Health and Fitness
1.
Background information.
2. Health benefits associated with regular
physical activity
4. VLDLs, LDLs and HDLs
5. Health-related fitness (HRF)
6. Physiological differences between males and
females
Body
size and composition:
Energy
systems
Strength
Trainability
Exercise
and menstruation
7. Health promotion
1.Background.
It amazing to think that over 100,000 lives are
lost every year in the UK, for failure to apply a medically proven treatment.
Our high-tech health-care system has underplayed and ignored until relatively
recently a simple, low-cost therapy with the capacity to save hundreds of
thousands of lives and millions of pounds. What is more, we have known about it
for thousands of years. The ancient Chinese knew about it. The ancient Greeks
knew about it. In fact, Aristotle, in 300BC wrote that: ‘a man falls into
ill-health as a result of not taking it regularly.’ The Romans not only knew it
— but their physicians
actually prescribed it for health maintenance of their citizens more than 1500
years ago.
So, what is it, this amazing wondercure? It is
simply — physical activity.
The fact that regular exercise is beneficial
for our health and well-being has been known for centuries. Yet, despite our
knowing this, a recent study from the USA states that as many as 250,000 lives
are lost annually due to sedentary lifestyles. Lack of physical activity is now
considered as important a risk for heart disease as smoking, high blood pressure
and high cholesterol. In fact, in developed nations, physical inactivity
contributes to over 30% of deaths from heart attacks. This is made even more
important by the fact that there are far more people who lead inactive
lifestyles than there are those who smoke, or who suffer from high blood
pressure or who have high cholesterol. So, physical inactivity is a huge cause
of premature death and disability.
Historically, we were an energetic nation of
farmers, miners, labourers, merchants and travellers. An active life is one
that almost everyone had to lead before we achieved industrial modernisation,
technological development, the car, television, computers and labour-saving
devices. Today, we have the reputation of being an overweight, lazy, complacent
nation, content to while away the hours with fast food, TV and video games.
The UK National Fitness Survey confirmed what
many health and fitness professionals have known for years — that, as a nation, we are not as fit nor as
active as we should be. As a result of our sedentary lifestyles, we suffer from
a host of illnesses and diseases that affect our quality of life and shorten
our active life span.
The survey found that:
• Those who reported inactive, sedentary
lifestyles generally showed poorer health records (even if they had been very
active in their youth).
• There was a strong association between
those reporting good or very good health status and those participating in
regular physical activity.
• Those who reported participating in
regular physical activity followed generally healthier lifestyles — fewer smokers, lower alcohol consumption,
healthier dietary habits — than
those who were physically inactive.
• Seven out of ten men and eight out of
ten women were taking insufficient regular exercise to achieve a health
benefit.
• Although 80% of the population surveyed
believed themselves to be fit, one-third of men and two-thirds of women were
unable to continue walking at a moderately brisk pace (3mph) up a slight
gradient (1 in 20) without becoming breathless, finding it very demanding and
having to slow down or stop.
• Brisk walking on the level for several
minutes constituted severe exertion for half the women over 55 years of age.
• Whilst activity levels decline sharply
with increasing age, some elderly people were found to be as fit or fitter than
others half their age.
An active lifestyle is, therefore, very
important for our health and well-being. But, how much is enough? And, does it
have to hurt? The answers seem relatively simple:
1. Aim for around 30 minutes of moderate physical
activity every other day. This might include activities such as walking,
gardening, cycling, swimming, dancing, organised keep fit classes and other
recreational activities.
2. The idea of ‘no pain, no gain’ is really not
true, unless you are involved in serious training for competitive sport. Try
activities that will make you slightly breathless —like a brisk half-hour walk. You do not even have to get changed.
For those who currently do not take regular
exercise, begin with a few minutes of daily activity and gradually build up to
30 minutes. Try to build regular physical activity into your life and make it
part of the way you live. Add life to your years — and years to your life.
