Eating to win: activity, diet and weight control
E112_3
Eating to win: activity, diet and
weight control
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Eating to win: activity, diet and weight control
About this free course
This free course is an adapted extract from the Open University
course E112 Introduction to sport, fitness and management:
www.open.ac.uk/courses/modules/e112.
This version of the content may include video, images and
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You can experience this free course as it was originally designed
on OpenLearn, the home of free learning from The Open
University - www.open.edu/openlearn/health-sportspsychology/health/sport-and-fitness/eating-win-activity-diet-and-weightcontrol/content-section-0.
There you’ll also be able to track your progress via your activity
record, which you can use to demonstrate your learning.
Copyright © 2016 The Open University
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Eating to win: activity, diet and weight control
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Eating to win: activity, diet and weight control
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Eating to win: activity, diet and weight control
Contents

Introduction

Learning outcomes

1 Activity, diet and weight control

2 Activity versus dieting


2.1 Activity and appetite

2.2 Post-meal lipidaemia

2.3 How much food and how often?
3 Fitness and fat metabolism

3.1 Eating and drinking for performance; before, during
and after exercise

3.2 Role of high GI foods for athletes

4 Diet, exercise and cholesterol

5 Hydration: Water and sports drinks

6 Eating disorders and the female athlete triad

Conclusion

Keep on learning

References

Acknowledgements
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Eating to win: activity, diet and weight control
Introduction
In this free course, Eating to win: Activity, diet and weight control, we
will examine the links between physical activity and weight
management as well as considering the importance of adequate
pre-and post-exercise nutrition and hydration.
In examining the role of physical activity in weight management,
we will compare physical activity and dieting as weight loss
methods and discuss the relative benefits of physical activity, such
as an improved blood lipid profile and increased lean tissue.
What we eat before and after exercise can have a significant effect
on sport and exercise performance, therefore the course will also
consider pre and post exercise nutrition and hydration for optimal
performance.
Finally, the course will consider disordered eating and what is
known as the ‘female athlete triad'.
This OpenLearn course is an adapted extract from the Open
University course E112 Introduction to sport, fitness and management.
This OpenLearn course provides a sample of level 1 study in Sport
[http://www.open.ac.uk/courses/find/sport].
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Eating to win: activity, diet and weight control
Learning outcomes
After studying this course, you should be able to:

