Health benefits of utility cycling: evidence overlooked
Hagel et al attempt to rebut Dorothy Robinson's evidence that
helmet laws in Australia have had a serious negative effect on public
health, by deterring cycle use whilst failing to improve cyclists’ safety.
In their response, it appears that they do at least accept the evidence
(summarised at ) that laws requiring cyclists to wear helmets do indeed
discourage substantial numbers of people from cycling. However they then
go on to argue this does not necessarily indicate damage to public health,
as it is unclear by how much those people reduce their cycle use, or for
Hagel et al cite a "rule of thumb" (derived from an item of
unpublished personal correspondence) that one needs to cycle for 45
minutes a day, 6 days a week to gain health benefits, and then suggest
that few leisure cyclists are doing this much, implying (presumably) that
the health benefits that we might stand to loose through helmet compulsion
are pretty meagre. Surely though it is not right to refer solely to
“leisure cyclists”, when their own “rule of thumb” suggests that the best
way to gain health benefits is in fact by riding regularly as part of
one’s day-to-day routine – for journeys to work, to school or college, to
the shops? A two-way cycle commute of 20-30 minutes each way is not
unusual, and would easily cover the 1 hour or 40km per week which they
cite as being necessary to reduce CHD risks in 45 to 64 year olds. In any
case, there is other published evidence that cycling for as little as 3km,
3 days a week can still provide benefits.
Given that only 35% of men and 24% of women are meeting the national
recommendations for physical activity, the threat from helmet-
compulsion is not just that it would reduce existing cycle use, but that
it would seriously undermine efforts to encourage more people to cycle
more often. Cycling, together with walking, is one of the few forms of
physical activity (aside from a few minority activities: jogging, inline
skating etc) which can readily be undertaken in the course of ordinary
daily travel. Unlike gym attendance or most "sporting" activities,
cycling does not require any special outlay of either time or money, and
can readily be fitted into ones normal routines. Once adopted, it is a
habit which is easy to maintain. Moreover, cycle use provides the
greatest benefits in other policy areas besides health – e.g. reduced
congestion, air pollution, road danger and greenhouse emissions – when
undertaken not as a leisure activity but as way of reversing the
inexorable growth of unnecessarily car use, especially for short journeys.
A comprehensive literature review of the health benefits of
cycling provides references to many similar findings, several of them
suggesting that there is a “dose-response” relationship between cycle use
and health gains, but that low levels of cycle use are still beneficial.
A key reference however is a population-wide study from Copenhagen which
found that, compared with people who cycled regularly to work, those who
did not do so had a 39% higher mortality rate, regardless of any other
cycling or other physical activity undertaken by those in each group.
This indicates that cycling provides very substantial reductions in all-
cause mortality, which in turn suggests that its health benefits must far
outweigh the risks involved.
That was indeed what the BMA found in its report on Cycling and
Health. Other evidence indicates that those who cycle into middle
adulthood can have a level of fitness equivalent to being 10 years
younger and a life-expectancy 2 years above the average. The
author of the BMA report later estimated that, thanks to these extra life-
years, the health benefits of cycling outweigh the risks by a factor of
When we learn that, two years after helmet laws were introduced,
there was a 43% reduction in cycle use among under 16 year olds in New
South Wales and a 46% reduction among teenagers in Melbourne, it
surely does not take a full epidemiological study to realise that those
teenagers growing up after the law are vastly less likely to cycle in
later life than their predecessors (in any case, I dread to think how one
could isolate the effects of a helmet law in a long time-series study of
the type Hagel et al are suggesting, or what it would cost to conduct it).
What is clear is that we need to find ways to support increased cycle use,
both to encourage children to retain the cycling habit through their
teenage years and into adulthood, and indeed for adults to rediscover
cycling, so that exercise becomes part of their daily norm. Cycle
training is a good way to encourage this, whereas helmet-compulsion
clearly has exactly the opposite effect.
Hagel et al also fail to note that heart disease due to physical
inactivity kills 42,000 people a year, that obesity shortens the lives
of 30,000 people by an average of 9 years per person, and that the
costs of physical inactivity and obesity are £8.2bn and £2.5bn
respectively. The numbers killed while cycling are tiny by comparison
– typically around 130 p.a. in recent years. Even then, it is unknown
how many of these could be prevented by helmet-wearing, however helmets
are only designed for impact speeds equivalent to falling from a
stationary riding position, whereas around 90% of cyclists’ fatal and
serious injuries involve colissions with motor vehicles, making it
very unlikely that helmets could prevent many of the fatal or really
serious injuries which occur, even on the most optimistic assumptions
about their effectiveness. Indeed, we do not know how many of the
cyclists killed are wearing helmets at the time, although media reports
often mention that a helmet was in fact being worn.
In short, helmet laws have the evident potential to shorten hundreds,
if not thousands more lives than they could ever hope to save. Their
effect is not only to reduce existing cycle use but also to deter new
people from becoming regular cycle users. Cycle use for day-to-day travel
is rare – just 1.5% of trips in Britain are cycled. Yet Britain still
has relatively high levels of recreational cycle use – around 9 million
adults (aged over 16) in Britain cycle at least once a year and about half
of them cycle at least once a week. Given concerns not only about
obesity and heart disease, but also congestion, air quality and climate
change, we need to encourage more people to adopt the habit of cycling as
a regular activity, and the large numbers of occasional recreational
cyclists (including children and teenagers) are the obvious “target
group”. We need to achieve rates of cycle use similar to those of
continental neighbours such as Sweden, Germany, Denmark or the Netherlands
(countries which incidentally have much lower helmet-wearing rates, and
better cycle safety – see graph at www.cyclehelmets.org.uk). The vast
majority of Britain’s current adult and child cyclists do not wear
helmets, particularly when riding on minor roads. The last thing we
should be doing is criminalising them any further into car-dependent,
Campaigns & Policy Manager
CTC, the national cyclists’ organisation
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Competing interests: No competing interests