2.Health benefits associated with regular physical
activity
There is no doubt that regular exercise can
significantly improve health and well-being at all ages. Some of the most
important health benefits, supported by a wealth of scientific evidence
include:
• reduced risk of heart
disease
• better control of blood
pressure
• better control of blood
fats, such as cholesterol
• increased stamina and
reserve capacity to cope with extra physical demands
• increase in bone strength
and mineral content
• prevention of osteoporosis
(‘brittle bone’ disease)
• management of non-insulin
dependent diabetes
• maintenance of muscle
strength and joint flexibility
• maintenance of good
posture
• management of body weight — and, hence, reduced risk of obesity-related
diseases
• alleviation of the effects
of disability
• reduced stress, enhanced
mood and self-esteem.
Many of these benefits will directly affect the
lives of young people. Furthermore, armed with this knowledge and awareness,
young people are also in a position to impart this information to parents and
grandparents. An increasingly active society will have a major impact in
reducing the economic and social costs caused by chronic ill-health or
premature death and improve the quality of life for millions of people.
3.Exercising for effective cholesterol control
Cholesterol is something we have all heard
about. It has been given enormous publicity over the past few years. Too much
is bad for us, it can cause arteries to ‘furr up’ and so lead to heart disease.
This is all true, but does not quite provide the full picture, which is not all
bad news.
Cholesterol is, in fact, essential to our
health and well-being. Without it, our bodies could not function and we could
not even stay alive. Cholesterol is a necessary component of every cell in our
body. It is found in large amounts in brain and nerve tissue; it is a building
block for various hormones, including our sex hormones, testosterone, oestrogen
and progesterone; and it is used to make bile acids, which are a vital part of
digestion.
So, cholesterol is not always bad for us. The
problems occur when we have too much of it floating around our bloodstream.
Then, it really does become a major problem to the health of our hearts, by
‘clogging up’ our arteries.
So, exactly what is cholesterol? Cholesterol is
a fatty substance that the body can either make in the liver, or we can take in
from the food that we eat. Cholesterol and other fatty substances, such as
triglycerides (fatty molecules formed in the liver from the fat eaten or from
other internal sources), are insoluble in water. To imagine what this means,
think of trying to clean a greasy pan without using washing-up liquid — the fat just congeals and floats to the
surface. The body could not possibly cope with clumps of fat floating around,
so cholesterol and triglycerides are dissolved within particles called
lipoproteins, then carried to tissues in the bloodstream. This is a very
efficient system for transporting these essential fatty substances to all the
body cells that need them.
4.VLDLs, LDLs and HDLs
There are three major types of lipoprotein:
1. Very Low
Density Lipoprotein (VLDL): VLDLs transport mainly
triglycerides from the liver to body tissues. Eating a lot of saturated fats usually means the body is likely to have
lots of VLDLs floating around in the bloodstream. High triglyceride levels are
known to be an important risk factor in heart disease.
2. Low
Density Lipoprotein (LDL): LDLs are the main method for transporting
cholesterol to the tissues. If the diet is high in cholesterol, the liver will
manufacture more LDLs to handle it — and LDL levels are likely to be high. So, LDLs are often termed ‘the
baddies’ — and high LDL levels
are a major risk factor in heart disease.
3. High
Density Lipoprotein (HDL): HDLs are the ‘garbage collectors’, picking up
unused cholesterol in the blood and transporting it back to the liver for
dismantling and converting into bile acids, to help the digestive processes.
Some of the cholesterol is then passed out in stools, thus providing an
important method for the excretion of unwanted cholesterol. This is why HDLs
are often termed ‘the goodies’. A high level of HDLs is now thought to be very
important for heart health.
When cholesterol is checked, a single value, between
four and six (the units are in millimoles per litre of blood), is normally
given. The ideal value is around 5.2mmIl. This is a measure of total
cholesterol (TC). Basically, this is the total of LDLs and HDLs. However, what
this does not tell us is how much of this total is ‘bad’ LDL and how much is
‘good’ HDL. Current research now tells us that whilst high TC levels are not
good for cardiovascular health, a perhaps more important factor in preventing
heart disease may be the need for high HDL levels. Many doctors now consider
the ratio of LDL/IIDL or TC/HDL as better predictors of heart disease risk than
TC on its own.
Additionally, a low level of triglycerides
(TGs) is also highly desirable for coronary prevention.
Most certainly, diet can help control blood
lipids (fats) and this is one good reason why low fat, high fibre eating plans
are now routinely recommended. However; exercise also has a very important part
to play in controlling both cholesterol and triglycerides.
