Transcript Physical activity - HCC Learning Web

Nutrients, Fitness, and
Physical Activity
Introduction
Nutrition & fitness have a two-way relationship
 Optimal nutrition contributes to athletic performance &
 Conversely, regular exercises contribute to a person’s ability to use
& store nutrients optimally
 Together, the two are indispensable to a high quality of life
 Fitness, like good nutrition, is an essential component of
good health
Introduction
 Nutrition and physical activity are interactive
 Each influences the other
 The working body demands all three energy-yielding
nutrients
 The body also needs protein and a host of supporting
nutrients to build lean tissue
Introduction
 Physical activity benefits the body’s nutrition by
helping to regulate the use of fuels
 Pushing the body composition toward the lean
 Increasing the daily caloric allowance

With more calories come more nutrients and other beneficial
constituents of foods
Introduction
 Improvement is not only possible but an inevitable
consequence of becoming more active
 As you improve your physical fitness, you not only feel
better and stronger, but you look better
 Physically fit people walk with confidence and purpose

Posture and self-image improve along with physical fitness
Introduction
 The more active you are the more fit you are likely
to be

Fitness builds slowly and so activity should increase
gradually

For beginners, consistency is very important

Establish a regular pattern of physical activity first

Plan to increase that amount over time

View your exercise time as a lifelong commitment
Fitness
 Fitness depends on a certain minimum amount of
 Physical activity

Bodily movement produced by muscle contractions that
substantially increase energy expenditure
 Exercise

Planned, structured, and repetitive bodily movement that
promotes or maintains physical fitness
Fitness
 When you exercise, changes occur in your body:



You breathe harder
Your heart beats faster, and
Your muscles stretch and strain.
 If you exercise regularly, you adapt to the exercise you
perform and as a result can continue for a few minutes
longer, lift a heavier weight, or stretch a millimeter farther.
 This is known as the overload principle
Benefits of Fitness
 People who regularly engage in just moderate physical
activity live longer on average than those who are
physically inactive

A sedentary lifestyle ranks with smoking and
obesity as a risk factor for developing
cardiovascular disease, some forms of cancer,
stroke, diabetes, and hypertension
Benefits of Physical Activity Include












Increase self-confidence
More energy
Less stress & anxiety
Improved sleep
Enhanced immunity
Lower risk of heart disease
Lower risk of certain cancer
Stronger bones
Lower risk of diabetes
Lower risk of high blood pressure
Improve quality of life
Increase independence in life’s later years
Benefits of Fitness
 Our bodies need Regular & Moderate Exercise that gets our


Heart beat faster
Muscle work harder
 Physiologically speaking, overall fitness is a balance
between different body systems
The Four Components of Fitness
 The body’s ability to meet physical demands, composed of
four components:




Cardiovascular or Cardiorespiratory Endurance
Muscle endurance
Flexibility
Body Composition
Cardiorespiratory endurance
 How long you can jog or ride your bike depends on the
ability of your cardiovascular and respiratory systems.
 That referred to jointly as the cardiorespiratory system, to
deliver oxygen and nutrients to your tissues and remove
wastes.
 Cardiorespiratory endurance is enhanced by regular
aerobic exercise.
Cardiorespiratory endurance
 Regular aerobic exercise strengthens the heart muscle and
increases the amount of blood pumped with each
heartbeat.
 This in turn decreases resting heart rate, the rate at which
the heart beats when the body is at rest to supply blood to
the tissues.
 The more fit you are, the lower your resting heart rate and
the more blood your heart can pump to your muscles
during exercise.
Cardiovascular Conditioning
 How Does Cardiovascular Training Benefit the Heart?
 Blood HDL increases
 Effective activities elevate the heart rate, are sustained
for longer than 20 minutes, and use more of the largemuscle groups of the body

swimming, cross-country skiing, rowing, fast walking,
jogging, fast bicycling, soccer, hockey, basketball, in-line
skating, lacrosse, rugby
Cardiovascular Conditioning
 To make these gains you must elevate your heart beat
This elevated heart beat is called


