Tag: obesity

Cyclists ‘Die in’ at TfL HQ – Blackfriars Rd, London

Cyclists ‘Die in’ at TfL HQ: On Friday evening on 29th November 2013 over a thousand cyclists came to demand safer roads for cyclists and pedestrians across London. 14 cyclists had been killed already that year on London streets, including six in the previous two weeks.

Cyclists 'Die in' at TfL HQ - Blackfriars Rd, London

Cyclists generally get a bad press here in the UK, and proposals and schemes that improve safety for cycling often meet with considerable opposition from non-cyclists, especially where these provide joint use of paths by pedestrians and cyclists.

Of course some cyclists are irresponsible – but so too are many not on bikes, whether driving vehicles or on foot. And we all sometimes do stupid things. Some may ride through red lights – but so do some motorists, and the statistics show that around 95% of pedestrians killed or injured in accidents caused by jumping lights are killed by drivers rather than by cyclists.

Cyclists 'Die in' at TfL HQ - Blackfriars Rd, London

Motorised vehicles – cars, motorbikes, vans, lorries, buses etc are far more dangerous than cyclists because of their higher mass and often much greater speeds which mean that they bring many times more energy to any collision – typically more than 10 times as much, sometimes very much greater.

It’s hardly surprising the of the around 400 pedestrians killed in road traffic accidents each year in the UK on average only 2.5 involve collisions with bicycles – even on those shared pavements you are many, many times more likely to be killed by a collision with a car or other vehicle.

Cyclists 'Die in' at TfL HQ - Blackfriars Rd, London
A cellist played during a long silent vigil

Cyclists are – like pedestrians – vulnerable road users. Unlike drivers in vehicles they are not surrounded by a protective shell of metal, and they have seat belts and air bags which proved extra safety – and its good that they do. But this does all remove them some way from the dangerous reality that all cyclists – however well-behaved and experienced – when sharing road space with them.

Cyclists 'Die in' at TfL HQ - Blackfriars Rd, London

It would not of course be feasible to provide entirely separate street networks for vehicles, cyclists and pedestrians, although it would be good to provide these where possible, and we have made some progress in doing so. But there are many more places where separate ‘dedicated’ cycle paths can and should be provided.

Encouraging cycling has many positives. It reduces the toxic air pollution in our cities – estimated to cause almost 10,000 early deaths in London alone, as well as a great deal of suffering from various lung conditions. And by reducing the number of vehicles on our roads it cuts the congestion on our roads which often brings transport in London to a near standstill (and which is also highly polluting.)

Donnachadh McCarthy announces it was time for the die-in

And cycling provides healthy exercise (which would be even healthier if we cut pollution by having more people on bikes) helping to cut the obesity which, particularly among children, is now a major health problem. It has also been shown to improve mental health.

Cycling is also the cheapest form of transport other than walking, and is often the fastest way to travel in London for relatively short journeys, including some that most of us would find too far to walk.

Worries about safety put many off cycling, as does the weather. But there are relatively few days when our weather makes cycling a real problem (and mudguards help.) Making our roads safer is more of a problem, but doing so would increase the quality of life in the city for all of us. Even drivers breathe the same air and have sometimes to get out of their cars and walk.

Things are happening slowly, but too slow. We are getting more dedicated cycle routes. 20mph zones make streets safer for pedestrians and cyclists, despite the outcry about them in some areas. Improvements in design of lorries to provide all-round vision are slowly coming in…

Protests such at outside the London HQ of TfL on 29 Nov 2013 to protest at the lack of safe road provision that leads to many deaths of cyclists and pedestrians, with a vigil, rally and a 15 minute ‘die-in’ on Blackfriars Road help to raise awareness of the need to improve our road system and encourage TfL to make a positive effort to do so. You can read more about it in my post on My London Diary, which includes the eight demands made by those taking part as well as a description of the event and many more pictures.

Cyclists ‘Die in’ at TfL HQ

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Cycling and health

M3 from Sheep Walk, Shepperton

Every weekday for the past few months I’ve been having breakfast, washing and then getting on my bike for some exercise, riding around ten miles. I take a camera with me and sometimes stop a few times to take pictures which does slow me down a little. I don’t have Lycra and the roads around here are in pretty poor condition, and I sometimes ride on some rough paths, so my progress isn’t that fast, and the rides generally take me 40-50 minutes – an overall speed of 15-12 mph. The pictures here were taken on my rides in the first week of July.

