IELTS Academic Reading Practice Test 392

In 1926 two doctors opened a small centre in a rented house in Peckham, in south-east London, with an ambition that was unusual for its time. George Scott Williamson, a pathologist, and Innes Pearse, a physician, were not attempting to treat disease. They wanted to find out what health actually was. Medicine, they argued, had accumulated enormous knowledge about illness but knew remarkably little about the conditions in which people stay well, and they proposed to study healthy people instead, following them over years rather than weeks.

Their starting point was a conviction that health could not be defined merely as the absence of disease. A person who was not ill was not necessarily well, and the difference mattered. Williamson and Pearse believed that health was something positive, a capacity to live fully and to respond to the demands of ordinary life, and that this capacity depended on a person's circumstances and habits as much as on the state of their body. Doctors, in their view, had been trained to look for what was wrong and were therefore poorly equipped to notice what made people thrive.

The first premises, a converted house, were far too small for the work the pair had in mind, and in 1935 the centre moved into a purpose-built building on St Mary's Road. Its designer was Owen Williams, an engineer whose concrete structures were among the boldest of the period. The building was arranged around a large hall containing a swimming pool, a gymnasium and a dance floor, and much of it was enclosed in glass, so that activity in one part could be seen from another. There was also a nursery where the youngest children could be left. The site was chosen so that families from the surrounding streets could walk to it.

Membership was organised in an unusual way. The centre admitted families rather than individuals: a household joined as a unit, and no adult was accepted unless the children and the other adult in the family joined too. Each family paid a small weekly subscription, deliberately kept low so that the centre would not become a middle-class club. In return, members had the use of the building and its activities throughout the week, and their children could be left in the nursery while the adults swam, danced or simply sat and talked.

The centre's most distinctive practice was the periodic overhaul. On joining, and at regular intervals afterwards, every member underwent a thorough medical examination, including measurements, blood tests and a general physical check. The aim was to detect conditions that had not yet produced symptoms, and to build a detailed picture of each person's state of health rather than merely to record diagnosed illnesses. Families were told the results, and the information was collected into records covering the whole household.

At the same time, the doctors did something that few medical institutions had attempted. They watched. Because the building was open and its members spent their leisure there, the staff could observe how families behaved when nobody was ill: who exercised, who sat apart, how parents and children spoke to one another, which activities people chose. These observations were treated as evidence quite as seriously as the clinical measurements, and the two kinds of record were kept side by side.

The centre's work was interrupted by the Second World War. It closed in 1939 and its activities stopped for the duration of the war. When it reopened in 1946, the mood of the country had changed.

Financial pressure now dominated. The subscriptions had never covered the cost of the medical work, and the centre had always relied on donations and on the enthusiasm of a small staff. Its founders hoped that the new National Health Service, established in 1948, might support an institution devoted to preventing illness. But the service had been designed around the treatment of disease, and it offered no funding for the centre. In 1950 the Pioneer Health Centre closed for good, by which time several hundred families had passed through its doors.

Its influence, however, outlasted it. The idea that health is created by social conditions, by ordinary activity and by the way people live together, rather than delivered by doctors, has become a commonplace of modern public health. So has the notion that prevention deserves money and attention in its own right. Both were central to the work in Peckham long before they entered official policy, and both are now repeated in documents that seldom mention where they came from.

Even the centre's methods have found echoes. Contemporary researchers who try to understand why some communities stay well, and contemporary schemes that prescribe swimming or walking groups for people who are lonely or low in mood, are in a sense continuing an inquiry that began in a small house in south-east London a century ago. The questions those doctors asked, about what keeps a family well and what makes a neighbourhood healthy, are now asked by governments.

The human brain accounts for about two per cent of body weight, yet it consumes roughly a fifth of the oxygen and glucose the body uses. Nothing in physiology is more dependent on a steady supply of fuel, and nothing is more sensitive to interruptions in it. When we exercise, the heart pumps more blood with each beat and the vessels supplying the brain widen, so the organ receives more oxygen and glucose than it does at rest. That much has never been in doubt. What has occupied researchers for the past three decades is the question of whether this extra supply does anything more lasting than keep the brain comfortable while the body works.