recognise the importance of physical activity in weight
management

compare and contrast physical activity and dieting as
methods of weight loss

understand the importance of pre and post exercise
nutrition and hydration

describe the ‘female athlete triad'.
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Eating to win: activity, diet and weight control
1 Activity, diet and weight control
This course will focus on why dieting alone is not a successful
strategy for weight control. There is a clear relationship between
physical activity and measures of body composition such as waist
to hip ratio, waist circumference and body fat. Yet data from the
Health Survey for England shows that in 2004 only one-third of
men and one-quarter of women were taking thirty minutes of
exercise at least five times a week (NHS, 2006). Low levels of
physical activity are associated with poor diet and obesity, which
may in turn be a barrier to being active (Skidmore, 2007).
According to NHS statistics (NHS, 2006) the main reasons given
by adults for not participating in active sports during the last year
were: their health wasn’t good enough (50 per cent), followed by
difficulty in finding time (18 per cent) and not being interested (15
per cent). In this course we will consider why this inactivity is of
concern in relation to healthy weight and why physical activity is a
key component for weight loss and weight maintenance.
Physical activity influences appetite and leads to improved overall
fitness levels. In turn, higher fitness levels mean you gain
advantages that benefit your weight control, because of the
increased use of body fat as an energy source, without losing lean
muscle mass. One of the major physiological advantages of
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Eating to win: activity, diet and weight control
exercise is that levels of fat in the blood are reduced. We will
consider how exercise can influence cholesterol in the blood, and
therefore reduce the risk of coronary heart disease (CHD).
Reading 1 Activity and weight control
Allow about 1 hour 10 minutes
Now read the extract linked below from ‘Fitness and Health’, by
Sharkey and Gaskill. In this reading you will learn more about the
influence of exercise on weight control compared with dieting.
Right-click on the following link to open the PDF in a new tab or
window.
View document
View discussion - Reading 1 Activity and weight control
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How much energy is used during activity is related to several
factors including the duration and intensity of the exercise. For
effective weight control, Sharkey and Gaskill recommend
moderate rather than high intensity exercise, because more
calories are used before exhaustion is reached. Others emphasise
that intensity alone is not so important, and it is the total energy
expenditure (duration and intensity) that is more relevant. Sharkey
and Gaskill also emphasise that greater fitness allows more
activity and therefore more weight control, hence frequency may
be more important than intensity. Exercise may be more effective
than dieting because of the excess post-exercise oxygen
consumption (EPOC), where calorie expenditure remains high for
a short while after the period of exercise (the recovery period).
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Eating to win: activity, diet and weight control
2 Activity versus dieting
In Reading 1, Sharkey and Gaskill refer to several studies that point
towards the need to include physical activity in weight-control
programmes for successful longer-term outcomes. This is because
restricting calorie intake alone, by dieting, leads to a loss of lean
tissue (muscle mass) and body water in addition to fat. They
emphasise that when the body loses lean tissue it becomes less
able to burn calories due to the decreased metabolic rate, and so
when energy intake increases again, fat is regained more easily
than prior to the calorie-restricted diet. Weight loss with exercise
allows the decline in body fat levels without the accompanying loss
of lean tissue. Indeed, exercise will increase lean tissue and thus
increase basal metabolic rate (BMR). Sharkey and Gaskill
conclude that exercise and dieting combined is more effective than
dieting alone.
2.1 Activity and appetite
As physical activity and food intake are the two key components in
energy balance, exercise may have an influence on food intake.
Effects on intake are likely to be influenced by the duration,
intensity and frequency of exercise. Appetite is a complex
phenomenon and is influenced by several factors. In the brain,
within a region called the hypothalamus, is the control centre for
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food intake, the appestat. Many psychological factors influence the
desire to eat. Physiological factors, such as blood sugar levels and
hormones, also influence the appestat. It is argued that regular
exercise helps the appestat to adjust calorie intake to energy
expenditure.
It is likely that the types of nutrients in post-exercise food can
influence the effectiveness of weight control. In a study on the
effects of exercise on energy balance, Tremblay et al. (1994)
provided free access to diets of varying fat content to individuals
after a 60-minute running session which induced a 500 calorie
energy deficit. They found that when exercise was combined with
free access to a high-fat diet, individuals were in positive energy
balance (750 calories) whereas when exercise was combined with
medium- or low-fat diets, individuals were in negative energy
balance (-500 and -1000 calories respectively). This suggests that