Target heart rate
 That must be considerably faster than resting rate but not so fast as
to strain it
 To achieve this goal you must work up to the point of which
you can exercise aerobically for at least 20 minutes or more.
Cardiovascular Conditioning
 As a rule of thumb
 The average resting plus rate for adult is around 70 beats
per minute
 Can be higher or lower
 Active people may have resting plus rates of 50 or even
lower
Cardiovascular Conditioning
 Estimate Your Maximum Heart Rate (MHR)
 Subtract your age from 220. This provide an estimate of the MHR

Should never exercise at this rate
 Determine your Target Heart Rate range
 Multiply MHR by 60 & 85 % to find your upper & lower limits
 Example

Age 25

MHR: 220-25= 195

Range: 0.66x195=128

0.85x195=165
Muscle strength and endurance
 Greater muscle strength enhances the ability to perform
tasks such as pushing or lifting.
 In daily life, this could mean:
 lifting a gallon of milk off the top shelf of the refrigerator with
one hand
 carrying a full trash can out to the curb, or
 moving a couch into your new apartment
Muscle strength and endurance
 Greater muscle endurance enhances your ability to
continue repetitive muscle activity, such as:
 shoveling snow or raking leaves.
 Muscle strength and endurance are increased by repeatedly
using muscles in activities that require moving against a
resisting force.
 This type of exercise is called either strength-training
exercise or resistance-training exercise and includes
activities such as weight lifting
Flexibility
 Flexibility determines your range of motion— how far you
can bend and stretch muscles and ligaments.
 If your flexibility is poor, you cannot easily bend to tie your
shoes or stretch to remove packages from the car.
 Improving flexibility improves performance in certain
activities and may reduce your risk of injuries such as:

pulled muscles and

strained tendons
Body composition
 Individuals who are physically fit have a greater proportion
of muscle and a smaller proportion of fat than do unfit
individuals of the same weight .
 The amount of body fat a person has is also affected by
gender and age.
Benefits of Fitness
The Essentials of Fitness
 Three things are needed for Physical activity
 Oxygen
 Water
 Source of Energy
The Essentials of Fitness
 Physical activity need not be strenuous to achieve
health benefits
 The institute of medicine recommends that we spend a total of at
least 60 minutes on most day of the week engaged in any one of
numerous forms of physical activities
 These 60 minutes can be accumulated in relatively brief session in
period as short as 8 to 10 minutes
 Total amount of activity is more important than the manner in
which it is carried out
The Essentials of Fitness
 How Do My Muscles become Physically Fit?
 Overload



An extra physical demand placed on the body
An increase in the frequency, duration, or intensity of an
activity
A principle of training is that for a body system to improve, it
must be worked at frequencies, durations, or intensities that
increase by increments
The Essentials of Fitness
 Hypertrophy

An increase in size in response to use
 Muscle cells and tissues respond to an overload of
physical activity by gaining strength and size

A response called hypertrophy
 If not called on to perform, muscle cells dwindle and
weaken; they atrophy
The Essentials of Fitness
 A variety of physical activities produces the best
overall fitness
 People need to work different muscle groups from day to
day
 For balanced fitness



