Written in August 2022

The summer of 2022 saw two heatwave emergencies declared in England, with the first for a 2-day event where temperature records were surpassed and a high of 40.3°C was recorded (beating the previous 38.7°C from 2019). Although for the purposes of official climate records the thermometer must be in the shade, a thermometer in our garden read over 50°C in the sun, so in practical terms of actually being outside, it was hotter than a very very hot thing. It wasn't all bad news, however, as my car got turned into a dehydrator for these extra hot days. 
 

I was incredibly glad not to be working as I do not cope well with the heat at all, and I am prone to feeling too hot even when others are cold. My nervous system seems ill-equipped to regulate my temperature and my preference is to feel too cold rather than too hot (if I can't feel “just right” like Goldilocks). 

When I am too hot I am unable to cool down efficiently – after a session in the pool and a shower it can take me up to 3 hours to regulate to a comfortable temperature. When I get too cold it can take a similarly long time to regulate (and up to 8 hours for circulation to return to my toes due to Raynaud's on top of the neurobiological differences). 

This is supported by science; we can produce heat, conserve heat, or lose heat, but we have no biological mechanism for active cooling. Given that my system is most frequently in heat losing mode (I sweat just as much in the winter as in the summer), it can't cope with extra demands for losing more heat.

Our bodies know our core temperature and they defend that temperature, taking action to produce, conserve or to lose heat depending on how far we perceive our temperature to be moving from the 37.5°C norm. We have a margin of around half a degree before our systems take unconscious action. In menopausal people this margin disappears altogether, and whether there is a similar lack of margin in autistic or neurodivergent people would be an interesting question to research.*

There has been various research into the issue of heat sensitivity in autism, with one study finding that autistic people had a lower sensory threshold for heat (that is, they were less able to detect changes in heat) and another finding no difference in the thermal perception abilities of autistic vs. non-autistic people. 

Anecdotally, you will find a plethora of experiences reported, with a lot of autistic people unable to deal with wearing a coat in cold weather as they overheat or because they don't perceive the cold. On the other hand, there are a lot of autistic people who feel the cold badly, and who are incredibly sensitive to changes in temperature in either direction. In all cases, people report that their ability to regulate temperature and cope with changes in ambient temperature is impaired (I use the term in the scientific sense and attribute no negative sentiment to it).

Why is this temperature regulation problem such a big issue for autistic people? Well, it is another sensory input for us to (attempt to) process. Being too hot includes feelings of skin prickling, sweatiness, fabric sticking to our skin, clothing feeling wet, our skin surface feeling too hot, the tickling sensation of evaporation, active heat from being in sunlight, the brightness of the sun and many more discernible individual stimuli.

Given that autistic people take longer to process some inputs, and are less able to filter or block these individual sensations, it is no wonder that being hot is overwhelming and leads to a loss of functional abilities in other areas as our brain diverts processing energy to dealing with the heat. It can increase the odds of shutdowns and meltdowns exponentially.

In the recent heat I noticed my cognitive abilities took a hit, and my communication skills regressed by decades. I felt that I was at about toddler level of communication in a practical sense – I would not have been able to conduct a conversation. My masking abilities were largely inaccessible and I was much more sensitive to stimuli such as movement, sound and light.

For a further exploration of the effects of dealing with these individual inputs that are part of being too hot, head over to Jen Rose's blog and read about Fork Theory (a corollary to Spoon Theory, which is an analogy for explaining living with a chronic health condition). I love the Fork Theory idea and it is incredibly helpful for understanding how shutdowns and meltdowns can be triggered by what looks like one small thing, but is in fact just one of many individual over-stimulations or demands.

With another hot spell forecast for the end of this week (last full week in August) I will be using my dehydrator on wheels to full effect, while hiding indoors with the curtains and windows closed, and reducing all demands (social, work, practical etc.) until the weather is more agreeable. 

*As a side note, I took my temperature twice a day (at least) for two months or so at the start of the Covid 19 pandemic and found my average baseline temperature to be 36.4°C, a full degree cooler than the average core body temperature. I recorded a low of 34.2°C without hypothermia symptoms (although I will admit I did feel cold). Many morning readings were 35.8°C. As my core temperature is lower than most, my body is trying to defend and maintain a level that is also lower than most.