Transcript Nutrition Now J. Brown

Chapter 10
Nutrition and
Fitness
© 2007 Thomson - Wadsworth
Ask Yourself
1.
2.
3.
4.
5.
Regular exercise can help people increase
their lean body mass and reduce their fat
tissue.
Less than 25% of U.S. adults exercise
adequately.
People who fail to exercise regularly are
more likely to fall prey to degenerative
diseases such as heart disease, osteoporosis,
and diabetes.
Essentially, to be fit means to be at desirable
weight and to have strong muscles.
People should never push themselves to
exercise longer or harder than they can
easily manage to do.
© 2007 Thomson - Wadsworth
Ask Yourself
6.
Of all the components of fitness,
cardiovascular endurance has the most
impact on health and longevity.
7. If you run out of breath, it is a sign that your
heart and lungs are not strong enough to
perform the desired tasks.
8. In a muscular athlete who stops exercising,
much of the muscle tissue turns to fat.
9. The use of steroid hormones can cause a
disfiguring disease.
10. Athletes can lose 2 or more quarts of fluid
during every hour of heavy exercise and
must rehydrate before, during, and after
exercising.
© 2007 Thomson - Wadsworth
Benefits of Physical Activity
• Being fit is more
than being free of
disease; it is feeling
full of vitality and
enthusiasm for life.
• Fitness: the body’s
ability to meet
physical demands,
composed of four
components:
 Strength
 Flexibility
 Muscle endurance
 Cardiovascular
endurance
Fitness, like good nutrition,
is an essential component
of good health.
© 2007 Thomson - Wadsworth
Benefits of Physical Activity
• Increased selfconfidence
• Easier weight control
• More energy
• Less stress and
anxiety
• Improved sleep
• Enhanced immunity
• Lowered risk of heart
disease
• Lowered risk of
certain cancers
• Stronger bones
• Lowered risk of
diabetes
• Lowered risk of high
blood pressure
• Increased quality of
life
• Increased
independence in
life’s later years
© 2007 Thomson - Wadsworth
Lifetime Fitness
© 2007 Thomson - Wadsworth
Lifetime Fitness
• The Institute of Medicine recommends
that we spend a total of at least 60
minutes on most days of the week
engaged in physical activity.
• For total fitness include aerobic activity,
strength training and stretching.
• Fitness builds slowly—increase
gradually.
• Establish a regular pattern of activity
and then aim to increase over time.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Lifetime Fitness
• The American College of
Sports Medicine (ACSM)
recommends an exercise
stress test for men over 40
and women over 50 who
plan to start a vigorous
exercise program.
• Exercise stress test: a
test that monitors heart
function during exercise to
detect abnormalities that
may not show up under
ordinary conditions;
exercise physiologists and
trained physicians or health
care professionals can
administer the test.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Components of Fitness
Physical Conditioning
• A planned program of exercise directed toward
improving the function of a particular body
system.
• Overload: Placing regular, physical demand
on the body and forcing the body to do more
will cause it to adapt and function more
efficiently.
 A principle of training is that for a body
system to improve, its workload must be
increased by increments over time.
© 2007 Thomson - Wadsworth
Components of Fitness
Physical Conditioning
• Applying overload to
increase strength and
size:
 Increase frequency
(more often)
 Increase intensity
(more strenuous)
 Increase time (exercise
longer)
• Hypertrophy: an increase
in size in response to use.
• Atrophy: a decrease in
size in response to disuse.
© 2007 Thomson - Wadsworth
Components of Fitness
• Strength: the ability of
muscles to work against
resistance.
• Purpose of strength
training:
 Build well-toned muscles
to help accomplish work.
 Strong muscles, tendons,
and ligaments help to
prevent injury both at
work and play.
 Helps with weight loss by
increasing lean muscle
mass, thereby increasing
metabolic rate.
© 2007 Thomson - Wadsworth
Components of Fitness
• Flexibility: the ability to bend or extend
without injury; flexibility depends on the
elasticity of the muscles, tendons, and ligaments
and on the condition of the joints.
 Flexibility decreases with aging but improves in
response to stretching.
• Static stretches: stretches that lengthen
tissues without injury; characterized by longlasting, painless, pleasurable stretches.
 After a light warm-up, stretch muscles that will be used
in your main activity.
 Stretch at the end of your activity to gradually slow
down the activity and lengthen the muscles.
© 2007 Thomson - Wadsworth
Components of Fitness
Endurance: the ability
to sustain an effort for a
long time. Two types
are:
• Muscle endurance: the
ability of a muscle to
contract repeatedly
within a given time
without becoming
exhausted.
• Cardiovascular
endurance: the ability
of the cardiovascular
system to sustain effort
over a period of time.