Stretching enhances flexibility
Weight training develops muscle strength and endurance
Aerobic activity improves cardiorespiratory endurance
The Essentials of Fitness
 Aerobic
 Requiring oxygen
 Aerobic activity strengthens the heart and lungs by
requiring them to work harder than normal to deliver
oxygen to the tissues
Anaerobic Metabolism
 Anaerobic Exercise (without Oxygen)
 When the muscles exertion becomes greater enough
that their energy demand outstrips the oxygen supply,
they must also rely on Anaerobic metabolism for energy.
 Anaerobic pathway can only burn carbohydrate for fuel,
it draws heavily on your limited stores of carbohydrates
 Thanks to anaerobic metabolism, you can dash out of
the way of an oncoming car .
 Unfortunately, this system is extremely inefficient
Anaerobic Metabolism
 0nly 5% of Carbohydrate’s energy-producing
potential is harness by this pathway.
 It produces Lactic acid – partly broken down
portion of glucose.
 When lactic acid build up in muscles it causes
burning pain and leads to muscle exhaustion if it
is not drained away.
Anaerobic Metabolism
 At low intensities, lactic acid is readily cleared
from the blood by the liver
 At higher intensities, lactic acid accumulates
 When the rate of lactic acid production exceeds
the rate of clearance, intense activity can be
maintained for only one to three minutes
Anaerobic Metabolism
 Neither the Aerobic nor Anaerobic pathways functions
exclusively to supply energy.
 Work together, complementing and supporting each
other.
 The Carbohydrate is absolutely essential for
exercise.
 Without it, your muscles cannot perform.
 When you exercise AEROBICALLY, muscles burn
fat and extract energy from glucose more
efficiently in the presence of Oxygen, thereby
conserving your body’s limited stores of glucose.
Anaerobic Metabolism
 Glucose use during physical activity depends on the
duration of the activity
 As well as on its intensity
Energy for Exercise
 Thus, you want to exercise at an intensity that allows
your heart and lungs to keep pace with the oxygen
needs of your working muscles.
The Essentials of Fitness
 For total fitness, an exercise program should
incorporate



Aerobic Activity
Strength Training &
Stretching
The Essentials of Fitness
 It makes sense to give muscles a rest
 It takes a day or two to replenish muscle fuel supplies
and to repair wear and tear incurred through physical
activity
 Periodic rest gives muscle time to adapt to an activity

During rest, muscles build more of the equipment required to
perform the activity that preceded the rest
 The term Fitness is not restricted to the seasoned athletes
you need:





Reasonable weight
Enough flexibility
Muscle strength
Muscle endurance &
Cardiovascular Endurance
 To meet everyday demands, plus some to spare
The Components Of Fitness

Physical Conditioning




Strength
Flexibility
Muscle Endurance
Cardiovascular Endurance
FIT
F= Frequency
I= Intensity
T= Time
Physical Conditioning:
 Planned program of exercise directed toward
improving the function of a particular body system
 Placing physical demand on your body & forcing it
to do more
 This principle applies equally to all aspects of
fitness It is called OVERLOADING
Strength
 Is the ability of the muscles to work against resistance




Muscles
Tendons
Ligaments &
Connective tissues
 Become stronger
 Prevent energy
 Benefit continues to a very old age
Flexibility
 A flexible body can move as it was designed to move & will
bend rather than tear or break in response to sudden stress
 Flexibility depends on the condition & interrelationship of:




Bones
Ligaments
Muscles &
Tendons
 Flexibility tends to decrease with age but improves
response to stretching
Cardiovascular Conditioning
 Increase total blood volume so that the blood carry
more O2
 Heart muscles become stronger & larger, so each beat pumps
more blood
 Lung muscles become stronger & larger & breathing becomes
more efficient
 Circulation through arteries vein improve & the blood
pressure falls
 Muscles through out the body become firmer
Fluids and Temperature Regulation in
Physical Activity
 The body’s need for water far surpasses its need for any
other nutrient
 If the body loses too much water, its life-supporting
chemistry is compromised
Fluids and Temperature Regulation in
Physical Activity
 The exercising body loses water primarily via sweat
 Second to that, breathing costs water, exhaled as
vapor
 During physical activity, both routes can be
significant
 Dehydration is a real threat
 The first symptom is fatigue
 A water loss of even 1%-2% of body weight can reduce a
person’s capacity to do muscular work
 A person with a water loss of ≈7% is likely to collapse
Fluids and Temperature Regulation in
Physical Activity
 Sweat cools the body
 In hot, humid weather, sweat may fail to evaporate
because the surrounding air is already laden with water


Little cooling takes place and body heat builds up
In such conditions, athletes must take precautions to avoid
heat stroke
 An especially dangerous accumulation of body heat with
accompanying loss of body fluid
Fluids and Temperature Regulation in
Physical Activity
 Endurance athletes can lose 2 or more quarts of
fluid in every hour of activity
 The digestive system can only absorb about a quart or so
an hour