for the exercise to be of benefit in weight loss then high-fat foods
must be avoided. Exercise does not provide us with permission to
eat high-fat foods; there is a trade-off between the calorie loss
from the physical activity and the calorie intake from the foods
consumed.
2.2 Post-meal lipidaemia
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Lipidaemia (or lipaemia, the presence of fat in the blood) is
associated with atherosclerosis. Studies have shown that exercise
either just before or after a meal is effective in reducing lipidaemia,
by increasing fat utilisation. Sharkey and Gaskill state that exercise
before eating may inhibit the appetite and increase fat metabolism,
since the metabolic rate remains high immediately after exercise,
and that a post-meal walk or other physical activity is also able to
reduce lipidaemia. Because metabolism remains high after
exercise, this may be the best time to eat a meal if weight loss is
the goal.
2.3 How much food and how often?
Sharkey and Gaskill point out that by eating food over several
periods in the day (three to six), that is, little and often instead of
eating a couple of larger meals, the blood lipid and cholesterol
levels will be lowered, since the metabolism of the fat eaten will
occur over a longer period. In contrast, avoiding meals will lower
the metabolic rate and so blood lipid and cholesterol levels will
increase.
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3 Fitness and fat metabolism
Reading 2 Fitness and fat
Allow about 30 minutes
Read the extract from ‘Fitness and Health’ by Sharkey and Gaskill
linked below. In this reading you will discover the benefits of
physical activity on fat mobilisation and utilisation.
Right-click on the following link to open the PDF in a new tab or
window.
View document
View discussion - Reading 2 Fitness and fat
Fitness contributes to energy expenditure and weight control. As
fitness improves it is possible to do more work at the same heart
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rate and level of perceived exertion; you are able to burn more
energy for the same perceived effort.
The term metabolism means the breakdown of foods to release
energy. We can metabolise fat, carbohydrate or protein to release
energy.
3.1 Eating and drinking for
performance; before, during and after
exercise
During exercise, fatigue may be caused by depletion of muscle
glycogen stores and low blood sugar levels. In overall terms, a
low-fat diet with plentiful, low GI (glycaemic index) carbohydrates
and a suitable amount of protein and plenty of vitamins and
minerals is most suitable for athletes. Hydration is also very
important and it is considered later in this course. To prepare for
exercise, high-carbohydrate meals and snacks are needed to
maximise stores. The pre-exercise meal should be taken around
two hours before exercise and should consist of low to moderate
GI carbohydrates with small amounts of protein and some vitamins
and minerals, for example, a chicken salad sandwich made with
wholemeal bread. Both immediately before and during exercise
which lasts for more than one hour, carbohydrate foods with a high
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GI value will delay the time before muscle glycogen stores become
depleted.
The important aspect of post-exercise recovery is the replacement
of carbohydrate. Depending on the intensity of exercise, 7 to 12
grams per kilogram of body weight per day of carbohydrate are
required. Evidence suggests that higher GI snack foods may also
be more appropriate immediately after exercise since they promote
glycogen storage. Glycogen storage occurs faster in the first two
hours after exercise but does not begin until after 1 gram per
kilogram of body weight has been consumed (Burke, 2007).
Therefore it is very important to refuel quickly, using a suitable
snack, when there is limited time between training sessions. One
example of a high GI snack providing 75 grams of carbohydrate
would be a plain bagel (90 grams) with two heaped teaspoons of
jam (Bean, 2006) and this snack would begin the refuelling
process. This should be followed by a carbohydrate-based main
meal. It is important to begin training sessions in a fully hydrated
state and it is crucial to re-hydrate during and after exercise to aid
a speedy recovery. It may take several hours to fully hydrate even
after a loss of only 2 per cent of body weight due to physical
exertion. Since alcohol is a diuretic agent and will interfere with
rapid hydration, as well as interfering with recovery, the choice of
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post-exercise drinks should be carefully considered. Alcohol
should be avoided for at least three hours.
3.2 Role of high GI foods for athletes
Foods with a high GI value have a useful role in the diet of athletes
since they can be helpful in the speedy replacement of muscle
glycogen stores. Table 1 shows examples of some high, moderate
and low GI foods.
Table 1 Examples of high, moderate and low glycaemic index
foods
High GI
Moderate GI
Low GI
Glucose 100
Cornflakes 81
Potato (boiled) 56
Parsnips 97
Chips 75
Sweet potato 54
French baguette 95
Bagel 72
Bananas 52
Lucozade Original 95 Watermelon 72
White pasta 50
Honey 87
Wholemeal bread 71 Muesli 49
Potato (baked) 85
White bread 70
Porridge oats 49
Sports drinks 70
Baked beans 48
Weetabix 66
Apples 38
White rice 64
Yogurt 36
Shredded Wheat 64
Chickpeas 28
Raisins 64
Whole milk 27
Cherries 22
Fructose 20
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(Source: Adapted from Bean, 2006)
A summary of the key information about the use of the glycaemic
index for physically active people is presented below:

High GI foods are useful two to three hours before and
during exercise and in recovery (within two hours of
exercise) to speed up glucose entry into muscle cells
and to replenish the glycogen stores quickly.
Glycogen is replaced at its fastest rate within two
hours of exercise.

After exercising, glycogen stores need to be topped up
quickly to be ready for the next training session. A
high-carbohydrate diet with high GI foods immediately
after training will result in greater glycogen storage.
The term ‘bonking’ is used to describe the experience
when cyclists become fatigued as blood glucose
levels fall too low, although you may perhaps be more
familiar with the term ‘hitting the wall’, often used to
describe the same experience in long-distance
running. Food or drinks containing high amounts of
carbohydrate are the best choices for initial postexercise snacks to replenish muscle glycogen stores
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in order to meet the demands of the next training
session.
Assessing the effectiveness of your eating
strategy
Allow about 50 minutes
Keep a record of everything you eat and drink and all of the
physical activity you undertake over a period of 2 or 3 days.
Examine the times and frequency of your meals and drinks, and
comment on their size. Also note the times and frequency of your
bouts of exercise. How does your pattern of eating and drinking
compare with the timings that would be most appropriate for
exercise performance? Did you eat a high-carbohydrate snack
within two hours of exercising? Judging the food record ‘by eye’,
was your overall diet high in complex carbohydrate and low in fat?
View discussion - Assessing the effectiveness of your eating strategy
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4 Diet, exercise and cholesterol
Cholesterol is another type of lipid that is often given bad press
due to its role in developing CHD. However, it is produced and
used by the body for a range of functions. In fact, cholesterol is so
important that it is produced by the liver to meet our daily needs.
However, if we consume foods containing cholesterol our liver will
make less to compensate for this. The problem comes when we
consume more than is needed to meet the requirements of the
body.
Cholesterol performs the following functions:

helps to form the structure of the cell membranes

produces bile, which aids fat digestion

produces steroid hormones such as oestrogen and
testosterone

produces vitamin D from sunlight.
Cholesterol is found in the same places as saturated fats. Meat,
poultry, egg yolks, seafood and dairy products are all sources of
cholesterol.
Reading 3 Blood lipids
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Allow about 30 minutes
Read the extract from Fitness and Health by Sharkey and Gaskill
linked below. There are quite complex issues about the
biochemistry of blood lipids (triglycerides) and cholesterol
mentioned here. The important thing to remember is that
cholesterol in blood is not all of the same type and so health
professionals use measurements of HDL and LDL in addition to
overall cholesterol concentration for a more accurate indication of
the risk of heart disease.
Right-click on the following link to open the PDF in a new tab or
window.
View document
View discussion - Reading 3 Blood lipids
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Figure 1 The function of the liver in processing cholesterol
Table 2. Risk of coronary heart disease with increasing blood
cholesterol levels
Blood cholesterol level (mmol/l) <5.2 5.2–6.5
Risk of CHD
6.5–7.5
>7.5
Low Increased Moderate High
Blood cholesterol level is measured in millimoles per litre (mmol/l),
and this can be measured through a simple blood test. There is
cause for concern if the measure of blood cholesterol is over 5.2
millimoles per litre. However, it is important to know the ratio of
LDLs to HDLs as well: it should be 75 per cent LDL to 25 per cent
HDL. If the amount of LDL is more than 75 per cent, then there is
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also an increased risk of CHD. It is possible to have a low blood
cholesterol level but still be in danger if the HDL count is less than
25 per cent.
HDL count is increased by taking regular exercise and is lowered
by smoking and increasing exposure to pollution. LDL count is
raised through excess alcohol intake and high consumption of
foods rich in saturated fat.
The key points about blood triglyceride and cholesterol are:

Elevated blood levels of cholesterol and triglyceride
are associated with increased risk of CHD.

Dieting and exercise can both reduce blood plasma
triglyceride levels.

Exercise enhances the removal of triglyceride from the
circulation, and its utilisation in the muscle cells.

The major cholesterol-carrying proteins are LDL and
HDL.

