But the image is deceiving. The St. Lazare woman, 21, suffered from fatigue so debilitating that she spent years bedridden. Even today, just taking a shower might be the main activity of her day.

Six years ago, Lidstone was an honour roll student. She played clarinet in the school band, was involved in Girl Guides, belonged to soccer and basketball teams and was passionate about kayaking and horseback riding.

Then everything fell apart.

Because of chronic fatigue syndrome, Lidstone became a prisoner of her bed, 18 hours a day for two years.

Today, having regained a fraction of her energy, she has learned to pace herself for a few activities, but she won't risk a trip to a shopping mall without a wheelchair.

"It's like having no batteries ... like running on empty," explained the slender Lidstone, lounging on the deck overlooking the family garden.

It is a poorly understood and often misdiagnosed disorder whose calling card is severe and chronic exhaustion - at once physical and mental.

Lidstone is among an estimated 341,126 Canadians with the condition, according to a Statistics Canada community health survey conducted in 2003.

The Centres for Disease Control and Prevention in the United States suggests only 20 per cent of the 4 million Americans with the disorder have been properly diagnosed. There's a debate on symptoms, and even the name is controversial.

But it's more than just feeling tired, said Alison Bested, who treats hundreds of affected adult patients at her Toronto office.

"Some people describe the fatigue as so bad it's like having your feet wrapped in wet cement shoes trying to walk though a swamp," Bested said.

While recognized in adults, it was hardly on doctors' radar when Lidstone sought help at age 15. Children were thought not to have fatigue sickness.

In fact, it can strike children as young as 4, Bested said. But many are misdiagnosed as depressed and prescribed anti-depressants, or parents are told to consult a psychologist about school phobias. Lidstone was told to go home and sleep it off.

"One doctor told me to take up swimming," she recounted.

Lidstone's active life changed abruptly one morning when she awoke feeling dizzy. Instead of going to school, she went back to bed. Instead of getting better, she got worse.

Extra-curricular activities fell away. School attendance dropped from half-days to alternate days, from sporadic to not at all, Lidstone said. "I would push myself to do things and then I'd crash."

Apart from debilitating fatigue, the syndrome can leave patients with a cluster of fluctuating symptoms that range in severity, including impaired memory and concentration, chemical sensitivity to perfume and soaps, tender lymph nodes, muscle pain, headaches, dizziness and an irritable bowel.

Lidstone suffered from "brain fog." At her lowest point, she couldn't concentrate long enough to read a paragraph.

Looking after her daughter became a full-time job, Diana Lidstone recounted. But here's the hitch: Patients often don't look ill or have telltale signs of sickness.

"It's not like she broke a leg or had chemo and her hair has fallen out," Diana Lidstone said.

By the time doctors finally ruled out every other illness that causes fatigue - the syndrome is diagnosed by exclusion - Lidstone was spending full days in bed.

No treatment was available.

"At one point, I realized I was grieving for what I thought she was going to be doing all those years," her mother said.

She thought her honour student daughter would experience the usual adolescent things: high school parties and dances and boyfriends, then CEGEP and university.

"I thought, 'I'm going to have to give her a curfew' ... but that wasn't going to happen."

Lidstone's parents tried organic foods and alternative therapies, including daily tai chi.

"We've come to understand that what she does ... will be in a different way. That was a turning point in learning to cope with this," her mother said.

In an attempt to get her child outdoors, Diana Lidstone set aside part of the backyard for gardening. Two years ago, Lauri Lidstone circled the garden plot and promptly went back to bed. Last summer, she helped plant the vegetables herself.

She also kayaked - a few minutes at a time. In the fall, she enrolled in two courses at John Abbott College, but cut back to one.

She gave a talk explaining the syndrome to her classmates and was pleased that it generated questions. "They wanted to know what it is like," she said. So she told them about "the isolation, the loneliness." How, desperate to get her life back, she'd set benchmarks, buoyed by short bursts of energy, only to crash again.