The athlete must hydrate before and rehydrate during and after
activity to replace all the lost fluid
 In hot weather, the digestive tract ay not be able to
absorb enough water fast enough to keep up with an
athlete’s sweat losses

Some degree of dehydration becomes inevitable
Fluids and Temperature Regulation in
Physical Activity
 Athletes who rely on thirst to govern fluid intake can
easily become dehydrated
 During activity thirst becomes detectable only after
fluid stores are depleted
 Don’t wait to feel thirsty before drinking
Water
 The best drink for most active bodies is plain cool
water
 Water rapidly leaves the digestive tract to enter the
tissues
 Water cools the body from the inside out
Water
 Endurance athletes are an exception
 They need more from their fluids than water alone
 The first priority for endurance athletes should always
be replacement of fluids

To prevent life-threatening heat stroke
 Endurance athletes need carbohydrate to supplement
their limited glycogen stores
Water
 Sports drinks offer fluids to help you offset the loss of
fluids during physical activity
 Plain water can do this
Water
 For athletes who exercise intensely for 45 minutes or
more
 Sports drinks provide an advantage over water
 Fitness water does not provide glucose and electrolytes
 Some active people may prefer its light flavor to plain
water
Water
 Carbonated beverages are not a good choice for
meeting an athlete’s fluid needs
 Although they are composed largely of water
 The air bubbles from the carbonation make a person feel
full quickly

So may limit fluid intake
Water
 Beverages that contain alcohol are inappropriate as
fluid replacements
 Alcohol is a diuretic
 It promotes the excretion of



Water
Vitamins such as thiamin, riboflavin, and folate
Minerals such as calcium, magnesium, and potassium
Fuel For Exercise
 Energy producing pathway requires oxygen & two
fuels
Glucose
 Fat
Glucose, mainly provided by the muscles & some by the
Liver

 Fatty acids, also, come mainly from fat inside the
muscles but partly from adipose tissues
Fuel For Exercise
 During rest
 The body derives a little more than half of its energy
from fatty acids


Most of the rest from glucose
A little from amino acids
Fuel For Exercise
 For Physical activity the body uses different mixtures
of fuels depending on the intensity and duration of its
activities and depending on its own prior training
Fuel For Exercise
 During physical activity
 The body adjusts its fuel mix to use the stored glucose of
muscle glycogen
 In the early minutes of activity, glycogen provides the
majority of energy the muscles use to go into action

As the activity continues, messenger molecules, including
epinephrine, flow into the bloodstream to signal the liver and
fat cells to liberate their stored nutrients
 Primarily glucose and fatty acids
Fuel For Exercise
 As activity continues
 Glucose from the liver’s stored glycogen and dietary
glucose absorbed from the digestive tract also become
important sources of fuel for muscle activity
Fuel For Exercise

Longer the exercise lasts or the more intense it is,
the more glucose a person uses
 Jogging & brisk walking, in which the body can meet the
oxygen demand body use glycogen more conservatively
 For 1st 20 minutes or so, body uses glycogen rapidly
 If exercise continues beyond 20 minutes glycogen use
slows down & body begins to rely more on fat
Fuel For Exercise
 People who run out of muscle glycogen “hit the
wall”
 They must slow down their pace because muscle
glycogen is no longer available
 Liver can release small amount of glucose to briefly
delay body shutdown
 When blood glucose dip too low, the nervous system
function comes almost to a halt
Fuel For Exercise

Another factor that influences glycogen use
during exercise is:

How trained the person is
 Untrained muscles quickly & easily extract energy from
glucose
 Trained muscles adapt & pack their cells with more fatburning enzymes
 The amount of glycogen present in the muscles
before exercise also influence glycogen use
Fuel For Exercise
 A classic report compared fuel use during activity by
three groups of runners, each on a different diet
 For several days before testing, one of the groups ate a
normal mixed diet; a second group ate a highcarbohydrate diet; the third group ate a high-fat diet
 The high-carbohydrate diet enables the athletes to work
longer before exhaustion
Activity Intensity, Glucose Use, and
Glycogen Stores
 The body’s glycogen stores are much more limited
than its fat stores
 Glycogen can easily support everyday activities but is
limited to less than 2,000 calories of energy

