To sufferers of the condition, it can be completely disabling, affecting every aspect of life.

Yet myalgic encephalitis (ME) remains largely misunderstood, and is often regarded as psychological.

Last month, Kay Gilderdale of East Sussex was cleared of the attempted murder of her daughter, Lynn, who had ME for 17 years and was left paralysed and unable to swallow.

Kay admitted aiding and abetting Lynn, 31, to take her own life, and was given a 12-month conditional discharge.

Approximately 180,000 people in the UK are affected by ME. Sufferers experience symptoms including persistent tiredness, muscle pain, headaches, sleep disturbance and loss of concentration.

Catherine Berry, of Guiseley, knows the reality of suffering from ME. She was working in the fast-paced world of event management before being struck down with a lethargy she couldn’t understand.

She recalls waking up each morning longing to go back to sleep. “That wasn’t me. I was always up and doing things,” she says.

Catherine went to the doctor who initially put it down to viral fatigue, but her symptoms worsened to the extent where she was constantly exhausted and her muscles ached. She had tests and it was six months before she was diagnosed with ME, aged 27.

“For years I was looking for answers, looking for something that would make a difference, but nothing did. I went on like that for six or seven years,” she says. Then a friend recommended Sue Pemberton, a consultant occupational therapist at Leeds and West Yorkshire Chronic Fatigue Service.

Catherine visited Sue and her team. “I started putting information they gave me into practice and started to feel better,” she says.

“It’s not all plain sailing. There are challenges; sometimes it can be two steps forward and two steps back. You have to try things and see how you get on. It’s about learning to stop before you have to stop.”

She has lived with ME for almost a decade, and with support, she’s now managing her condition which has given her a new lease of life.

Now she’s sharing her experiences with fellow sufferers through Fighting Fatigue, a practical guide to managing the symptoms of ME.

The manual offers advice from health professionals and patients on managing energy in everyday life. The practical, self-help guidance includes assessing energy levels then gradually raising them. It looks at tackling sleep disturbance, overcoming negative feelings and boosting concentration, and explores the effects of ME on family members, and how to deal with this.

The book offers sufferers a strategy to work to, helping them to do things they used to do. Applying the techniques helped Catherine to return to work in a jewellers on a part-time basis.

“Nothing really made a big difference to the way I felt. Living with structured rest and relaxation has enabled her to conserve energy and return to normality. “Using the techniques and strategy has become a way of life,” says Catherine.

Next month she’ll embark on a challenge she never believed possible – trekking to the foot of the world’s highest mountain.

The impetus is her late father, Keith Watmough, who died aged 64, from a heart attack on March 13, 2007. Exactly three years later, Catherine will begin her trek to Everest Base Camp in his memory.

“He was a fantastic, giving man. I wanted to celebrate his life and also my own health, having spent so many years when I never considered that I could do something like this,” says Catherine.

Such a huge trek would challenge even the fittest person.

Now she’s able to face her new challenge – making it to Mount Everest. She has so far raised more than £6,000 for the British Heart Foundation, including sponsorship from Bradford accountants Clough & Company where her late father worked.

Catherine has spent months training, combining walks on Otley Chevin with cardio-vascular exercise. She’s aware that walking in a different climate, and high altitude, will present a whole new challenge. “I don’t know whether it will affect me or not – that is one of the big challenges,” she says.

Fighting Fatigue, published by Hammersmith Press, is available from amazon.co.uk and bookshops. For more information about the book, visit hammersmithpress.co.uk. For more about Catherine’s challenge, visit justigiving.com/catherineeverest.