"It's tough losing the hope that magically it will get better," she said.

In the meantime, Lidstone discovered the Slow Movement philosophy and its handbook, In Praise of Slow by Carl Honore, which promotes a stress-free lifestyle with a new approach to time and space.

Lidstone jokes she's almost grateful to her syndrome for leading to an appreciation of living at a different rhythm: "I'm not quite there yet."

ME is difficult to treat but Leo, 13, is learning to take control of his condition. Our correspondent reports

“Do you know, what I hate more than anything else is when someone asks, ‘how are you feeling?’ It’s kind of a rhetorical question, but I don’t feel fine and I hate telling them that because you don’t know how many times I’ve had to say . . .”

This thought, unconcluded and delivered in a croaky and weary voice, forms part of an audio diary that Leo kept throughout much of the time he has suffered from ME (myalgic encephalitis, otherwise known as chronic fatigue syndrome). On Friday parts of the diary can be heard on Radio 4 in Leo, Rusty and ME, which tells the story of his illness through his voice and contributions from his parents (both broadcasters), his sister and the professionals who have helped him. At times it is unbearably poignant to hear the family struggle to endure his deteriorating condition, but it is instructive, too, because ME has long had a bad press.

Five years after the World Health Organisation (WHO) classified it as a neurological disorder, it is still little understood. There is no clinical test to diagnose it, no definitive treatment and no cure. The suspicion that those who claim to have it are malingerers who just need to get a grip persists, yet it is known that it commonly affects high achievers and it is now thought that one in 250 of us will have it at some point. As many as 25,000 children in the UK are thought to suffer from it every year.

Leo became ill in November 2005, a day his mother, Jane Ray – who produces the programme – remembers vividly. He had had a chest infection but seemed to be getting better so the family took him to a Harry Potter movie.

“At the end he looked at me and said, ‘Mum, nothing works, I can’t move’. It was as if dementors had swooped over him and scooped him out.”

Ray does not exaggerate. Over the months that followed Leo’s body ached, he had fearsome headaches and described his tiredness as violent. He found swallowing difficult and lost weight rapidly. Much of the time, he slept. Tests for glandular fever and Lyme Disease at the Whittington Hospital in North London were negative and it was not until January 2006, when Dr Andrew Robins, Leo’s consultant paediatrician, diagnosed a postviral syndrome (this was classed as ME three months later) that the family felt they had reached a turning point. “We knew what we were fighting against and stuff like that,” says the admirably succinct Leo.

His mother is more expansive. “Treating ME is the medical equivalent of watching paint dry,” she says. “The usual NHS view is that there’s nothing they can do to treat it, they just manage the symptoms. But here we had an [NHS]consultant paediatrician who was prepared to say, ‘I will see you every week until he’s better. You won’t be passed from pillar to post, and I will get a team together that will support your care’.

“In a practical way that saved us from wasting thousands and thousands of pounds, as other people have done, on crank cures and snake oil and new therapies that seem to attract people who are bewildered and desperate.”

Robins’s collaborative approach to Leo’s care was designed to support his physical, psychological and emotional needs simultaneously. The team consisted of a nutritionist, a physiotherapist, and Robins’s colleague, Dr Sebastian Kraemer, a consultant psychiatrist. “It was quite clear to me when I first saw Leo that it wasn’t going to be possible to do all this on my own,” says Robins.

“ME isn’t well understood but there seem to be threads of good practice and it seems to make sense to coach the young person with their family and give them a programme where they can be given space to get better over a longer time course than most people would appreciate. There is a problem in certain models in medicine. Instead of working in parallel we think in series and the physician gets to the end of the line and says, I’m sorry, I can’t do any more for you, go and see a psychiatrist. That’s often traumatic for everyone involved because they don’t necessarily feel that there is a psychological issue and feel abandoned by the medical side. We are saying that there are psychological issues and there are physical issues and we’re going to look at them together. In a world of limited resources it’s expensive putting two consultants in the same room for an hour, but it is definitely worth it in certain situations. The work we do for Leo’s family isn’t just me or just Dr Kraemer, it’s the product of the two parts.”

