A Review of Pedalling Health
Pedalling Health (British spelling) is an Australian web site with excellent information about cycling health. I felt that its design might discourage the more casual reader, so I decided to provide questions and answers about the site,
following the same order as the original except when another order seems
to be demanded. Then my readers can check the original to read more exact
information, to find the sources, and to look at the excellent charts.
Q: What is Pedalling
A: Pedalling Health
is an investigation into medical and other research on the value of exercise,
particularly walking and cycling.
Q: What sources
were used in their paper?
A: The authors
have carefully documented authoritive sources for every medical
statement; check their web site to find these sources. In talking
about traffic solutions, other sources and/or their own opinions are used.
Q: Who are the
authors and what is their background?
A: They are four
Australians: Ian Roberts is a Lecturer in science at the University of
Adelaide, Secretary of the Bicycle Federation of Australia, and a member
of the South Australia State Bicycle Committee; Harry Owen is an Associate
Professor in Anaesthesia and Intensive Care at Flinders University; Peter
Lumb is a Lecturer in Social Work and Public Policy at the University of
South Australia and also Vice President of the Bicycle Institute of South
Australia; Colin MacDougall is a Lecturer in the Department of Public Health
at Flinders University.
Q: Why are cycling
and walking stressed over other exercises?
A: The authors
state that exercise needs to be "moderate, habitual, and not seasonal."
They conclude that the only activities that fully meet this definition
are gardening, walking, and cycling. However, they do not discuss the health
aspects of gardening or compare it to the other two. In addition they point
out that cycling (and walking) could help environmentally and economically.
That is, cycling to work, to school, to run errands, and to visit friends
could reduce the use and expense of motor vehicles. They also point out
that sports activities or "packaged' exercises that are often advocated
for exercise actually involve greater risks. And people are more likely
Cycling and walking, on the other hand, involve little expenditure
for equipment or fees, serve useful daily purposes, are practical for people
with various fitness levels - including the least fit, and are attractive
to people who don't normally exercise. Special bicycles are even available
for those with severe physical handicaps.
Q: What is meant
by moderate exercise?
A: This paper shows
that exercising at 70% of maximum heart rate is better than exercising
at 60%, but says that 2,000 kCal of exercise per week is more important
that a few sessions of breathless and sweaty exercise. The most appropriate
level of exercise has not been determined.
Q: Other exercises
involve greater risks than cycling?
A: Here are the
comparative risks of hospital injury for popular sports:
/ 100 hours
Q: Did you
say that people who are engaged in sports are more likely to quit?
A: Yes, Pedalling
Health doesn't give figures, but says that exercise declines with age,
both for the population as a whole and for individuals. Cyclists show a
smaller decline than those involved in sports. Lapsed athletes may have
a greater risk than the non-sport population. Girls in particular are likely
to drop out of exercise activities while in their teenage years, and inactive
children become inactive adults. A non-sport exercise such as walking or
cycling allows everyone to participate all year round. In particular, walking
or cycling to work or school is an habitual, daily activity that should
lead to good health. Cycling is also an activity that older people can
safely engage in without the risks of more strenuous exercises.
Q: Does it really
matter if people get enough exercise and how much does it matter?
A: Looking at the
risk of heart disease alone, for men, being sedentary is equivalent to
smoking 20 cigarettes a day, having a systolic pressure over 150 mm Hg,
or having a blood cholesterol level over 6.9 mmol/L. A sedentary lifestyle
also fosters coronary heart disease (CHD), stroke, obesity, and type II
diabetes. CHD is the leading cause of death in Australia and has the highest
medical costs as well.
Q: What are the
benefits of cycling?
A: Cycling on a
Q: How much exercise
reduces the cholesterol levels in the blood.
increases the high density lipo-protein/cholesterol ratio in the blood
reduces the chances of strokes and heart attacks caused by clotting.
reduces the chances of illnesses caused by high blood pressure.
is as effective as drugs in reducing high blood pressure.
makes obesity unlikely thus helping reduce the chances of diabetes.