LDL particles in the blood contain a high concentration
of cholesterol. LDL is a major factor in the
development of CHD since these LDL particles
contribute to the narrowing and hardening of the
coronary arteries.
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
When considering blood cholesterol level
measurements, the lipid profile is very important.
There is a direct relationship between LDL and CHD
whereas there is an inverse relationship between HDL
and CHD, so that as HDL levels increase the risk of
CHD is reduced. Exercise helps to shift the balance
between these, raising HDL and lowering LDL. Thus
regular physical activity provides a very substantial
health benefit.
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5 Hydration: Water and sports drinks
It is essential for health that good levels of hydration are
maintained. Water is the most important aspect of our diet
because we can’t manage without daily supplies, and fluid losses
must be replaced quickly to avoid long-term damage, for example,
to the brain and vital organs. The body only has a small reserve of
water, and dehydration of tissues results in weakness, headaches,
tiredness and loss of concentration, followed by collapse and
eventually death. Water losses through urine, from the skin, from
breath and in faeces average about two litres per day, and they
must be replaced. During physical activity dehydration results from
sweating, and so rehydration is necessary to maintain physical and
mental performance levels. It is important not to rely on your thirst
as an indicator of dehydration, because by then it is already too
late as the effects of dehydration are already impacting on
performance. Even a loss of water representing 1 to 2 per cent of
your body weight can result in a lack of concentration and loss of
performance.
Video content is not available in this format.
Video 1 Hydration
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Source: The Open University, 2008
Figure 2 It is important to maintain hydration levels during exercise.
View description - Figure 2 It is important to maintain hydration levels
during exercise.
Figure 3 illustrates the damage caused by increasing levels of
dehydration on the body. It is necessary to drink plenty of fluids
before, during and after exercise, especially in warm weather. As a
general rule, you are advised to drink about 0.5 litres (500
millilitres) about two hours before exercise and 150 millilitres every
ten to fifteen minutes during exercise. For events of a long
duration, hypotonic or isotonic sports drinks, which supply some
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carbohydrate, may be preferred to water. These sports drinks also
contain the electrolytes, sodium and potassium, which control the
flow of water in and out of cells and are vital to ensure absorption.
Figure 3 Adverse effects of dehydration on work capacity (Greenleaf, 1992).
View description - Figure 3 Adverse effects of dehydration on work
capacity (Greenleaf, 1992).
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Water is an excellent sports drink and may well be the preferred
drink for activities of less than one hour, but isotonic sports drinks
are considered beneficial for use by athletes for events of one hour
or more duration. Isotonic drinks are so-called because they have
the same number of particles per 100 millilitres as plasma and
therefore are quickly absorbed. They contain 4 to 8 grams of
carbohydrate per 100 millilitres and some electrolytes (including
sodium) that aid absorption. Isotonic drinks are absorbed as fast,
or faster, than water alone. These drinks are beneficial for
endurance sports because they provide a source of fuel (usually
glucose sucrose, glucose polymer or maltodextrin) in addition to
water to reduce dehydration. Colouring and flavouring are usually
added. You may have come across other sports drinks that are
described as hypotonic or hypertonic. The decision to use these
drinks will depend upon whether the goal is promoting hydration or
promoting carbohydrate uptake from the gut. Hypertonic drinks
contain more than 8 grams of carbohydrate per 100 millilitres.
They increase the amount of carbohydrate fuel that can be
supplied to the muscles, but that will also decrease the rate at
which water is available because it slows the rate at which the
contents of the stomach empty into the small intestine. When the
provision of water for fluid replacement is the first priority, then
hypotonic drinks (less than 4 grams of carbohydrate per 100
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millilitres) or isotonic drinks should be used, not hypertonic drinks
(Figure 4).
Figure 4 The energy concentration of different types of sports drink.
View description - Figure 4 The energy concentration of different types
of sports drink.
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6 Eating disorders and the female
athlete triad
Disordered eating describes a range of abnormal eating practices,
but the most common among women who engage in physical
activity are anorexia nervosa and anorexia bulimia. Disordered
eating is more common among female athletes than in the general
population and it is more common in sports such as gymnastics
where a low body weight is desirable. Male athletes with eating
disorders are less common, but cases are observed among
jockeys, boxers and wrestlers.
Sources of support include b-eat (formerly the Eating Disorders
Association). For guidelines in dealing with eating disorders you
can visit the b-eat website.The organisation offers advice and
information sheets that can be downloaded from its website, for
athletes, coaches, and family and friends who may be concerned
about the problem.
Female athletes who have inappropriate low-energy diets and
demanding exercise regimes are at risk of developing the female
athlete triad syndrome.
The triad is associated with increased morbidity and mortality and
is a syndrome of three interrelated conditions:
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
disordered eating

