The 62-year-old chat show host revealed his daughter Betsy, 31, cannot walk very far due to her illness and has been using an electric wheelchair.
Those with fibromyalgia suffer with widespread musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues. Betsy also suffers from chronic fatigue syndrome and postural tachycardia syndrome (POTS) which causes an abnormal increase in theheart rate after sitting or standing.
Speaking on 'Loose Women', Jonathan said: "She has fibromyalgia and she has chronic fatigue syndrome and POTS syndrome as well, which is where your heart rate shoots up.
"We found a good… there's a thing called the Perrin treatment. The guy who invented it, he came to talk to me about it and she looked it up online because she's a smart young woman, so she has to want to do the treatment.
"You know, I mean, I can't just say to her "try this, try that" if she thinks it's wrong in some way and if she's not going to enter it one hundred per cent, of course it's not worth doing.
"But we've been having that treatment going on and she's definitely showing some improvement."
Jonathan - who also has daughters Honey, 25, and Harvey, 28, with his wife Jane Goldman - added: "She still can't walk very far. We got her an electric wheelchair in the summer, so we can at least go out and go for walks with the dogs and that's lifted her spirits a lot. "Because that's the problem, if anyone out there who knows or who's got someone with a long term illness, you know, it's the depression. Being stuck indoors and not being able to join in with things because even stairs are a challenge to her.
"So if we're going out we have to give her plenty of time to get ready, get downstairs and then have a rest before we go to the next step, you know. "It does have an impact but the good news is she's definitely showing improvement and feeling better in herself. So we're relieved and we're happy with that."
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