Absolute Adrenalin. This week, Tomorrow's World investigates the secret of physical endurance. Two teams compete for five days in an adventure challenge involving running 300 miles, swimming lochs, scrambling across gorges and abseiling down a rock face. Can science explain how they manage this feat? Presented by Katie Knapman. Producer Sian Griffiths ; Editor Saul Nasse
Repeated next Wednesday with sign language (S) (W) FURTHER INFORMATION: Ceefax page 623; Website: www.bbc.co.uk/tw