How long a person’s glycogen will last while exercising
depends on both diet and intensity of the activity
 Fat stores can usually provide more than 70,000 calories
and fuel hours of activity without running out
Activity Duration
Affects Glucose Use
 In the first 10 minutes or so of activity
 The active muscles rely almost entirely on their own
stores of glycogen
 Within the first 20 minutes or so of moderate activity
 A person uses up about one-fifth of the available
glycogen
Activity Duration
Affects Glucose Use
 As the muscles devour their own glycogen, they
increase their uptake of blood glucose dramatically
 During moderate activity, blood glucose declines slightly

Reflecting its use by the muscles
Activity Duration
Affects Glucose Use
 A person who exercises moderately for longer than 20
minutes begins to use less glucose and more fat for fuel
 Still, glucose use continues

If the activity goes on long enough and at a high enough
intensity, muscle and liver glycogen stores will run out almost
completely
Activity Duration
Affects Glucose Use
 Glycogen depletion generally occurs after about two
hours of vigorous exercise
 Physical activity can occur for a short time thereafter
only because the liver produces some glucose from
available lactic acid and certain amino acids

This minimum amount of glucose may briefly forestall
exhaustion
 But when hypoglycemia accompanies glycogen depletion, it
brings nervous system function almost to a halt
Activity Duration
Affects Glucose Use
 Maintaining Blood Glucose for Activity
 Eat a high-carbohydrate diet regularly
 Take glucose (usually in sports drinks) periodically
during endurance activities
 Eat carbohydrate-rich foods after performance
 Train the muscles to maximize glycogen stores

Carbohydrate loading
Activity Duration
Affects Glucose Use
 Glucose During Activity
 Glucose ingested before and during exhausting
endurance activities makes its way from the digestive
tract to the working muscles

Augmenting dwindling internal glucose supplies from the
muscle and liver glycogen stores

Especially during games which last for hours and demand
repeated bursts of intense activity, athletes benefit from
carbohydrate-containing drinks taken during the activity
Activity Duration
Affects Glucose Use
 Before concluding that sugar might be good for your own
performance, consider first whether you engage in
endurance activity
 Do you run, swim, bike, or ski nonstop at a rapid pace
for more than 45 minutes at a time, or do you compete in
games lasting for hours?
 If not, the sugar picture changes

For an everyday activity lasting less than 60 minutes, sugar
probably won’t help (or harm) performance
Activity Duration
Affects Glucose Use
 Even in athletes, extra carbohydrate does not benefit
those who engage in sports in which fatigue is
unrelated to blood glucose
 100-meter sprinting
 Baseball
 Casual basketball
 Weight lifting
Activity Duration
Affects Glucose Use
 Carbohydrate Loading
 A regimen of moderate exercise, followed by eating a
high-carbohydrate diet
 Enables muscles to temporarily store glycogen beyond
their normal capacity

Can nearly double muscle glycogen concentration
 A.k.a. glycogen loading or glycogen supercompression
Activity Duration
Affects Glucose Use
 Carbohydrate Loading
 Glycogen storage occurs slowly in the plan presented in
Table 10-2
 Athletes must alter their training in the days just before
the event
Activity Duration
Affects Glucose Use
 Extra glycogen gained through carbohydrateloading can benefit an athlete who must keep
going for 90 minutes or longer
 Those who exercise for shorter times simply need a
regular high-carbohydrate diet
 In a hot climate, extra glycogen confers an
additional advantage
• As glycogen breaks down, it releases water
• Which helps to meet the athlete’s fluid needs
Activity Duration
Affects Glucose Use
 Glucose After Activity
 Eating high-carbohydrate foods after physical activity
also enlarges glycogen stores


