UNLESS you are made of steel, it is likely that at some time in your life you have been struck down by a bad case of cold or flu or perhaps a viral infection.

Thankfully, for the majority of us, we are over the symptoms within a week or two, whether it’s with the help of drugs or by letting the illness run its course.

But what if the symptoms don’t go away; imagine if the symptoms went on for months or even years; you can’t sleep and every time you attempt to do the simplest tasks, you are left physically and mentally exhausted.

That is day-to-day reality for some of the UK’s estimated 250,000 people struggling to live with myalgic encephalopathy, or ME, as it is better known.

“I’m blessed to have recovered from ME,” said Heather Millard, 31, a PR manager at York Hospital.

“I was diagnosed over ten years ago after struggling to get back to normal health from a string of viral illnesses. “At the time, I was training to be a primary school teacher and the doctor put my constant exhaustion and flu-like symptoms down to post-viral fatigue.”

Despite this, Heather said she knew something wasn’t right and sought a second opinion – eventually being diagnosed with ME.

“On a bad day I couldn’t get out of bed without someone helping me to walk. On a good day I was just shattered and ached all over. Sleeping made me feel more tired but then I was so tired I needed to sleep.

“The worst part was the frustration of not being able to just live a normal life, I felt like an elderly person living in a twenty something’s body.”

Heather is one of the lucky ones and is now a mother to two young girls; she managed to reclaim her life through a steady and determined programme of exercise. She also believes that pregnancy and childbirth helped her recover.

“Despite the sleepless nights and general tiredness that most mums encounter, I started to feel like myself again,” she said. Whatever the reason, Heather has since completed the Great North Run and now considers herself well.

For many of those diagnosed with ME, however, the symptoms can last a lifetime and leave the sufferer confined to their bed or a wheelchair.

Although Christine Wrightson, 64, has not been diagnosed with ME, she suffers from a defect in the pituitary gland, a tiny but important part of the brain responsible for the release of hormones.

She believes her condition may be linked to ME and welcomes the news last month that the Government has pumped £1.5 million into ME research.

Christine, of Huntington, has suffered from profound fatigue since being struck down in 2006, but she has since become a campaigner for recognition of the conditions which she said were often given the catch-all tag of “chronic fatigue syndrome.

“This was the worst fatigue I could ever have imagined,” she said.

“I felt like I was dying. I had nausea and vomiting and terrible weakness all over my body.

“I class myself as having pituitary disease but I had a hell of job getting that on my medical record. It took over three years to get that recognised.”

Christine feels strongly against ME and similar conditions being classed as psychological conditions and she is pleased the £1.5 million in Government cash will be used to focus research on biological causes.

Dr Charles Shepherd, medical advisor to the ME Association, admits that diagnosis can be a long and complicated process and that misdiagnosis does happen.

He said: “Part of the problem with this is that there are a lot of different illnesses which can cause ME-like symptoms.

“When you make a diagnosis you really have to do so through medical examinations. People like myself do see a fair number of people who are misdiagnosed with ME. They may go to their GP and this is a convenient diagnosis.”

Dr Shepherd said sufferers tended to fall in to three groups. There are a minority, like Heather Millard, who, with treatment, are eventually able to live mostly free of symptoms. Then there those who may enjoy periods of progress early on but tend “go up and down”.

He said: “Twenty to 25 per cent are really quite severely affected. They are housebound or wheelchair or bed-bound.

“A lot of the public are confused as to what ME is, just as some of my medical colleagues are confused.”

While a lot of research had already gone in to the condition, the medical world was still not certain what caused ME.

Dr Shepherd said current thinking was that people may be born with a predisposition.

“What seems to trigger it is an acute infection,” he said.

“They get an infection and just don’t seem to get over it. The infection itself goes away but they keep the symptoms.”

In the absence of a dedicated cure, those with ME must listen to their own bodies.

“Providing your management is sensible you can make some degree of recovery,” said Dr Shepherd.

“It’s about self-management and not doing too much or too little.”

Heather Millard agrees. She said: “After I relaxed a bit and stopped fighting against the ME I started to enjoy the benefits of the slower pace of life.

“If I met someone today who had just been diagnosed I would suggest they try to accept it, to never give up hope on getting better and to just take one day at a time. “Setting realistic goals and staying positive helps enormously. Learning to live with ME is an achievement in itself. I’ve such respect and admiration when I read about what some men, women and children go through. “I hope one day we’ll be reading about a cure which will make ME a thing of the past.”