Measurements are done. Scientists know how my body functions at a pleasant temperature of 21 degrees Celsius. So the fans start working, and the cool breeze gradually lowers the temperature in the room.
“Your brain is tasting your blood as we speak, tasting the temperature, and the brain is now sending signals to the rest of your body,” Professor Bailey tells me.
The goal is to keep my core – my major organs including my heart and liver – at around 37°C.
I was still unaware of the profound changes happening inside my body, but there were already clues from the outside.
By the time the room temperature dropped to 18°C, I was no longer sweating and the hair on my arms had started to stand up to help insulate my body.
“Science tells us that 18 degrees is the tipping point… the body is now working to defend this core temperature,” Professor Bailey shouts to fans launching drones.
Then my fingers turn white and feel cold. The blood vessels in my hands are closed – known as vasoconstriction – in order to keep my blood warm for my vital organs.
This will happen more quickly if you are of a different gender.
“Women tend to feel cold more, because of the hormones (estrogen), and the blood vessels in their hands and feet are more likely to constrict, which makes us feel cold,” says Dr Claire Eglin, from the University of Portsmouth.
The first shiver started at 11.5 degrees Celsius, as my muscles began to vibrate to generate heat.
At 10°C, the fans are turned off. Feeling uncomfortable, but not freezing as we repeated all the body measurements again at a lower temperature it quickly became clear that I was wrong to suspect that 10°C would affect me.
“The body works very hard at 10 degrees,” says Professor Bailey.