The first place to look is the network of small vessels themselves. In experiments with rodents, several weeks of access to a running wheel increases the density of capillaries in the motor cortex and in the hippocampus, the structure most closely associated with memory. Human evidence is necessarily more indirect, but studies using ultrasound and other imaging methods have found that aerobic training improves the ability of blood vessels to widen and contract. Because damage to small vessels is a major contributor to cognitive decline in later life, anything that keeps them healthy is of interest. Exercise also lowers blood pressure and reduces arterial stiffness, both of which protect the vessels on which the brain depends.

The second candidate is a protein called brain-derived neurotrophic factor, or BDNF. Discovered in the 1980s, BDNF supports the survival of neurons and encourages the growth of dendrites and synapses, the connections through which nerve cells communicate. In the 1990s, researchers found that animals given access to running wheels produced more of it in the hippocampus, and the finding gave the field its first plausible mechanism: exercise might create conditions in which the brain can rewire itself. In humans a single session of vigorous exercise produces a temporary rise in BDNF in the blood, although how closely blood levels reflect what is happening inside the brain is still debated.

The most striking human result concerns the hippocampus. In a trial published in 2011, a group of older adults was assigned either to walk briskly for about forty minutes three times a week or to do stretching exercises, and their brains were scanned before and after a year. The walkers' hippocampi grew by roughly two per cent, while those of the stretching group shrank slightly. Two per cent sounds trivial, but the hippocampus loses volume steadily from middle age, and the gain was equivalent to turning back the clock by a year or two. The walkers also did better on a test of spatial memory.

Exercise also changes how the brain feels. The pleasant state that follows prolonged exertion, the so-called runner's high, was long blamed on endorphins, the body's natural opioids. The difficulty is that endorphins are large molecules that cross the blood-brain barrier poorly. Work published in the 2000s pointed instead to endocannabinoids, small lipid molecules that pass easily into the brain and are produced during sustained exercise; when their receptors were blocked in animals, the animals no longer showed the usual signs of post-exercise calm. Exercise also raises levels of noradrenaline, dopamine and serotonin, the messengers that underpin alertness and mood.

Then there is the muscle itself. Far from being a passive machine, skeletal muscle releases a range of proteins when it contracts, and these substances travel in the blood and reach the brain. The best known is irisin, identified in 2012; in mice it appears to influence the browning of fat tissue and may also raise BDNF. Another, cathepsin B, was found in higher concentrations in animals that had exercised, and when its action was blocked the memory improvements disappeared. Lactate, long dismissed as a waste product of hard effort, is taken up by the brain and burned as fuel, and there is evidence that it, too, can stimulate BDNF production. Almost all of this work, however, has been done in mice and rats.

Several large questions remain. The most contentious is whether adult humans grow new neurons at all. Rodents certainly do, and exercise increases the number in the dentate gyrus, part of the hippocampus. Studies of human brain tissue have disagreed, with some finding signs of new neurons throughout life and others finding none after childhood. Equally awkward is the problem of causation. People who exercise are also more likely to sleep well, eat sensibly and avoid smoking, so a correlation between fitness and brain health proves less than it seems; much of the human evidence is correlational rather than experimental. Nor is it clear how much exercise is needed, or whether lifting weights helps as much as walking and cycling.

What can responsibly be said? Official guidelines recommend about 150 minutes of moderate activity a week, a figure derived chiefly from cardiovascular research. Cognitive benefits appear to require similar amounts, and very large doses do not seem to add much. The most encouraging trial for older people is the Finnish FINGER study, published in 2015, in which more than a thousand adults at risk of cognitive decline followed a combined programme of exercise, diet, cognitive training and monitoring of heart health for two years, and declined more slowly than a control group. Because several measures were combined, the contribution of exercise alone cannot be isolated. The reasonable conclusion is that physical activity supports brain health, while claims that any single exercise routine prevents dementia run well ahead of the evidence.