A: The benefits
of regular exercise begins at 800 kCal of exercise a week, but 2,000 kCal
is preferred; that is, from
two and a half to six hours of exercise a week for the average
Q: What are the
benefits of more exercise?
longer has some measurable benefits as well. Exercising more than 2,000
kCal a week led to a 2/3rds
reduction in the number of heart attack deaths. The risk of
death by heart attack is reduced by 20% by 2,000 kCal of exercise, but
6,000 kCal of exercise will reduce it by over 50%. Beyond that, the benefits
level off. (6,000 kCal would be about 18 hours per week of cycling for
a touring or commuting cyclist.)
Q: If exercise
is healthy, why don't people do it more?
A: Two quick reasons
are the amount of time spent watching TV and the amount of time spent in
motor vehicles, since people only have so much time. When asked why they
didn't exercise more, people in Australia gave these three most common
answers: no time 33%, no confidence 23%, and no desire 13%. Some of the
reasons for these answers might be people's fears of highly competitive
sports or activities and their fear of injury during training. Also, they
might find many of the exercise activities promoted to be unnatural to
them. High-intensity exercises can require more skill and will that many
people have, especially older people and sick people. The chances of injury
are greater as well. High-intensity exercises can also cause cardiovascular
disease problems. Unfortunately, exercise and fitness are now being marketed
as products for those whose health is already in decline. Preventive exercise
is much more important.
Q: Is there any
correlation between fitness and longevity?
A: One third of
all deaths due to coronary heart disease, colon cancer and diabetes are
caused by physical inactivity.
Q: Isn't this kind
of chart just showing that those who are naturally the healthiest will
live the longest?
|Fitness and Death
A Strong Negative Association
all causes per 100,000 years
||level of fitness
A: The risk of
a sedentary lifestyle and the benefits of exercise are independent of 1)
high blood pressure, 2) unhealthy lipid ratios in the blood, and 3) being
overweight, so exercise benefits everyone.
Q: Well, don't
most people get enough exercise anyway?
A: In Australia,
27% of people are sedentary
28% engage in weak exercise (less than 800 kCal or 2 1/2 hours of exercise)
25% get moderate exercise (more than 800 kCal, less than 2,000 - 2 1/2
to 6 hours)
20% get optimum exercise (more than 2,000 kCal or 6 hours of exercise)
In all, it can be said that about half of the people of Australia are
inactive enough to significantly increase their chances of illness.
Q: But is exercise
that important to one's overall health?
A: These are the
greatest causes of death in the USA:
A combination of all causes 34%
A sedentary lifestyle 33%
Chronic disease 16%
Tobacco and alcohol 8%
High blood pressure and overweight 7%
Family history 2%
Q: Do cycling and
walking have proven benefits when performed as simple transportation rather
than as exercises?
A: One study compared
men who happened to walk or cycle with those who were inactive and found
that the walkers and cyclists with at least 1,000 kCal a week of expenditure
had only 42% of the coronary heart disease of the inactive.
Q: Why is cycling
a better exercise than walking?
A: Walking provides
less exercise for the heart. In a Finnish study of men and women who had
freely chosen their own method of exercise, walkers reached 60% of their
maximum heart rate, and cyclists reached 70% of theirs. As a result, the
cyclists' bodies improved more: the walkers averaged a VO2 max
of 38 while the cyclists averaged 57. The cyclists exercise was high enough
to achieve a training response; that of the walkers was not. The cyclists
therefore achieved better health benefits from their exercise.
In a controlled study to check these results, which lasted ten weeks,
in which one group walked and one group bicycled, the cyclists showed an
improvement of 7.3% in VO2 max while the walkers showed an improvement
of 1.6%. On the treadmill test, the cyclists improved 13% and the walkers
9%, even though the cyclists had started at a higher level.
Q: What is the
effect of exercise on specific health problems?
A: For better blood
lipid and lipo-protein profiles:
One needs at least 1,000 kCal of exercise a week (2-4 hours)
Benefits accrue up to 4,500 kCal a week (10-20 hours)
Exercise and diet have over twice the benefit of diet change alone.
