QI: The Book of General Ignorance - the Noticeably Stouter Edition (37 page)

Swim, is the answer your parents would have given, but there’s no evidence that normal swimming after normal eating is risky.

Swimming pools are not particularly dangerous places – according to government statistics you are much more likely to injure yourself taking off a pair of tights, chopping vegetables, walking the dog or pruning the hedge.

And keep well clear of cotton buds, cardboard boxes, vegetables, aromatherapy kits and loofahs. All of these things are becoming more dangerous.

The idea behind the popular injunction against swimming after eating – frequently posted at pools to this day – is that blood will be diverted from other muscles to the stomach, to assist in digesting food, leaving your limbs with insufficient blood, thus leading to paralysing cramps. (In less sophisticated versions, the weight of the food in your gut sinks you.)

Even if you overeat before swimming, the most likely result is a stitch in the side, or a touch of nausea. There is nothing
intrinsically dangerous about the combination of food and water.

A greater risk is dehydration from not drinking, or weakness caused by fasting.

On the other hand, the Royal Society for the Prevention of Accidents (RoSPA) advocates ‘common sense’, arguing that there’s at least a theoretical risk of regurgitation, which might be more dangerous in water than on land.

The 2002 RoSPA report revealed the following causes of accidents for one year in the UK:

Not by sitting too close to one.

Until the late 1960s, cathode-ray-tube television sets emitted extremely low levels of ultraviolet radiation and viewers were advised to sit no nearer than six feet from them.

Children were at greatest risk. Their eyes are so good at accommodating changes in distance that they were able to sit
and watch at a much closer range than most adults.

Almost forty years ago, the Radiation Control for Health & Safety Act compelled all manufacturers to use leaded glass for their cathode-ray tubes, rendering television sets perfectly safe.

The real damage caused by television is the lazy lifestyle it creates. Obesity rates among children in the UK have tripled in the last twenty years, and this has been linked to television. The average UK child aged between three and nine years old spends fourteen hours a week watching television and just over an hour playing sport or doing outdoor activities.

A 2004 study in the journal
Pediatrics
concluded that children who watched two to three hours’ television a day had a 30 per cent higher chance of developing attention deficit disorder (ADD).

In 2005, the research company Nielsen revealed that the average US home tuned in to eight hours of television per day. This is 12.5 per cent higher than ten years ago, and the highest level since television viewing figures were first measured in the 1950s.

The American Academy of Pediatrics estimates that by the time they reach the age of seventy, Americans will have spent an average of eight whole years watching television.

Not much, it seems, and (sadly) not Mummy.

Unlike many creatures, humans don’t ‘imprint’ quickly. While mothers and fathers may form an immediate bond with their baby, it takes most babies between two and three months to show any strong preference for a particular human carer.

Despite the homespun wisdom that says its essential to place a baby with its mother immediately after birth, this is probably more for the mother’s benefit than the baby’s. Research into the development of human attachments at the University of Minnesota in 1999 showed that the bonding process is much slower than most of us assume. It outlined the following steps:

The concept of ‘imprinting’ was made famous by the Austrian animal behaviourist Konrad Lorenz (1903–89), who demonstrated that greylag geese hatched in an incubator would bond with, or ‘imprint’ on, the first moving thing they saw within thirty-six hours of birth (in the original case, it was Lorenz’s Wellington boots).

This fact has been used to great advantage in breeding 
programmes for endangered species of cranes, where their eggs are hatched and reared using hand puppets, humans in crane-costumes and taped calls.

However, there is no evidence that humans imprint in the same way. Indeed a Canadian research team recently found that, up to the age of three months, newborn humans respond almost as positively to the calls of rhesus monkeys as they do to their mother’s sweet nothings.

It is, apparently, dangerous to have eight hours’ sleep a night.

Adults who sleep eight hours a night or more die younger than those who sleep only six to seven hours a night.

A six-year study involving 1.1 million people published by Professor Daniel Kripke at the University of California in 2004 showed that a significantly larger number of people who slept eight or more hours (or less than four hours) a night died during the six-year study.

