Clare Balding walks a section of the West Highland Way, north from Balmaha, with twin sisters Pauline Walker and Fiona Rennie.
Pauline and Fiona are both 'ultra runners' and they haven't, before, walked the West Highland Way. However they have run the entire route, non-stop, several times. It's one of their favourite challenges on the ultra-runner calendar; running through the night, dealing with hallucinations, and pushing themselves to the limit is all part of the experience.
Clare hears about their adventures, their close and supportive relationship, and Fiona's recent battle with mouth cancer as they slow to an unfamiliar pace to enjoy the beautiful scenery north of Balmaha.
Producer: Karen Gregor.