In 2012 the headteacher of a primary school in Stirling, in central Scotland, decided that her pupils were not getting enough exercise and took them outside to run. The arrangement that evolved, known as the Daily Mile, is deliberately simple: about fifteen minutes of walking, jogging or running, outdoors, in school uniform, with no changing and no equipment. It is not a race and it is not a PE lesson. The idea has spread to thousands of schools in many countries, and it has attracted the kind of praise usually reserved for innovations that cost a great deal more. Whether it deserves that praise, and whether it should be compulsory, are separate questions.

The case for the daily run begins with a bleak figure. International guidance recommends that children accumulate at least an hour of moderate-to-vigorous activity every day, and in most wealthy countries fewer than half of them do. Schools cannot fix that on their own, but they are the one institution that sees almost every child, whatever the family's income or the safety of the streets where they live. Fifteen minutes is a small slice of a school day. Because the Daily Mile requires no kit, no changing and no specialist staff, it has spread in schools that had quietly given up on anything more ambitious.

The evidence, however, has not kept pace with the enthusiasm. Studies of the Daily Mile itself are few and mostly small. Several have found that children who take part become measurably fitter over a school year, which is roughly what one would expect, while effects on body weight have been inconsistent. Almost none has followed pupils long enough to show whether a habit formed at the age of seven survives into adolescence, when activity levels typically fall sharply. Nor is it known whether fifteen minutes of gentle jogging demands enough effort to matter for children who are already active. Schools also carry out the run in different ways and for different lengths of time, which makes the studies hard to compare.

The academic claims are weaker still. It is true that a single bout of exercise produces a small and short-lived improvement in attention, and that fitter children on average do slightly better at school. But the second of these findings is hopelessly entangled with income, sleep and parental education. Trials that add exercise to the school day have generally found modest or no effects on examination results. And a quarter of an hour taken from lessons every day adds up: over a school year it removes something like forty-five hours of teaching time, which is not nothing.

There is also the question of who enjoys it. A daily run can be a misery for the unathletic, the overweight, the asthmatic child, or the girl who does not want to be seen sweating in a uniform. Much of the scheme's success in Stirling came from features that are easily lost when it becomes policy: it was not competitive, everyone took part at their own pace, and it was presented as a habit rather than a test. Once a school starts recording times or turning the run into a race, the children who most need to move are the first to be put off. Compulsion can preserve the ritual and destroy the point.

A further danger is substitution. A run in the playground is cheap; a swimming pool, a gymnasium, a specialist PE teacher and a safe space to play at break are not. Schools under financial pressure may reasonably present the Daily Mile as evidence of action on health while cutting the things that would do more good. Something similar happens in policy more widely: a visible daily ritual is easier to announce than a programme to make streets safe enough for children to walk to school, and it photographs better. None of this is an argument against running; it is an argument for honesty about what a run can and cannot do.

That points to the larger issue. Children's activity is shaped by housing, traffic, the price of sports clubs, the distance to a park and whether their parents work shifts. A school cannot compensate for a neighbourhood with nowhere to play, and pretending otherwise shifts responsibility onto teachers and families for a problem they did not create. Governments find it far easier to fund a fifteen-minute slot in the timetable than to redesign the streets around a school. The original scheme was designed as a habit to be enjoyed rather than as a substitute for everything else, and that distinction is easily lost when a local experiment becomes a national programme.

So should schools make every pupil run a mile a day? My answer is a qualified yes, to the daily activity rather than to the mile. A guaranteed period of outdoor movement, at each child's own pace, is a reasonable thing for a school to provide, and its benefits are most likely to be social and behavioural rather than academic: children who move together, outdoors, in ordinary clothes, learn something about what exercise is for. But it should sit alongside decent PE, unbroken playtimes and space to run, not replace them, and it should never be sold as an answer to obesity or to inequality. The habit is worth defending. The arithmetic of the mile is not.