Body Heat

Back in the 1980s, one of the most heinous crimes a young theatre manager could commit was to miss the final line of the show reports:  WEATHER....?

Another was to allow the on-stage temperature to rise above a level which would result in major West End stars charging into your office brandishing thermometers.

In these windswept Northern isles, the sun is the enemy of any indoor live entertainment; why sit in the dark when there is rare sunshine outside?

And while US cinemas have historically made megabucks when the sun shone, at time of writing London’s West End has yet to fully harness the allure of cool, refreshing air conditioning. 

...mainly because it isn’t easy to adapt a historic (and probably Grade 2 listed) building for the challenges of 21^st century climate change.  Firstly, you need access to air and the plant to chill it; which will probably mean sticking it on the roof.  Then you’ll probably need to hide it behind a piece of wall or masonry contemporaneous with the rest of the building -unless you want a hideous eyesore crowning your beautiful (and protected) building.  Which might mean structural reinforcement.  And then there‘s the noise the plant makes, and…

Of course there is another solution. These old(er) theatres reach peak temperatures during the second show of a two show day, because of the heat from the lamps and the body heat generated by audiences, so just unplug all the lights and keep the public out of the building ..Simples!

Yesterday I woke to the sound of the BBC’s Farming Today telling me that ‘the ideal temperature of a cow is 5°C to 20°C,’ while outside the cat had taken to reclining in the shade of garden furniture (a cat’s ideal range is 22°C to 25C°).

But what about the biped chapters of The Business of Pleasure?

For most indoor activity, the ‘general comfort range’ is apparently 20°C to 24°C, with analytical tasks best suited to the lower range, 20°C and 22°C, and sleep lower still, 16°C to 19°C.

According to a recent paper* there are two systems at work when we attempt to regulate our temperature between these ranges:

 ‘The optimal circadian body core temperature, defined as visceral, blood and brain temperature, for cellular functioning is at 37°C. At body core temperatures of below 0°C cell function is lost due to the freezing of water, whereas above 45°C, enzymes start to denature. As demonstrated by animal experiments, at innocuous temperatures between 15°C and 45°C, thermoceptive neurons located in the skin and in mucous membranes relay to the brain via two pathways: The spinothalamic pathway and the spinoparabrachial pathway.  Signals transmitted via the former pathway terminate in the contralateral dorsal posterior insula to activate behavioural thermoregulation (e.g. seeking warmer/colder environments, adding/removing layers of clothing). Signals relayed via the latter pathway terminate in the preoptic area of the anterior hypothalamus, where they are integrated with thermal signals from the brain, the viscera, and deep somatic tissue to activate autonomic thermoregulation… In humans, this eventually results in cutaneous vasoconstriction and piloerection (goosebumps) to prevent heat loss and brown adipose tissue activation and shivering to generate heat.’ 

And when, hunched forward over our keyboards, and none of the measures above seem to work it may be useful to remember:

‘Cognitive capacity and cognitive control are highly correlated (Engle & Kane, 2003) and the latter has been found to be affected by temperature. Shibasaki, Namba, Oshiro, Kakigi and Nakata, 2017) show that neurobiological inhibition process suffer from heat stress. In decision making, inhibition and executive processes coordinate to achieve an optima solution. As such, the effect of heat on performance can be twofold; not only do higher order complex tasks suffer more than simple automated tasks (Grether, 1973) but wrongful application of an automated process or application of a wrong automated process might also be less likely to be corrected. In other words, even when the direct effect of heat on simple and automated processes is not evident (as stated by Zhang and de Dear, 2017) the outcome can still suffer in quality due to the lack of high order process intervention'*

So check your work once, twice, and ideally get someone else to check …twice.

Cue Jennifer Aniston, 1997: “Here comes the non-science bit… Concentrate!”

I have spent the coldest winters that London could throw at me with my knees inside a gas oven, my typewriter on the hob…

My laptop and I have crossed Andalucía from the Sierras de Córdoba and Jaén to the semi-desert of Tabernas…

But I have never yet needed the temperature to help me f*** up.

DT

28 May, 2026

 *Emerging effects of temperature on human cognition, affect and behaviour Susanne. Fischer, Kathrin Naegeli, Daniela Cardone. Chiara Filippini, Arcangelo Merla, Kay-Uwe Hanusch, Ulrie Ehlert, Biological Psychology 189 (2024)

**Turning up the heat: The impact of indoor temperature on selected cognitive process and the validity of self-report Martijn Stroom, Nils Kok, Martin Strobel and Piet. M. A. Eicholtz, Cambridge University Press, 2023