building,” and Lucy swears by big sun hats and “chub rub shorts” if skin friction is an issue.

2. Bedroom and Sleep Solutions

The bedroom is where many community members have put the most effort. Ian’s simple rule: “Pull the covers back on your bed, let the bed breathe during the day. The bed holds the heat.”

treesandbees has a home-specific approach: “I hope everyone in the UK red warning zone has their curtains drawn and tucked in around the window if possible, or blinds closed. I live in a south facing flat and find this really helps reduce the internal temperature.”

For bedding, the community has found some creative solutions.

Caroline discovered cooling weighted blankets: “I just found cooling weighted blankets which are really helpful. They conduct heat away from the body but also give us the weight sensation we need to fall asleep.”

Hen uses a pet cooling mat: “Also have a pet cooling mat by the bed which I sling over myself if needed for immediate cooling effect. The cat wouldn’t use it — more fool him!!”

DanielaS recommends a silk duvet for natural temperature regulation, and Ian uses bamboo sheets. For the most extreme nights, F takes inspiration from time spent in South Africa: “When I lived in South Africa (no aircon in those days), I would spray a bed sheet with water and freeze that to sleep under.”

Mischa has developed a multi-step nighttime routine: “I love to rinse my hair, and put it up in a bun still quite wet. It helps me stay cooler. I have a small, clip-on fan blowing directly on me, and can adjust the angle and speed any time during the night.”

3. DIY Cooling Methods

When it comes to DIY solutions, ice and cold water remain unbeatable. Laura relies on frozen hot water bottles: “Frozen hot water bottle is my go to (great for a long lasting pain relief ice pack too). I have a couple filled on rotation in the freezer. It’s amazing how long they last 🧊”

Daisy has a similar system: “My hack is to go to bed with a couple of ice packs wrapped in tea towels. Like a hot water bottle except cold. I have also been making flavoured herbal teas slightly sweetened and then cool in the fridge — ie home made ice tea.”

F also recommends freezing wheatbag heat packs: “Wheatbag heat packs work brilliantly chilled in the freezer for at least 12 hours.”

BendyChristy makes the case for plain ice above all else: “I have tried lots of cooling gadgets over the years but nothing beats good old ice! Every other gadget I’ve tried is warm after 15 minutes, but this can be refilled with ice from any place that sells drinks.”

A fan with a bowl of ice placed behind it is another community favourite: “Use fans in every room. You can put a bowl of ice behind the fan so the air it blows is cooler.”

Water-based cooling is equally popular. Jan soaks her feet in cold water, Marnie runs cold water over her wrists — “my dear Mum always said to run cold water over your wrists” — and Allison turns the shower temperature down as low as she can stand it when she’s overheated.

J adds: “Frozen washcloth on the back of the neck and frequent cool showers can be helpful.” Spray bottles of water appear in almost every community member’s bag.

As littlebee puts it: “Very simple but I always have a tiny spray bottle with water in my bag and am constantly misting my face and arms with water, it absolutely works wonders — and my friends and family love me for it as well 😂”

Rachael carries one too: “Carrying around little spray bottles of water, to squirt all over, lovely in a breeze, having to embrace frizzy hair!”

4. Specialized Cooling Products

Neck cooling is a particular priority. Katie keeps cooling neck rings in the freezer: “I discovered these cooling neck rings last summer and I love them, I keep a few in the freezer.”

Helene uses a scarf with gel pellets: “I also have a scarf with gel pellets in it that absorb a lot of water and will cool my neck for hours by the evaporation of the water.”

Rachael uses cooling cloths around the neck: “Makes me think of Susan Sarandon in Thelma and Louise do this with a scrap of her scarf.”

Portable fans, neck fans, and cooling vests are also widely recommended. Mischa adds an Embr Wave wristband to her toolkit alongside cold wrist rinses. Bethany uses a cooling vest: “It’s been very helpful in hot situations like ball games.”

5. Hydration and Internal Cooling

Hydration is so important. Nutritionist Lorna Ryan wrote a great blog for us on hydration, electrolytes, and POTS.

The community is clear that electrolytes matter as much as water quantity. As Ash explains: “I up my hydration considerably. It’s amazing how being dehydrated can cause such bad temperature dysregulation.”

Mischa drinks electrolyte drinks throughout the day, Hen uses metal water bottles with lots of ice to keep drinks cooler for longer, and Lucy prefers cool rather than ice-cold beverages: “A lot to drink but not ice cold, e.g. cold fruit or herbal tea.”

6. Home Environment Management

Window management comes up more than almost anything else. The consistent advice: keep windows and curtains closed during the day while it is hotter outside than inside, then open them in the evening to catch cooler air.

As A puts it: “Also, keep the windows closed and covered during the day and then open them in the later evening to (hopefully) catch the breeze. Close them up again in the morning.” A also recommends a practical food tip: “Don’t cook inside. Make cold meals or barbecue outside.”

Mischa has found a creative insulation hack: “Some companies (Misfits) deliver groceries in reflective bubble wrap bags as insulation. I take those bags and tape them together to cover the inside of the windows. This works the same as Reflectix.” Other members discussed using aluminum foil to cover windows.

Helene has invested in her outdoor environment too, planting climbing plants on walls and around the garden. She notes: “People always remark on how cool our house is on hot summer days.” She also uses misters on her patio, a large awning for shade, and manages curtains strategically: “On sunny summer days we keep the curtains and windows closed as long as the temperature outside is higher than inside.”

Hen shared a comprehensive home cooling strategy: “We keep the house temperature as low as possible (no air con. We have shutters on our windows and keep them closed during the day in summer. We open windows at night to let cool air in but close them during the day -to keep hot air outside- and use fans.”