Kraemer remembers meeting Leo and finding a child so tired that it was as though he had been woken in the middle of the night. Realising that Leo is highly imaginative, he suggested that he come up with a name for his symptom. Leo came up with “Rusty” and gave the name to his whole body “because it was like a rusty gate, doesn’t work properly”.

The idea behind the technique is to distance the patient from his symptoms so that he can look at them and think about them separately, Kraemer explains. “If you can look at what’s happening rather than suffer from it you’re more likely to be its master rather than it being your master. It helps people to use mental devices against an unseen enemy, if you like. We’re not claiming that any of this is curative – ME is tiger country – but a lot of children do get better and the objective is to make sure that happens as speedily as possible and not to let anything get in the way – such as wrong kinds of treatment or staying in bed all the time.”

Leo did spend a lot of time in bed and had many remissions and relapses. He lost so much weight that the hospital suggested that he should be fitted with a feeding tube. He didn’t like that idea, started to eat a little more and his weight stabilised. He recorded his wheelchair speeding down a hill and notes drily that when he crashed, his mother was more concerned about the well-being of the recording equipment than her son. Then his friend Curtis told him about a neurolinguistic programming technique called the Lightening Process. Leo was keen to try it, and Robins and Kraemer felt that his enthusiasm meant that the timing was right and that the technique could give him another way of taking control of his condition. As a result of the sessions Leo came up with the image of packing his ME into his wheelchair and abandoning both of them.

“Some of it is positive thinking,” he explains. “Saying I’ve got ME, so it sounds as though I’ve currently got ME, not I always will have. Things like that, really.”

He no longer has a home tutor and has returned to school part-time, and he has started to draw again. His mother finds some of his cartoons to show me. Leo cringes with embarrassment.

We eat the rock cakes he has made, he frets over his hair, but as he gets used to the agony of speaking to a stranger in front of his parents he starts to open up.

His body uncurls, his back straightens, his hands unwind and you begin to see a teenager who no longer looks ill. I admire his sweatshirt.

“The ultimate in cool – being dressed by your mother,” he quips.

“You can do your own shopping now, mate,” she says.

— Leo, Rusty and ME, BBC Radio 4, Friday 11am

Extract from Leo’s audio diary

April 17 2006: “It’s the night before my birthday. I’d like to be excited but I’m not. I’m dreading my birthday to be honest. I thought I’d be feeling better.”

April 18: “It’s my birthday. My stomach woke me up but I went downstairs and flung the door open and it was nice because there were balloons and everything. I opened my cards and then my presents. I got a few very funny cards, good presents. I thought we’d go go-karting but then Rusty had a bit of a bad turn just before, which was inconvenient. I was knackered. We sang Happy Birthday with my birthday cake and then I went to sleep and that was it. I mean, it was good but it was – well, I’m proud of what I did, but I’ve never felt more tired ever.”

"When I did get it I thought, 'OK fine, good. Let's get it over with,'" he said.

"Now they tell me I may never get over it."

There is no vaccine or cure for the two illnesses that can stem from the West Nile virus: West Nile fever or the life-threatening West Nile neuroinvasive disease. At this point, Mark Davis says, doctors don't know which form he has.

Those who come down with the milder, more common West Nile fever usually suffer from flu-like symptoms and fatigue for three to four months. West Nile neuroinvasive disease is an infection of the nervous system that some people develop from the virus. It is a much more serious illness than West Nile fever and can lead to paralysis and death.

For most West Nile fever patients the only way to recover is to rest and wait it out. Almost three years later, the Davises are still waiting.

Mark Davis is thin as a rail and can't put on weight. He worries he may die from the disease.

Dr. Tracy Murphy, state epidemiologist for the Wyoming Department of Health, said the virus affects different people in different ways.

