成人快手

From bungee jumping to cycle couriers, presenter Justin Rowlatt encounters the businesses that run on an adrenaline rush.

Endocrinologist Maralyn Druce explains how we are pre-programmed for fight or flight when we receive a nasty shock, while David Kirke - pioneer bungee jumper and founding member of the Dangerous Sports Club - retells the many ways he sought to trigger his own adrenal glands, all in the name of art.

Plus, Justin takes a heart-pumping spin through the London traffic on a bike with no gears or brakes, desperately trying to keep up with courier Akos "Kaos" Kis.

Producer: Laurence Knight

(Picture: Bungee jumper; Credit: melis82/Getty Images)