Davina Mccall – famous for her fitness levels and workout DVDs – is struggling with day one of her Sports Relief challenge, suffering from early stages of hypothermia.

Writing on Twitter, the official Sport Relief page wrote: "#Davina's had to take an unscheduled stop. So cold and battling the winds has made her body tense, muscle fatigue is setting in."

Davina McCallAll the gear and no idea - only kidding Davina

"In temps of just 3 degrees with a bitter windchill the medics say #Davina is showing early signs of hypothermia." "She's made it to the lunch stop. They were the worst conditions we've had on any challenge we've ever done," they said.

Davina took to her account over her lunch break and wrote: "I'm in tatters... That's the hardest thing ive ever done. 50 mph winds... Freezing rain/hail .. It's biblical."

The trip started at Edinburgh Castle yesterday morning and finishes in London on Friday. The challenge includes cycling, swimming the freezing Lake Windermere, scaling the colossal Scafell Pike on foot and running a full marathon, all to raise money for Sport Relief.

“Before a mile has been run, cycled or (and I can barely even write it without blubbing) before I've gone near any 'open water', I've learned a great deal about myself,” wrote Davina in an article for The Independent. “Firstly I have literally cried every single day in the build up to this challenge. Not necessarily in pain, but more out of an odd mix of foreboding, guilt and pressure,” she added.

“I'm the first woman in the history of Sport Relief to lead a challenge. I know this sounds odd, but as a woman I really, really don't want to be the first woman not to complete a challenge.”