Cold weather: What does an unheated room do to your body?

The measurements are made. Scientists know how my body functions at a pleasant temperature of 21°C. The fans then turn on and a cool breeze gradually lowers the temperature in the room.

“Your brain is tasting your blood as we speak and it’s 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 heart – that is, my major organs, including my heart and liver – at around 37°C.

I didn’t yet know the profound changes happening inside my body, but there were already clues outside.

By the time the room temperature dropped to 18°C, I was no longer sweating and the hairs on my arms were starting 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 that core temperature,” Professor Bailey shouts to the buzzing fans.

Then my fingers turn white and they feel cold. The blood vessels in my hands are closed – this is called vasoconstriction – to keep my blood warm to my critical organs.

This would happen even more quickly if I were a different gender.

“Women tend to feel cold more, because of the hormones (estrogen), their blood vessels in their hands and feet are more likely to constrict… and that makes us feel cold,” says Dr Clare Eglin of the University of Portsmouth.

My first shiver comes at 11.5°C as my muscles begin to tremble to generate heat.

At 10°C, the fans turn off. I feel uncomfortable, but I’m not freezing because we repeated all the body measurements at a lower temperature and it quickly became clear that I was wrong to doubt that 10°C would affect me.

“The body works very hard at 10 degrees,” says Professor Bailey.