Coping with High Temperatures & Sun

   

Think of heat as ‘energy expenditure’ - the body's efforts to cope with heat can consume limited physiological reserves, so activities that were manageable in cooler weather may trigger symptoms. For someone with ME, a hot day can effectively add "hidden exertion" to everything else. Poor sleep due to heat can further exacerbate symptoms.

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Why heat is such a big issue in ME

Many people with ME describe heat as feeling like an additional stressor that their bodies must actively manage. Because energy production and autonomic regulation may already be impaired, even modest increases in temperature can feel disproportionately exhausting.

This is why practical measures such as staying in cool environments, using fans or air conditioning, cooling garments, maintaining hydration and electrolytes (if appropriate), and pacing more carefully during hot spells can make a significant difference.

One thing that has become more recognised in recent years is that heat intolerance in ME often isn't simply "being sensitive to hot weather."

It can be related to:

• Orthostatic intolerance
• Dysautonomia
• Blood pooling
• Impaired temperature regulation
• Reduced ability to dissipate heat

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Many people with ME find that direct sun, warm rooms, hot showers, and even sitting outdoors can count as exertion and contribute to PEM. The current warm weather in Ireland and most of Europe may be affecting you.

Here’s a summary of strategies to help you during this hot weather followed by more detailed guides further below.

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• Stay indoors during the hottest part of the day (10am–6pm if possible).

• Pace more than usual, because heat itself can be an exertion and may trigger symptom worsening or PEM.

• Wear loose, lightweight clothing and a wide-brimmed hat outdoors.

• Keep well hydrated and consider electrolyte replacement if heat causes heavy sweating or worsens orthostatic symptoms.

• Keep curtains and blinds closed on sun-facing windows during the day.

• Use fans, cooling pillows, cooling blankets, cold flannels, water sprays, or a cold water bottle in bed.

• Watch for signs of heat-related illness: headache, nausea, dizziness, confusion, muscle cramps, or feeling faint.

• Cool the pulse points

Rather than trying to cool your whole body:

- Cold flannel on the neck

- Cool wrists and forearms

- Feet in cool water

- Cooling scarf or neck wrap 

 

These methods often reduce heat stress with less effort than a full shower.

 

• Create a cool room

- Close curtains/blinds during the day.

- Close sun-facing windows while it's hotter outside.

- Open windows in the evening and overnight when temperatures fall.

- Turn off unnecessary electronics that generate heat.

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Think about your medications

Some medicines, including certain antidepressants and antihistamines, can worsen heat intolerance or affect temperature regulation. If you're struggling significantly, it's worth discussing with your GP or pharmacist. Please do not discontinue or change any medications without first consulting your healthcare provider.

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Be cautious with direct summer sun

Many people with ME report that it's not just the temperature but the direct sunlight itself that can be draining. Sitting in shade, using UV-protective sunglasses, and limiting exposure can sometimes make a substantial difference. Community feedback frequently describe heat and sun as triggers for crashes and PEM.

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Heat Intolerance Resouces

Heat Intolerance Tips from ME/CFS San Diego group

https://drive.google.com/file/d/1kb6i_SoumgRC3VEzEnbylbbbwWFP5zpJ/view

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Tips on how to cope in the heat from the ME Association UK

https://meassociation.org.uk/medical-matters/items/how-to-cope-with-a-heatwave-if-you-have-me-cfs/

A useful way to think about it

Many people without ME treat heat as merely uncomfortable. For many people with ME, heat functions more like an additional workload. The body is simultaneously trying to:

• Maintain temperature,
• Maintain blood flow to the brain,
• Perform normal activities,

and that combined demand can exceed available capacity, leading to symptom worsening and sometimes PEM.

This is one reason many people with ME report functioning significantly better in cool, stable temperatures than during hot weather, even when their activity level hasn't changed.