10 April 2014 Last updated at 05:08 GMT

London Marathon 2014: Professor Greg Whyte's marathon top tips

London Marathon

  • Date: Sunday, 13 April

Coverage: Live on BBC One, Red Button, online, mobiles and tablets from 08:30-14:30 BST, plus live text and BBC Radio 5 live commentary. Highlights on BBC Two from 17:30 BST

Fitness expert Professor Greg Whyte offers up some essential advice on running a successful marathon.

He offers some light-hearted advice on warming up, going to the toilet and how much to eat and drink along the way.

Whyte competed in modern pentathlon twice at the Olympic Games and is the man who pushed David Walliams, Eddie Izzard and Davina McCall to their physical limits for Sport Relief.