The Queen is as strong as an ox- but do we ask too much of her? A few months ago, she was worrying about Prince Philip after he was taken to hospital with an infection. Yesterday, he was the one doing the worrying as the Queen was admitted as an in-patient for the first time in a decade. For a woman who has shrugged off past ailments as little more than minor inconveniences, her admission seeking treatment for gastroenteritis, however precautionary, came as a profound shock. Her visits to hospitals have generally either been for formal engagements or to check on the welfare of other members of her family. Only once before in recent years has she been rushed to hospital for treatment, and on that occasion - when her groom's horse kicked shingle in her face while riding through the grounds of Windsor Castle - the Queen was back at work later that day. The Queen, pictured last Wednesday, insisted the drive to King Edward VII Hospital was not by ambulance but by private car and that it would not be necessary for anyone to accompany her But yesterday was different. For 48 hours, she had been stricken by a stomach bug that had stubbornly refused to ease. Royal physicians were sufficiently concerned to indicate that her condition could be more effectively monitored in hospital. Even so, the Queen's approach typified that indomitable spirit we are so used to. She wanted no fuss, so the drive to King Edward VII Hospital in central London was not by ambulance but by private car. At the same time, she also insisted it would not be necessary for anyone to accompany her. She would surely know that the presence of a concerned Philip at her side, or an attentive lady-in-waiting, would serve only to cause alarm. In recent years, the bouts of ill-health suffered by Philip have served to take the spotlight away from the Queen But perhaps most significant of all, she first completed an official function at Windsor - presenting a long-service medal to a member of staff - before she would even contemplate the drive to London. Even as arrangements for her admission were being readied at the private hospital in Marylebone, her thoughts were understood to be of the public duties that would have to be cancelled. "She will not have gone to hospital willingly because she loathes making a fuss," says a royal aide. It's not stubbornness, more a recognition that if her plans are changed, so too are so many other people's plans. During the Jubilee celebrations last year Philip and the Queen chose to stand for four hours on a cold, wet June day during the river pageant, such was their devotion to public duty Even as arrangements for her admission were being readied at the private hospital in Marylebone (pictured), her thoughts were understood to be of the public duties that would have to be cancelled In recent years, the bouts of ill-health suffered by Philip have served to take the spotlight away from the Queen. His occasional frailties have made her seem somehow stronger. It is ten years since she was last in hospital, when she had keyhole surgery to remove torn cartilage, probably a consequence of strain to her joints caused by horse-riding. When she emerged from hospital she was on a stick and wearing trousers, a move which deftly hid the effects of the surgery. Earlier that year, she had an operation on her right knee after twisting it while walking on uneven ground at Newmarket. Princes William and Harry, along with the pregnant Duchess of Cambridge, are currently on holiday in Switzerland But these minor procedures apart, the Queen has rarely been troubled by poor health. For many years, she had an annual ECG heart check, which includes a treadmill workout. Each time, she passed with flying colours. A medical source once told me that the Queen's heart was "very sound - the royals all have hearts like bulls." But while she has been blessed with strong health, she has in recent years had to endure Philip's battles with a string of ailments - notably last year when he was struck down by a bladder infection during the Jubilee celebrations. For four hours on a cold, wet June day Philip and the Queen chose to stand during the river pageant. Such was their devotion to public duty that not once did either of these two great-grandparents consider taking the weight off their feet. Indeed, many may today be asking the same question posed after that extraordinary display of quiet physical and moral courage: are we asking too much of the Queen? She shows no sign of slowing up, and the allowances she makes for age are marginal. In purely physical terms, say friends, the Queen is fitter than the Queen Mother was at the same age - and she lived to be 101. In fact, these friends insist she appears to be fitter and possibly even more mobile now than when she entered her 80s. They put this down to a new contentment marking the end of the turbulent and worrying years of family strife, and a new confidence about the future of the monarchy thanks largely to the marriage of Prince William and the former Kate Middleton. She still rides, though a little more gently these days, and wearing a headscarf not a helmet, of course. The Queen appears to be fitter now than when she entered her 80s, perhaps due to a new confidence about the future of the monarchy thanks largely to the marriage of Prince William and the former Kate Middleton Her most painful experience was the deep bite she suffered to her left hand in 1991, which had to be stitched, from one of her corgis. She was trying to separate her dogs from a fight with two of the Queen Mother's pets. To this day she observes a strict regime which has kept her in robust health. She has never smoked and while she likes a tipple - gin and Dubonnet is a favourite - she does not drink to excess, although irritation has been noted when a drink is delayed. As a girl she swam and qualified for several life-saving awards, but she is not thought to have swum in adult life. Walking her dogs and horse riding are her main forms of exercise. In the Seventies, it was suggested the Queen was a follower of WeightWatchers, but the idea of her attending the confessional meetings which are part of that particular regime seems most unlikely. Perhaps above all she is blessed with a phlegmatic cast of mind. During the dark days of the Charles and Diana marriage crisis, she was reported to be taking her corgis out for a walk, bringing them home, washing them and then taking them out again. Philip referred to this as her "dog therapy." But the central factor which sustains her, and ensures she remains in sterling mental and physical health, is her royal duties. Last year, an exceptional 12 months with the Jubilee celebrations, she carried out some 425 engagements, a remarkable statistic for someone who will be 87 in a little over a month. This year there will be fewer, of course, and aides may now gently suggest she scales back even further, but not even a bout of gastroenteritis will slow her down. Long ago, she made it plain that her working life will end not with retirement, but only with death. Her philosophy is simple if, to many these days, a trifle old-fashioned: duty first.