"A significant number of people who had the severe (neruroinvasive) disease, a significant proportion of them can have long term or even permanent disabilities or effects. That number may be up to even 50 percent."

Mark and Janice Davis, who each show varying symptoms of West Nile fever, are unusual in that their illnesses have lasted so long.

"Usually that is seen in the more severe disease (the neuroinvasive form). But even with the less severe West Nile fever illness, people will report lingering fatigue and weakness for several months."

Only one in 150 people infected with West Nile virus ever develop a severe illness. Only about 20 percent of the people infected ever develop mild symptoms.

The rest never become sick at all. The virus cannot be passed from person to person but it is possible to contract it through a blood transfusion.

Mark and Janice Davis contracted the virus while on a fishing trip in northern Colorado in August 2004.

His wife's illness began with a terrible headache about a week after they returned home from the trip. A few days later he woke up in the middle of the night with chills and a fever, and felt so weak he couldn't walk.

"I crawled in and out of the doctor's office," he says. "Literally I was on my hands and knees... We spent the next 10 months so tired you're just sitting there trying to get enough energy to walk 30 feet to go to the bathroom."

The painful headaches still come and go for Janice Davis but for the most part she says she's feeling better. Mark Davis, however, still battles chronic fatigue, muscle weakness, head and body aches, stiffness, irritability and other nagging symptoms that come and go from day to day and week to week.

It's like having the flu and never getting over it.

Some days he feels well enough to go to work down the street at the local fly shop or to take a short fishing or hunting trip. But other days he feels so sick he can't get out of bed.

Doctors seem powerless to help and can't explain why he isn't getting over the illness, he says.

"I feel like it's aged me 10 years."

At university, she added diving and sailing to her list of accomplishments. But within 18 months of graduating in 2001, she was so ill that there were days when she could barely struggle out of bed. Walking was difficult and serious exercise impossible.

"I would wake up feeling really groggy - as if somebody had hit me over the head with a baseball bat - and very depressed, which was really unlike me as I have always been a happy person,' says Lizzie, now 28.

"I knew something was seriously wrong but I had no idea what it was."

Lizzie's GP arranged for her to have some blood tests. When these came back clear, he diagnosed ME by process of elimination, as there is no definitive test for the condition. The symptoms persisted and Lizzie remembers Christmas 2002, one month after her diagnosis, as a low point.

"I could not exercise, go out with my friends or even enjoy a drink without throwing up. I thought this illness would be with me for life."

But by March the following year, Lizzie was on the road to recovery, thanks - she believes - to a technique devised by Manchester osteopath Raymond Perrin.

Perrin - who is not a medical doctor but gained a PhD for his work on ME - believes that the condition is caused by the body's inability to rid itself of harmful organisms and chemicals, including bacteria, viruses and environmental pollutants. He claims that his massage techniques stimulate the lymphatic system - the network of vessels that carry infectionfighting cells round the body and remove foreign bodies - to drain these toxins away.

In one trial, published in the Journal of Medical Engineering And Technology in 1998, the symptoms of 33 patients treated by Perrin improved on average by 40 per cent, while the untreated group deteriorated by an average of 1 per cent.

In a second - unpublished - trial that specifically investigated muscle strength, ME patients who had a year's treatment regained far more strength than those left untreated.

Despite these trials, Perrin's approach remains controversial. It is not accepted by the medical profession and there has been no robust independent research showing that the lymphatic system is involved in ME. His book describing the technique was published last month.

ME - also known as chronic fatigue syndrome - is a debilitating illness that affects up to 250,000 people in the UK, around 55,000 of them so badly that they are housebound. Once labelled 'yuppie flu' and believed to have a psychological cause, it is now more widely recognised as a chronic physical illness, but what lies behind it is still unclear.

A number of possible causes are under investigation. Neil Abbott, director of operations at ME Research UK, says that ME may not even be one syndrome, but instead a collection of symptoms with different causes.