amenorrhoea (absence of periods)

osteoporosis (loss of bone density).
These three conditions have a synergistic effect (i.e. the overall
effect is greater than the sum of the three individual conditions).
Disordered eating increases the risk of muscle and tendon injury
and decreases concentration. In addition, low body-fat levels may
result in menstrual dysfunction including amenorrhoea, which is
also more prevalent among female athletes than other women.
Amenorrhoea athletica may be a consequence of a combination of
factors such as an intense training regime with a strict weightcontrol diet that is too low in fat. Amenorrhoea is associated with
low body fat and an associated lack of oestrogen that influences
bone density. When hormone levels drop, the breakdown of old
bone exceeds the formation of new bone and the result is a loss of
bone minerals and bone density. This is a problem that affects
young women (less than twenty years old), because at this time
they should in fact be accumulating bone to achieve a healthy
peak bone mass. Young adults with low bone density do not catch
up bone density over time, and if a high peak bone mass is not
achieved by the time they reach their mid-twenties it is not likely to
be achieved at all. Bone density falls below the fracture threshold
at a younger age in people with a low peak bone mass. Therefore
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amenorrhoea leads to poor bone health and the increased risk of
stress fractures, and early osteoporosis as bone density declines.
Bone loss can occur quickly in young female athletes who have
stopped having periods and treatment should not be delayed.
Teenage girls who recover from anorexia nervosa and
amenorrhoea continue to show thin spinal bone years after
oestrogen levels have returned to normal (Goulding, 2007).
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Eating to win: activity, diet and weight control
Conclusion
In this course the discussion centred on why it is particularly
important to use physical activity in combination with dieting as a
means of achieving and maintaining a healthy weight, since
activity ensures that fat loss is achieved without the loss of lean
tissue. You learned the following:

Physical activity should be included in weight loss
programmes as it minimises losses of lean body mass
(muscle, etc.).

Physical activity leads to a decrease in blood levels of
triglycerides and LDL and an increase in HDL.

It is important to maintain hydration levels during
exercise.

Maintenance of physical activity is a good predictor of
long-term weight loss.

An energy deficit of 500 to 1000 kilocalories per day is
recommended for weight loss, with a reduction in fat
intake to less than 30 per cent of total calories.