7. On-the-Go and Natural Cooling Solutions

Many of our community members have built up a collection of cooling strategies they can use wherever they are. Small portable items often make a huge difference.

Spray bottles appear again and again in the recommendations. Helene suggests: “Have a fine misting spray bottle with peppermint essential oil in the water.” The cooling effect of peppermint is something several members swear by. Ash shares: “I also find the essential oil, peppermint, to be very cooling.”

Mischa has developed her own version: “I spray alcohol with a drop or two of peppermint on my neck, under my arms, or on my back.”

Even plain water can be surprisingly effective. As littlebee explains: “Very simple but I always have a tiny spray bottle with water in my bag and am constantly misting my face and arms with water, it absolutely works wonders — and my friends and family love me for it as well 😂”

When spending time outdoors, creating shade wherever possible is a common strategy. Lucy recommends a “Beach shade shelter tent for beach or garden” and also carries “an umbrella to create shade.” Practical sun protection is important too, with Lucy’s simple but effective recommendation: “Big sun hats.”

For those who need longer-lasting cooling while out and about, Ash recommends cooling towels: “I use cooling towels (Frog Toggs).” These can be especially helpful for walks, outdoor events, or travel when access to air conditioning is limited.

Some members find that how they position themselves can make a noticeable difference. Fiona Brown says: “I find sitting rather than standing in the sun and being hydrated.” Small adjustments like seeking shade, sitting when possible, and staying on top of hydration can help reduce the impact of heat.

Others have discovered creative cooling techniques that pull double duty for pain management. Rachael shares: “More for hand pain, but it is cold, a plastic tub of rice kept in the freezer is so lovely to sink swollen sore paws into.” It’s a simple idea that provides both cooling relief and comfort for sore, swollen hands.

8. POTS-Specific Cooling Strategies

For those managing POTS with compression garments, the conflict between compression and cooling clothing is real.

Janinekits has found a solution: “For POTS I really need to wear my waist high compression tights, especially on hot summer days. But unfortunately it diminishes the cooling effect of flowy, cooling clothing. Wetting my legs under the shower while wearing the compression tights really helps. I do it a few times a day.” She also combines multiple cooling methods: “I wear one cooling scarf around my neck and one around my wrist. And instead of a heating pad at the foot of the bed, in summer I have a cooling pad meant for pets at the foot of my bed.”

9. Planning and Prevention

For many community members, planning in advance is the most effective strategy of all. BendyChristy’s approach in her hot, humid climate is direct: “My number one rule is ‘stay inside’! Not very practical but there you have it; every building in my climate has air conditioning. From June to November I go from air-conditioned house to air-conditioned car to air-conditioned building.”

Helene sets a personal temperature threshold: “On hotter days (above 22 Celsius) I just don’t go outside.” When camping, she researches shade locations on Google Maps before booking.

Community Wisdom: The Bottom Line

The most important advice from our community? Listen to your body and don’t be afraid to prioritise your comfort. Heat intolerance with EDS and dysautonomia requires creative solutions and planning ahead, but with the right strategies you can stay more comfortable — and the community has proved there is no shortage of those.

FAQ

Does Ehlers-Danlos cause heat sensitivity or heat intolerance?

Heat sensitivity and heat intolerance are commonly reported by people with EDS and HSD. Dysautonomia, MCAS, and certain medications all contribute, and research shows both conditions experience disrupted temperature regulation. It is one of the most widely shared experiences in the community.

What is heat intolerance?

Heat intolerance is the body’s inability to maintain a stable temperature when exposed to heat. It is most often caused by problems with the autonomic nervous system, which controls sweating and blood vessel regulation. Also called heat sensitivity or temperature intolerance.

What causes heat intolerance?

Multiple conditions and medications can contribute to heat intolerance. In people with hypermobility, EDS, and HSD, it is often linked to autonomic nervous system dysfunction (dysautonomia), which can affect sweating and blood vessel regulation. POTS is one of the most common contributors. Certain medications may also impair the body’s ability to regulate temperature.

What does heat intolerance feel like?

People describe disproportionate fatigue, dizziness, palpitations, and an inability to think clearly, even in temperatures others find comfortable. For many in the EDS and POTS community, symptoms begin well below temperatures others consider hot or challenging.

Does POTS cause heat intolerance?

Yes. Heat causes blood vessels to dilate, worsening the blood pooling already present in POTS. This makes orthostatic symptoms including dizziness, palpitations, and fatigue more severe in warm weather, meaning heat is a common POTS flare trigger, not just uncomfortable.

Does heat make EDS or hypermobility worse?

For many people with hEDS and HSD, heat can worsen symptoms by triggering dysautonomia, POTS, and MCAS flares. Heat causes blood vessels to dilate, increasing fatigue, dizziness, and palpitations. It is a common flare trigger rather than a direct cause of EDS itself.

The same autonomic dysfunction that causes heat intolerance in EDS and HSD can also cause cold sensitivity. When the autonomic nervous system struggles to regulate temperature in either direction, both heat and cold feel more extreme and harder to manage than they would for most people.

Why have I suddenly become heat intolerant?

Sudden heat intolerance can be caused by new medications, worsening dysautonomia, hormonal shifts, or recent illness. If it has appeared or significantly worsened, it is worth discussing with your doctor to identify any contributing factors.

Jeannie Di Bon

Jeannie Di Bon is a movement therapist, educator and author specializing in hypermobility, Ehlers-Danlos Syndrome and chronic pain. She is the founder of The Zebra Club app and the creator of the Integral Movement Method.

Catherine Nation

Catherine Nation, MS, PhD, holds a Master of Science in Biological Sciences and a doctorate in Tropical Medicine and Parasitology. As Marketing Content Manager at The Zebra Club and a member of the hEDS community, she applies her scientific background to making complex research accessible and accurate.

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