Train normally, and then, within 2 hours after physical
activity, consume a high-carbohydrate meal
This method accelerates the rate of glycogen storage by 300%
for a while
 This is especially important to athletes who train hard
more than one time a day
Activity Duration
Affects Glucose Use
 For athletes who don’t feel like eating right after
exercise, high-carbohydrate energy drinks are
available
 Fruit-flavored commercial beverages used to restore
muscle glycogen after exercise or as a pregame beverage
 For athletes wishing to maximize muscle glycogen
synthesis after strenuous training, eating foods
with a high glycemic index may restore muscle
glycogen most rapidly
To Burn More Fat
during Activity, Should Athletes Eat More Fat?
 When endurance athletes “fat load” by consuming
high-fat, low-carbohydrate diets for one to three days…
 Performance is impaired because their small glycogen
stores are depleted quickly
To Burn More Fat
during Activity, Should Athletes Eat More Fat?
 High-fat diets carry risks of heart disease
 Physical activity offers some protection against
cardiovascular disease

Even athletes can suffer heart attacks and strokes
 Most nutrition experts agree that the potential for
adverse health effects from prolonged high-fat diets
makes them an unwise choice for athletes
Should Athletes
Eat More Fat?
 A diet that overly restricts fat is not recommended
either
 Athletes who restrict fat below 20% of total energy
intake may fail to consume adequate energy and
nutrients
 Sports nutrition experts recommend that endurance
athletes consume 20%-30% of their energy from fat
Should Athletes
Eat More Fat?
 As fuel for activity, body fat stores are more important
than fat in the diet
 Fat stores can fuel hours of activity without running out
 Body fat is (theoretically) an unlimited source of energy

Even the lean bodies of runners carry enough fat to fuel
several marathons
Should Athletes
Eat More Fat?
 Early in activity, muscles begin to draw on fatty acids
from two sources
 Fats stored within the working muscles
 Fats from fat deposits such as fat under the skin

Areas with the most fat to spare donate the greatest amounts
of fatty acids to the blood
 Although they may not be the areas that one might choose to
lose fat from
 This is why “spot reducing” does not work
 Muscles do not own the fat that surrounds them
Should Athletes
Eat More Fat?
 Intensity and Duration Affect Fat Use
 The intensity of physical activity affects the percentage
of energy contributed by fat


Fat can be broken down for energy only by aerobic
metabolism
When the intensity of activity becomes so great that energy
demands surpass the ability to provide energy aerobically, the
body cannot burn more fat
 Instead, it burns more glucose
Should Athletes
Eat More Fat?
 Degree of Training Affects Fat Use
 Training stimulates muscles to develop more fatburning enzymes



Aerobically trained muscles burn fat more readily than
untrained muscles
With aerobic training, the heart and lungs become
stronger and better able to deliver oxygen to the muscles
during high-intensity activities
This improved oxygen supply enables the muscles to burn
more fat
 Intense, prolonged activity may also increase your
basal metabolic rate (BMR)
VO2 max
 VO2 max (also maximal oxygen consumption,
maximal oxygen uptake or aerobic capacity) is the
maximum capacity of an individual's body to transport
and utilize oxygen during incremental exercise, which
reflects the physical fitness of the individual. The
name is derived from V̇ - volume per time, O2 - oxygen,
max - maximum
Using Protein and Amino Acids to Build Muscles
and Fuel Activity
 Athletes use protein to build and maintain muscle and
other lean tissue structures
 And, to a small extent, to fuel activity
 The body handles protein differently during activity
than during rest
Using Protein and Amino Acids to Build Muscles
and Fuel Activity
 Protein for Building Muscle Tissue
 In the hours of rest that follow physical activity