For lower blood pressure:
In four weeks, systolic blood pressure of 97 dropped to 88 with three
sessions a week and 84 with seven sessions a week. Here are the effects
of exercise on blood pressure in men:
For type II diabetes, those with high-risk are helped as follows:
less than 500 kCal, 47 deaths per 10,000 years
less than 2,000 kCal, 35 deaths per 10,000 years
more than 2,000 kCal, 27 deaths per 10,000 years
For osteoporosis, physical activity has been shown to increase bone
density, while inactivity decreases it.
Q: We've looked
at the benefits. What are the problems caused by cycling and walking?
A: First, it must
be recognized that all forms of prevention and treatment have costs and
side effects. For example, drugs that treat coronary heart disease are
known to also cause depression and sudden death. Because exercise prevents
the problem before it occurs, the costs are much lower. However, exercise
can lead to injury.
A study made in Australia looked at hospital injuries and compared
the time involved in activities to the number of injuries. The results
showed that football is 38 times, squash is 26 times, basketball is 22
times, and soccer is 12 times as dangerous as cycling per hour.
It needs to be pointed out that most cycling injuries are minor.
Only .5% of cycling injuries are critical as opposed to 3% of pedestrian
injuries. Cycling injuries are less serious than those of other road users.
However, 90% of all substantual cycling injuries are from collisions with motor
Q: Would you say,
then, that motor vehicles are the real problem?
A: It cannot be
denied that our preoccupation with the safety of motor vehicle users has
been at the expense of cyclists. Automobiles, in particular, create three
threats: 1. they are dangerous to their occupants, 2. they threaten other
road users, and 3. they encourage a sedentary life.
The policy of designing automobiles and roads to be safe for motor
vehicle users alone tends to make cycling more dangerous.
Q: Is the risk
of motor vehicle collisions equal for everyone?
A: No, the data
shows wide variations according to the age and sex of the cyclist, the
type of road being traveled on, and the age and sex of the motor vehicle
operator. In particular, teenage cyclists and arterial roads show a much
higher rate of accidents. For those over 18, the chart shows arterial roads
as having accident rates above 150 per million hours and well below 50
for non-arterial roads. For teens, the accident rate is about 450 per million
hours on arterial roads. In the 1991 Australian data, at all age groups,
accidents to males outnumber those to females by two or three to one (however,
no attempt was made to compare the number of hours of riding or the number
of riders between the two sexes). The greatest number of deaths from the
same survey is among male children and teens. However, other data shows
that males in Australia spend four times as much time cycling as do females,
and teenage males do 40% of all cycling.
Q: Are there benefits
to other road users from cycling and walking?
A: Walking and
cycling are "non-polluting, non-congesting, non-road damaging, non-threatening,
health promoting, and environmentally sustainable."
Q: Which is the
greater risk to a cyclist, getting killed while cycling or dying from coronary
A: For Australian
cyclists on the road six hours per week, there is a reduction in risk from
heart disease of 85 deaths per 100,000 years and an increase in deaths
from cycling of 19 per 100,000 years. Nonetheless, they still have a death
rate of 121 per 100,000 years from CHD. There are additional health benefits
to cycling as well, which lack exact figures, but they also help reduce
the death rate of cyclists at the same time. So, the benefits of cycling
greatly outweigh the risks.
Q: What is the
single most effective method for decreasing bicycle deaths?
A: When asked this
question, Peter Croft, Manager of the Road Environmental Safety, Roads
and Traffic Authority of New South Wales identified lowering motor vehicle
speeds as the answer. Lowering speed limits would have two results: 1.
It would give more time in which to avoid the accident. 2. It would reduce
the speed of impact.
Impact speeds in a collision with a motor vehicle largely determine
if a cyclist will live or die. Looking at collisions between motor vehicles
and pedestrians, at impact speeds below 20 mph, only a tiny
number of pedestrians are killed; at impact speeds greater than 30 mph, only
about 5% survive. Speed also affects the ability to stop. Between 25 and
50 mph, the distance required to stop triples from 60 feet to 180 feet.
Thus accidents are more likely to happen at higher speeds.
One Australian study estimates that pedestrian fatalities would drop
by 60% if maximum traffic speeds were reduced by 12 mph (20kph).
I strongly recommend reading Pedalling Health or at least looking at
the excellent charts. It is now available from two sources (see the right column for the url's).