Conventional treatments, including cognitive behavioural therapy (CBT), exercise therapy, painkillers and antidepressants bring relief to some, but others find that they make little difference and turn instead to some of the huge range of complementary therapies apparently offering a promise of improvement.

For of these, including the Lightning Process described in Good Health earlier this year, there is very little scientific evidence.

Lizzie Jolley's doctor prescribed sleeping tablets to improve the quality of her sleep and CBT, both of which helped a little. In February 2003, Lizzie's mother was told about Raymond Perrin by a neighbour whose teenage daughter he had successfully treated for ME. After examining Lizzie, he confirmed the diagnosis.

According to Perrin, ME occurs when the body's nervous system is put under stress, causing the lymphatic system, which it controls, to work less efficiently. The stress may be caused by a physical problem, such as back strain or trauma; by environmental factors such as pollution or by an emotional upset such as a bereavement. In Lizzie's case, he thought that whiplash after a car accident while she was in New Zealand may have been a contributory factor.

Because the drainage pathways of the lymphatic system do not work properly, toxins - including bacteria, viruses, atmospheric pollutants such as cigarette smoke and petrol and waste products from food - build up. One final trigger, usually an infection, increases the toxic overload and tips the patient into the condition known as ME.

On Lizzie's first visit to his clinic in Manchester, Perrin gently massaged her back, neck, armpits and head.

"I remember when he held my skull he was so still that my mum thought he'd gone to sleep. It was as if he was in a trance. I slept the entire way back to Nottingham in the car and then all that night and the following day - about 20 hours, the best sleep I'd had in ages."

After a few weeks, Lizzie began to feel significantly better. First her eyesight began to return to normal, then her concentration improved, the muscles in her legs ached less and her exhaustion subsided.

In May, Lizzie ran a half marathon and this month she is attempting the gruelling Three Peaks Challenge, climbing the three highest mountains on mainland Britain in 24 hours.

"Without a doubt, I have now made a full recovery and I know that I could not have done it without the Perrin Technique," she says.

The Perrin Technique does not work for everybody, cautions Dr Charles Shepherd, medical advisor to the ME Association, who is sceptical about the approach.

"This is just one person's hypothesis and I am not convinced that the theory behind it is scientifically sound," he says.

"The trials that have been done are not of a sufficiently high standard to make people sit up and take notice. Patients may find this kind of treatment helpful when delivered by a sympathetic practitioner, but whether the underlying process actually has any effect on the disease is another matter."

Heather Walker, of the charity Action for ME, said: "As a matter of policy we do not recommend individual therapists."

Last year's Ryder Cup captain returned to action for the first time since mid-May because of post-viral fatigue syndrome Myalgic Encephalomyelitis.

The 49-year-old Welshman had rounds of 69 and 71 for a level par total but was pleased just to be back competing.

"I got tired the last nine. I just collapsed, but I got round," he said.

"My feet are aching, my legs are aching. I'm knackered. But at the Masters I could only walk about 150 yards because I was in spasm.

"I've mostly been playing in a buggy the last couple of months. I'm only 60-70%, but at least I know what it is in. I got a virus in Asia and it took me over the top.

"I've basically got to rest. I've bashed my body for 30 years and I've just got to eat properly, not drink too much - very difficult!

"People have taken 10 to 15 years to get over this, but hopefully I can play every week now."

Woosnam, who has also entered for the European Open and Scottish Open that follow in July, is down to 614th in the world having failed to earn a single penny so far this season.

Sixteen qualifying places for the Open were up for grabs at Sunningdale, but there was little joy for the Welsh contingent.

As well as Woosnam missing out, compatriots Sion Bebb, Jamie Donaldson, Garry Houston, Mark Pilkington, Philip Price, Kyron Sullivan and Gareth Wright all failed.

Pilkington in particular endured a miserable two rounds, ending on 13 over, while Sullivan missed out by a shot after hitting a decent three under par total.