Muscles speed up their rate of protein synthesis
 They build more of the proteins they need to perform the
activity
Eating protein, together with carbohydrate, enhances protein
synthesis
Using Protein and Amino Acids to Build Muscles
and Fuel Activity
 Whenever the body rebuilds a part of itself, it must
tear down old structures to make way for the new ones
 Physical activity, with just a slight overload, calls into
action both the protein-dismantling and proteinsynthesizing equipment of individual muscle cells that
work together to remodel muscles
Using Protein and Amino Acids to Build Muscles
and Fuel Activity
 Dietary protein provides the
needed amino acids for the
synthesis of new muscle
protein
 However, the true director of
synthesis of muscle protein is
physical activity
 Repeated activity signals the
muscle cells’ genetic material
to begin producing more of
the
proteins needed to perform
the
work at hand
Using Protein and Amino Acids to Build Muscles
and Fuel Activity
 After muscle cells have made all the decisions about
which proteins to build and when, protein nutrition
comes into play
 During muscle-building phases of training, a weight
lifter might add between 0.25 ounce and 1 ounce of
protein to existing muscle mass each day
 This extra protein comes from ordinary food
Using Protein and Amino Acids to Build Muscles
and Fuel Activity
 The DRI committee does not recommend greater-
than-normal protein intakes for athletes
 Other authorities do

A joint position paper by the American Dietetic Association
and the Dietitians of Canada recommend protein intakes
somewhat higher than the 0.8 gram of protein per kilogram of
body weight recommended for sedentary people
 Athletes who eat a balanced, high-carbohydrate
diet that provides enough total energy also
consume enough protein
 They do not need special foods, protein shakes, or
supplements
Vitamin and Minerals Keys to Performance
 Many vitamins and
minerals assist in
releasing energy from
fuels and transporting
oxygen
Vitamin and Minerals Keys to Performance
 Nutrient supplements do not enhance the
performance of well-nourished athletes or active
people
 Deficiencies of vitamins and minerals do impede
performance
 Regular, strenuous physical activity increases the
demand for energy

Athletes and active people who eat enough nutrient-dense
foods to meet energy needs also meet their vitamin and
mineral needs
Vitamin and Minerals Keys to Performance
 Taking vitamin or mineral supplements just before
competition will not enhance performance
 Most vitamins and minerals function as small parts of
larger working units
 After entering the blood, they have to wait for the cells
to combine them with their appropriate other parts so
they can do their work

This takes hours or days
 If you want to excel physically
 Apply the most accurate nutrition knowledge with
dedication to rigorous training
 A diet that provides ample fluid and consists of a variety
of nutrient-dense foods in quantities to meet energy
needs will enhance athletic performance and overall
health
Controversy: Ergogenic Aids: Breakthroughs,
Gimmicks,
 Store shelves and the Internet abound with ergoenic
aids
 Each striving to appeal to performance-conscious people
 Protein powders, amino acid supplements, caffeine pills,
steroid replacers, “muscle builders,” vitamins, and more
 In light of the evidence, this section concludes what
most people already know
 Consistent training and sound nutrition serve an athlete
better than any pill, powder, or supplement
 Amino Acid Supplements
 Are unnecessary
 Healthy athletes eating a well-balanced diet never need
them
 In a few cases these supplements have proved dangerous


Amino acids complete for carriers
 An overdose of one can limit the availability of some other
needed amino acid
Can lead to digestive disturbances and excess water
accumulation in the digestive tract
 Carnitine
 A nonessential nutrient



Often marketed as a “fat burner’
In the body, does help to transfer fatty acids across the
membrane that encases the cell’s mitochondria
In scientific studies, carnitine supplementation for 7 to 14 days
neither raised muscle carnitine concentrations nor influenced
fat or carbohydrate oxidation
 Nor do such supplements enhance exercise performance
 Chromium Picolinate
 Chromium is an essential trace mineral involved in
carbohydrate and lipid metabolism
 The great majority of studies show no effects of
chromium picolinate on body fatness, lean body mass,
strength, or fatigue
 Eating extra protein will not stimulate muscle growth
 Muscle growth is stimulated by physically demanding
activity
 Not by excess protein
 Purified protein preparations contain none of the
other nutrients needed to support the building of
muscle protein
 An entire array of nutrients from food is required
 Hormone Preparations
 These substances are clearly damaging to the body
 Don’t consider using these products