Many studies have shown that regular aerobic
exercise will elevate HDL levels considerably In fact, most researchers
consider exercise as a more powerful factor than diet in raising HDL levels.
Studies at University College Chester noted a 35% increase in HDLs in a group
of sedentary ladies who undertook an eight-week course of moderately vigorous
low-impact aerobics. Women tend to have a naturally higher HDL level than men,
so the potential for improving HDL levels amongst males is significant. This is
now thought to be one of the most significant reasons for the dramatic drop in
coronary risk amongst active males.
Lifestyle
factors that increase HDL levels — in approximate order of
importance:
1. Aerobic exercise — at least 90 minutes a week
2. Weight control
3. Not smoking
4. Moderate alcohol
consumption
Significant changes in triglyceride levels have
been shown by many researchers. One recent North American study reported a fall
of 43% in triglyceride levels amongst a group of sedentary men and women who
were asked to engage in aerobic exercise, such as brisk walking, for around 30
minutes, 3—4 times a week. The body uses the triglycerides as a fuel for
aerobic exercise — so exercise is a
great way to lower triglyceride levels.
Total cholesterol and LDL levels are also shown
to be lower in active people, largely due to their generally healthier
lifestyle, such as having good eating habits, not smoking and moderate alcohol
consumption. Controlling blood fat levels is a key feature in improving heart
health. A combination of low fat, high fibre healthy-eating habits and taking
regular aerobic physical activity are powerful ways of exercising this
cholesterol control.
5.Health-related fitness (HRF)
Health-related fitness is the ability to carry
out daily tasks with vigour and alertness and with energy to spare in case of
sudden, unexpected demands. A good level of health-related fitness is strongly
related to a low risk of illness and disease. Cardiorespiratory fitness,
muscular strength and endurance, flexibility and optimal body composition are
all important and measurable components of health-related fitness.
Many of these factors will influence general
health and well-being. For example, a good level of strength is important for
the everyday tasks of lifting, carrying, pulling and pushing. Being supple will
help keep joints in good working order and help prevent aches, pains and
injuries. A good level of stamina requires strong lungs, a healthy heart, clear
blood vessels and well-toned muscles. Too much fat means the body will be
operating less efficiently, so maintaining the correct weight is also
important. Whilst agility, speed, co-ordination and balance are generally
considered to be skill-related components of physical fitness, improving these
aspects of fitness will also benefit us in day-to-day activities and lead to
more ‘body confidence’. For example, we may have to run for a bus or chase up a
flight of stairs, so speed off the mark is important. Good posture, balance and
co-ordination may help prevent injury and help us to perform daily tasks more
efficiently. Good levels of strength are important for gymnastics, whereas
stamina will assume greater significance in games or athletics and suppleness
will feature more strongly in dance.
Whatever a person’s age, promoting optimal
health involves reaching and keeping a good level of physical fitness. Leading
an active lifestyle not only improves health — it is also great fun.
Note: When promoting health-related fitness to
students and evaluating this fitness, you should bear in mind the physiological
differences between males and females, which may affect physical performance.
6.Physiological differences between males and females
Body size and composition:
Compared with the average adult male, the
average adult female:
• is 7.5—10cm (three to four
inches) shorter
• is 11—14 kgs (25—3Olbs)
lighter in total body weight
• carries 4.5—7kgs
(10—lSlbs) more body fat
• has 18—20.Skgs (40—451bs) less
muscle and bone weight.
The performances of women are closer to males
in swimming than in running. In water, greater body fat creates less drag and
more buoyancy and, therefore, less energy expenditure is needed — about 20% less energy per kg of body weight.
In running, the extra body fat of the female is
a burden to performance.
Children: body
size differences are minimal in prepubescent children, as are performances in,
for example, running and swimming.
Energy systems
Anaerobic
capacities of the adult female are less than the adult
male — largely due to smaller muscle
mass. Although concentrations of ATP and PC are approximately the same in male
and female muscles, females tend to have lower maximum lactate levels —largely due to the smaller muscle mass of
females. The greatest discrepancy in swimming and running times between males
and females occurs in those events which take 1—4 minutes, i.e. 400—1500m
running, 100—400m swimming.
Aerobic capacity (max
V02) — litres/mm — is 15—25% less in adult females than in adult
males (but the difference is much smaller when body weight is taken into
account).
