Temperatures have reached more than 38C (100F) during the ride

But her husband Mike said the 42-year-old Leeds mother of three was "extremely unwell" and had come close to abandoning the charity ride.

He said it was "only will power" which had kept her going on Friday, but the journey had been helped by better weather conditions.

Mrs Tomlinson is now aiming to reach New York by 1 September.

She plans to stop immediately if that does not happen.

'Tense night'

Mr Tomlinson said: "Jane went to bed on Thursday without knowing whether we would be starting Friday's ride.

"She was extremely unwell and we had two alternatives; either to bring forward Monday's rest day or abandon. It was a tense night which in turn made resting more difficult, which exacerbates the problem she has.

"Friday morning it was only will power that got her up with the thought she'd cycle the first few miles and see how she was.

"Knowing that you've got up, ticked off some miles and New York is a little nearer put the physiological balance back to Jane and despite being unwell the ride is positive."

Earlier this month Mrs Tomlinson said she would never have contemplated her latest challenge if she had realised how unwell she would be.