Radcliffe's remarkable admission comes after Denise Van Outen's online spat with former East Ender Natalie Cassidy over jibes about returning to work early as a new mother.
The runner and her new baby are now back home after a traumatic labour in which medical staff had to resuscitate Raphael after the umbilical cord became wrapped around his neck.
Radcliffe said: "I probably had a week completely off.
"I started doing a bit of cross training, walking and pelvic floor exercises, things like that.
"I'm hoping to do some running by Christmas and be back to doing normal training in January."
Cassidy was critical of actress and presenter Van Outen's decision to start working within weeks of having daughter Betsy.
But she was accused of hypocrisy after appearing on-screen with her new daughter Eliza.
Cassidy, who stars in a new E4 show about her path to motherhood, gave an interview recently in which she said: "Denise van Outen went back to work after two weeks because she said she needed to feel normal again.
"I just think, 'What have you had a child for? Having a child should be your job'."
Outraged Van Outen started posting messages on social networking site Twitter after she spotted her critic on ITV's Lorraine show on Thursday.
"Natalie Cassidy criticised me for going back to work after having Betsy. Natalie's on Lorraine show now promoting her reality pregnancy/new mum show. Isn't that work?"
She continued: "She said she did the show for money, so yes, that is work. Pot calling!"
Van Outen was also dismissive of a magazine deal Cassidy struck for her new baby pictures:
"We put our family picture out to raise money for Great Ormond Street, she did a family shot and put the money in her pocket. End of rant."