Haemoglobin, heart
size and blood volume are around 25—30% lower in untrained females compared to untrained males
(but only 12—20% when both are trained). Lung volumes in the average female are
around 10% less than in the average male.
Strength
The
influence of testosterone is the major factor in the average male being around
30% stronger than the average female.
Strength
differences between average adult males and females are least pronounced in the
legs and most pronounced in the arms and shoulders.
The
muscles of the average male are approximately 15% longer and 40% thicker than
in the average female.
Maximum
male strength occurs in the mid-20s; at 40 male strength is 95% of maximum; and
at 60 it is around 80% of maximum. Female strength declines much more quickly.
At 50, the average female has 50% of the strength of the average male.
Trainability
Relative strength gains in females are the same
or even better than in males when following similar weight training programmes.
Strength training programmes for females do not
cause excessive muscular bulk (muscular hypertrophy is regulated mainly by
testosterone, which is ten times higher in the average male).
Comparable physiological and biochemical
changes leading to greater physical working capacity can be produced in both
males and females following similar training programmes.
In some ultradistance events, women approach
and often overtake male performances.
Exercise and menstruation
Mild exercise does not promote menstrual
disorders but very heavy, intensive training can induce amenorrhea (cessation
of menstruation) in some females.
Female sportspeople should be allowed to train
and compete during menstruation —provided
that they know that no unpleasant symptoms will occur and that their
performances will not be greatly affected.
For
most females, performance will be unaffected during menstruation, however,
there is wide individual variation. Endurance sportspeople report greatest
susceptibility and variability.
Dysmenorrhea
(painful menstruation) is less common in women who are physically active than
in those who are not.
7.Health promotion
Whilst young children are usually spontaneously
active and delight in physical activity and play, unfortunately, many have
adopted habits of inactivity by their early teens. Large-scale surveys of young
people’s activity patterns have been carried out in many countries, including
Canada, USA, Belgium, Finland, Sweden, Norway, Czechoslovakia, Poland,
Netherlands, Austria, Spain, Australia, New Zealand and the UK. All these
studies tend to reveal similar findings — namely, that significant numbers of young people lead sedentary
lifestyles with a distinct lack of regular, vigorous physical activity.
Additionally, boys tend to be more active than girls, particularly in older
children and adolescents.
A British study of 500 secondary-school
children showed that two-thirds undertook no vigorous exercise outside school
hours, and ongoing studies show similar findings. Moreover, it has been found
that the average British young person spends about three hours a day watching
television. It is not just in Britain where we see this problem, most
industrialised countries have highlighted similar problems with their youth.
Canadian studies have consistently shown poor
levels of fitness and sedentary lifestyles in many children — one study reported that over 40% of young
people watch more than 15 hours of television per week and only 20% take any
form of regular physical activity. Similar results were found in Australia and
New Zealand, and European studies show comparable trends. An excellent review
of physical activity patterns in children and young adults is contained in
Armstrong and Welsman (1997).
Promoting active lifestyles must start in
childhood, so that students become aware, at an early age, of the importance of
physical fitness to their future health and well-being. Knowledgeable young
people, equipped with skills to enhance their health and help prevent illness,
are invaluable to society. It is important that our children retain a delight
in being active and that the habit of exercising is continued through
adolescence and into adult life. Exercise needs to be promoted in both
educational and recreational settings, in the family and in the community, in
order to foster positive attitudes to physical activity for a lifetime.
Health promotion is clearly multi-dimensional,
involving a cross-curricular approach with healthy life skills being taught and
discussed within a range of subject areas. It is also multi-sectoral, in that
it does not lie purely in the domain of the classroom but within the context of
the total school and college environment and the policy of the institution
towards issues such as healthy eating and not smoking. In other words, the
school or college has a major role in providing a ‘health-promoting
environment’ — not just for
students, but also for the whole school community.
PE has, for a number of years, been a key area
for the development and encouragement of health-related skills. Through the
teaching of physical activities, the development of ‘body confidence’ can be
linked to other behaviour patterns such as eating, smoking, alcohol, drugs and
sexual matters, which clearly impact on the lives of our young people. Positive
attitudes towards healthy and active lifestyles can be fostered by the example
of ‘doing’ it rather than merely ‘talking’ about it.