The star's progress was followed on the official Sport Relief Twitter feed. Shortly after she began the challenge, it said: "Seventh fall - seven miles done. Cold, hard, slog."
Messages of support for the presenter were posted on The One Show's website.
Eddie Cheever said: "You are crazy and amazing all at the same time."
And David Anthony called her "an inspiration".
Epic bike ride
Footage of her challenge will be shown on The One Show at 1900 GMT on Friday.
Lawrence Dallaglio is hoping to raise �1 million
A whole host of stars have been taking part in sporting challenges for the fundraising event.
Former England rugby captain Lawrence Dallaglio has just completed an epic bike ride which saw him cycle across all of rugby's Six Nations.
The 37-year-old, who is hoping to raise £1 million, said it was "fantastic to have reached the finish line" in Edinburgh.
"Everybody who has taken part deserves a beer tonight to celebrate," he added.
He was joined along the way with fellow sport stars Andrew Flintoff, Michael Vaughan and Will Greenwood.
Dallaglio set off from Rome in the snow in February and reached Murrayfield stadium on Friday, in time to see Scotland and England fight it out at the weekend for the Calcutta Cup.
Earlier this month David Walliams, Fearne Cotton and Davina McCall completed their own 1,000 mile bike ride, which began in John O'Groats in Scotland and ended in Land's End in Cornwall.
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