At the start I of these rides was very short of breath, and thankful that this part of South-West Middlesex is extremely flat – one reason for siting Heathrow here. Even now, 4 months after I was ill in March, hills are still a problem if I ride across the river into neighbouring Surrey, though I’m now having to stop and rest fewer times on the way up. But I can now ride up the slopes to cross the motorways or railways without much difficulty.

Cottage, Moor Lane, Yeoveney

At the start the empty roads (apart from the many potholes and cracks) were bliss, but I arrived home exhausted. Now traffic even on the relatively quiet roads I mainly ride is something of a pain but I’ve got fitter and while I’m a little tired when I get home I’m not on my last legs. Cycling has definitely improved my fitness, but I haven’t lost a single pound.

So while I’m pleased that the government is encouraging cycling, and I’m sure it will improve people’s fitness I don’t know that it will actually do much to reduce obesity. Nor am I sure that they are going about getting more people on their bikes in the right way with gimmicks like the repair vouchers and prescriptions. They need to divert much more of the money going into roads into making roads safer so more people feel able to ride on them. As well as providing separate cycle paths where possible this also needs special attention to the edges of roads, the roughly 2m in which cyclists normally ride and which currently are usually in even worse condition than the rest of the roads.

River Thames, Shepperton

It also needs the kind of changes currently being proposed to the Highway Code, which prioritise the needs of the most vulnerable on our roads, pedestrians, then cyclists and then the various other categories of road users. You can contribute to the consultation on this until 11.59pm on 27th October 2020.

I don’t think cycling has a great deal to offer in combating obesity. Cycling is such an efficient process that it uses relatively little energy, and isn’t a very good way to lose weight. Jogging would be better though I find it far too boring.

Lord Knyvett’s Schoolhouse, Stanwell

Obesity is now of course not to do with actually being obese but defined by the WHO for adults as having a BMI of 30 or greater. BMI is a useful but very crude measure, which only takes body mass and height into consideration.

I think I am as fit or fitter than my wife, but in terms of BMI I come out slightly overweight and she appears slightly underweight, a difference of around 9 or 10 in BMI. We eat more or less the same diet and roughly similar quantities. I think the difference in BMI is at least partly if not largely accounted for by the width of our frames. This is reflected in the width across the shoulders – mine being roughly 1.3 times wider., much greater than the 1.09 difference in our heights.

River Colne, Stanwell Moor

The BMI formula, BMI = weight(kg)/height(m)^2 seemed conceptually wrong to the Belgian scientist Quetelet, who first put it forward around 1840, as mass is essentially a three-dimensional property, and so we might expect it to correspond to the third power of height, but that doesn’t give sensible results. The square was adopted for fully grown adults and in order to give roughly acceptable results for the population as a whole, but Quetelet actually pointed out it should not be applied to individuals.

Seven years ago Professor L N Trefethen FRS, Professor of Numerical Analysis, University of Oxford, proposed a revised BMI to make a “better approximation to the actual sizes and shapes of healthy bodies” and it does cut down the difference between Linda and me slightly, bringing her just into the normal range. The differences it makes are rather small, but given the blind reliance we sometimes see on BMI important. Trefethen suggested using instead of the square the power 2.5 of height and points out that Quetelet had found that “during development the squares of the weight at different ages are as the fifth powers of the height” while suggesting the use of the square for fully grown adults. At the time it was certainly much easier to calculate a square, though now calculators and computers make fractional powers easy to use.

Duke of Northumberland’s River and Heathrow

It probably doesn’t matter if we regard BMI as a very rough measure, but does when it comes to setting out charts and and applying them to individuals. If your BMI is 26, you may actually be normal, while if it is 25 you could be overweight whatever the chart says, but it would be too inconvenient to give, for example, a BMI of 26 +/- 3 which would probably be rather more accurate a reflection. It would be more useful for individuals if we could find a more sophisticated formula that gave a clearer indication.

There is of course another equally simplistic but probably more reliable measure that can be applied to individuals to determine obesity. It’s called a tape measure. If you are a man with a waist of over 40 inches (102cm) then you are almost certainly obese.

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