A drastic reduction in calorie intake, as sometimes
occurs in athletes ‘making weight’ or in the female
triad syndrome (featuring disordered eating,
amenorrhoea and osteoporosis), leads to long-term
adverse health consequences.
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Eating to win: activity, diet and weight control
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Eating to win: activity, diet and weight control
References
Bean, A. (2006) The Complete Guide to Sports Nutrition, London, A &
C Black.
Burke, L.M. (2007) ‘Sports nutrition’ in Mann, J. and Truswell, A.S.
(eds) Essentials of Human Nutrition (3rd edn), Oxford, Oxford
University Press.
Goulding, A. (2007) ‘Major minerals: calcium and magnesium’ in
Mann, J. and Truswell, A.S. (eds) Essentials of Human Nutrition (3rd
edn), Oxford, Oxford University Press.
NHS (2006) Statistics on obesity, physical activity and diet:
England, 2006, London, The Information Centre.
Sharkey, B.J. and Gaskill, S.E. (2007) Fitness & Health (6th edn),
Leeds, Human Kinetics.
Skidmore, P. (2007) ‘Macronutrient intakes and their role in
obesity’, British Nutrition Bulletin, vol. 32 (supplement, pp. 4-13.
Tremblay, A., Almeras, N., Boer, J., Kranenberg, E.K. and
Despres, J.P. (1994) ‘Diet composition and post-exercise energy
balance’, American Journal of Clinical Nutrition, vol. 59, pp. 975-9.
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Eating to win: activity, diet and weight control
Acknowledgements
Except for third party materials and otherwise stated (see terms and
conditions), this content is made available under a Creative
Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.
The material acknowledged below is Proprietary and used under
licence (not subject to Creative Commons Licence). Grateful
acknowledgement is made to the following sources for permission
to reproduce material in this free course:
Course image: Ryosuke Yagi in Flickr made available under
Creative Commons Attribution 2.0 Licence.
Every effort has been made to contact copyright owners. If any
have been inadvertently overlooked, the publishers will be pleased
to make the necessary arrangements at the first opportunity.
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This free course is adapted from a former Open University course
called 'Introduction to sport, fitness and management (E112)'.
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Eating to win: activity, diet and weight control
Reading 1 Activity and weight
control
Discussion
The key message of this chapter is that, in weight control, neither
exercise nor diet alone result in the same level of longer-term
success as exercise with diet.
Back to Session 1 Activity 1
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Eating to win: activity, diet and weight control
Reading 2 Fitness and fat
Discussion
The section on cholesterol underlines the fact that with improved
fitness you receive additional benefits including a healthier blood
lipid profile, with lower LDL (low-density lipoprotein) and higher
HDL (high-density lipoprotein) levels. There is a direct relationship
between LDL levels and CHD, whereas as HDL rises, the
incidence of heart disease declines.
Back to Session 3 Activity 1
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Assessing the effectiveness of your
eating strategy
Discussion
Overall, a low-fat diet with plentiful low GI carbohydrates is
desirable. Did you achieve this? To prepare for exercise, highcarbohydrate meals and snacks are needed to maximise stores.
Both immediately before and during exercise that lasts more than
one hour, carbohydrate foods with a high GI value will promote the
storage of glucose as glycogen in the muscles. A high GI value
post-exercise snack within two hours of exercise should be
followed later by a low to moderate GI carbohydrate-based main
meal. Were your snacks appropriate? Rehydration, both during
and after exercise, is also important for recovery. Did you drink
plenty of fluid at the appropriate times? If you are fully hydrated
your urine will be a pale straw colour, no darker.
Back to Session 3 Activity 2
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Reading 3 Blood lipids
Discussion
The function of the LDLs is to carry cholesterol from the liver to the
tissues where it is needed. The HDLs are responsible for the
removal of surplus LDLs from the tissues to be taken back to the
liver for disposal (see Figure 1). Therefore, HDLs are regarded as
good cholesterol and LDLs as bad cholesterol. (To help remind
you: LDL cholesterol is Less healthy, HDL cholesterol is Healthy.)
There are clear guidelines as to what are acceptable cholesterol
levels and levels associated with an increased risk of CHD. These
levels are shown in Table 2. Excess amounts of cholesterol in the
blood can increase the risk of cholesterol being deposited onto the
artery walls. As the cholesterol is laid down in the artery walls, the
artery space will start to narrow and it will cause a hardening of the
artery wall. The resulting loss of elasticity to the artery wall and
smaller space to transport blood is the start of CHD and can cause
angina.
Back to Session 4 Activity 1
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Figure 2 It is important to maintain
hydration levels during exercise.
Description
Figure 2 It is important to maintain hydration levels during exercise.
Back to Session 5 Figure 1
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Figure 3 Adverse effects of
dehydration on work capacity
(Greenleaf, 1992).
Description
Figure 3 Adverse effects of dehydration on work capacity (Greenleaf, 1992).
Back to Session 5 Figure 2
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Figure 4 The energy concentration
of different types of sports drink.
Description
Figure 4 The energy concentration of different types of sports drink.
Back to Session 5 Figure 3
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