DOCUMENTARY

BBC1, 9pm One of the things we love about doctor twins Chris and Xand van Tulleken is their willingness to do experiments on their own bodies. Aside from becoming wonderful human demos, it makes their documentaries very entertaining.

This episode is about the everyday miracles that keep the human body alive – to keep our organs working every second, of every hour, of every day.

“We live on a knife edge and we are amazingly good at doing it,” says Chris. Cut to 10-year-old Olivia and her friends who are about to embark on a traditional rite of passage in Norway. As they change into swim suits we notice (with horror, I might add) the small square cut into the thick ice.

Then they jump in – because it’s traditional, and “fun” apparently.

Time for an experiment, and Xand enters a lab to test his body’s ability to maintain its core temperature of 37.5C, as he goes from running in Arctic to Saharan temperatures. A body temperature change of just two degrees either way could have devastating effects.

COMEDY GENIUS Larry David