The average Briton gets between six and seven hours’ sleep a night, which is one and a half hours less every night than our grandparents did. In 1900, a normal night’s sleep was nine hours.

There is evidence to suggest that sleep deprivation leads to short-term loss of IQ, memory and the ability to reason.

Leonardo da Vinci spent almost half his life asleep. Like Einstein, he took short naps during the day, in his case fifteen minutes every four hours. The great lexicographer Dr Johnson rarely got up before noon. The French philosopher Pascal also spent much of his day dozing in bed.

On the other hand, the famously long-lived elephant sleeps for only two hours a day. Koalas sleep for twenty-two hours a
day but only live ten years. Ants, as noted earlier, sleep for only a few minutes a day.

The average person takes seven minutes to fall asleep. Normal healthy sleepers wake up between fifteen and thirty-five times every night.

There are currently eighty-four recognised sleep disorders, including insomnia, excessive snoring, narcolepsy (falling asleep during the day), apnoea (ceasing to breathe while asleep) and restless leg syndrome. The UK has twenty-five sleep clinics, all of which are ‘overwhelmed’ with patients.

Twenty per cent of all UK motorway accidents are caused by drivers falling asleep. The best way to stop this happening is to trap a lock of your hair in the sun-roof.

The second-best way is to eat an apple. This stimulates digestion and provides slow-release energy, which is more effective than the short-term hit of coffee.

According to the World Health Organisation, tobacco is currently the second major cause of death in the world. It is responsible for the death of one in ten adults worldwide, about five million deaths each year, while cancer is currently killing seven million people a year.

If figures continue to rise at current levels, tobacco – and a range of smoking-related diseases – will become the world’s biggest killer by 2030, killing ten million people a year.

Around 1.3 billion people are regular smokers. Half of them – that is 650 million people – will eventually be killed by tobacco.

Developing countries will suffer the most. Eighty-four per cent of smokers currently reside in middle- to low-income countries, where smoking has been steadily on the increase since 1970.

In contrast, smoking levels among men from the United States declined from 55 per cent in the 1950s to 28 per cent in the 1990s. In the Middle East – where half the adult males smoke – tobacco consumption increased 24 per cent between 1990 and 1997.

The economic consequences of smoking in the developing world are just as disastrous as the implications for health. In places like Niger, Vietnam and Bangladesh, impoverished households are spending one third more on tobacco products than on food.

It was not until the late 1940s that modern science linked disease to tobacco and, in the UK, it wasn’t until the Royal College of Physicians report in 1964 that the government fully accepted the link between smoking and cancer. It was another seven years before warnings appeared on cigarette packets.

Despite thirty years of mounting evidence, one in four UK adults (13 million people) continue to smoke regularly (although 70 per cent of those are trying to give up).

In 2004, the Himalayan Kingdom of Bhutan not only banned smoking in public, but also banned tobacco sales, the first country ever to do so.

Depression is the commonest illness treated by doctors in Britain and the fourth commonest illness in the world after pneumonia/bronchitis, diarrhoea and HIV/AIDS (WHO 1999).

It is estimated that up to 10 per cent of women and 3 to 5 per cent of men worldwide suffer from clinical (i.e. severe) depression in any given year.

Approximately 3.2 million people in Britain (7 per cent) are clinically depressed and it’s getting worse. Between 1990 and 2000, the number of prescriptions written for depression every year in the UK rose by more than ten million.

It is estimated that depression costs the UK economy
£
8 billion a year through time off work, treatment costs, suicides and reduced productivity – equivalent to
£
160 a year for every man, woman and child.

This is not just a function of innate British miserabilism or climate: 25 million Americans (9 per cent) are clinically depressed at any one time. In Australia, children as young as five are currently being treated for depression.

In Bangladesh, by far the commonest illness is diarrhoea, followed by intestinal worm infections. But depression is widespread (particularly among women), running at about 3 per cent.

In Africa, depression is the eleventh most common illness, HIV and malaria being first and second. In most developing countries, cultural suspicion of mental illness means diagnosis is difficult and symptoms are more likely to manifest themselves physically than in the West.