© 2007 Thomson - Wadsworth
Nutrition and Fitness:
Forever Young…
• The body (and how it
works) of modern humans
was designed over 100,000
years ago.
• Inactivity is an abnormal
state because our bodies
have been “programmed”
to expect physical activity.
 Thus causing metabolic
dysfunctions leading to
a host of chronic health
conditions.
© 2007 Thomson - Wadsworth
Yesterday’s Genes, Today’s
Lifestyle
• Nearly all of your
biochemistry and
physiology was finetuned to conditions
of life that existed
earlier than 10,000
years ago.
 What we eat has
changed more in
the last 40 years
than in the
previous 40,000
years.
• 12 easy ways to be
sedentary:












Cellular phones
Computer games
Dishwashers
Drive-through
windows
E-mail/Internet
Escalators & elevators
Food delivery services
Garage door openers
Housekeeping and
lawn services
Moving sidewalks
Remote controls
Shopping by phone
© 2007 Thomson - Wadsworth
• Preagricultural
hunter-gatherers
• Industrialized
modern humans
 Burned ~3000
calories/day
 Moderate physical
activity >30 min/day
 Feast or famine
 Lean wild game or
fish
 Uncultivated fruits &
vegetables
 Burn ~1800
calories/day
 Sedentary
 Abundance of food
 Grain-fattened meats
 Refined sugar
© 2007 Thomson - Wadsworth
Choose Your Weapon
Choose Your
Weapon…
 …against the lifethreatening
diseases
associated with
sedentary aging
• There is a need for
physical activity
throughout life.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Make exercise a habit. Choose
an activity you enjoy.
Tips for Sustaining an Exercise Program:
• First, check with your physician.
• Use a gradual approach and set realistic goals.
• Find the time that is right for you to exercise.
• Don’t overdo it. No pain no gain is a myth.
• Find an exercise buddy.
• Don’t focus on weight. Focus on how you feel and
how much better your clothes fit.
© 2007 Thomson - Wadsworth
Energy for Exercise
• Your body runs on water,
oxygen, and food—
primarily carbohydrate
and fat.
• The chemical reactions
that use these
substances to make
energy are called
metabolism.
• Your body has two
interrelated energyproducing systems:
 Aerobic: requiring
oxygen.
 Anaerobic: not
requiring oxygen.
© 2007 Thomson - Wadsworth
Energy for Exercise
• Cardiovascular
conditioning or training
effect: the effect of regular
exercise on the
cardiovascular system—
including improvements in:
 Heart
 Lung
 Muscle function
 Increased blood volume
• Target heart rate: the
heartbeat rate that will
achieve a cardiovascular
conditioning effect for a
given person—fast enough
to push the heart but not so
fast as to strain it.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Energy for Exercise
Example: Jennifer, age 25
 Maximum heart rate:
220–25=195
 Lower limit (55%) of
target heart rate range:
0.55x195=107
 Upper limit (90%) of
target heart rate range:
0.90x195=176
• Target heart rate range:
107 to 176 beats per
minute.
© 2007 Thomson - Wadsworth
Fuels for Exercise
Glucose Use During Exercise
• Glucose comes from carbohydrate-rich foods.
• Your body stores glucose in your liver and
muscles as glycogen.
• During exercise, the body supplies glucose to
the muscles from the stores of glycogen in the
liver and in the muscles themselves.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Fuels for Exercise
For most
people, fat isn’t
used much as a
fuel for exercise
until you’ve
been working
out aerobically
for at least 20
min, and it is
not used as a
primary fuel
until after 2
hours.
© 2007 Thomson - Wadsworth
Fuels for Exercise
Fat Use during Exercise
• When you exercise, the fat
your muscles burn comes
from the fatty deposits all
over the body.
• A person who is of
desirable body weight may
store 25 to 30 pounds of
body fat but only about 1
pound of carbohydrate.
• Although your supply of fat
is almost unlimited, the
ability of your muscles to
use fat for energy is not.
© 2007 Thomson - Wadsworth
A high-carbohydrate diet can increase an athlete’s endurance. In this
study: fat and protein diet = 94% of calories from fat & 6% from
protein; normal mixed diet = 55% carbohydrate; & highcarbohydrate diet = 83% carbohydrate.
© 2007 Thomson - Wadsworth
Protein Needs for Fitness
© 2007 Thomson - Wadsworth
Fluid Needs and Exercise
• Replenishing fluid lost during
exercise is easily accomplished
by drinking fluid before,
during, and after exercise.
• Ignoring body fluid needs can
hinder performance and
increase risk of heat-related
injury.
 Heat stroke: an acute and
dangerous reaction to heat
buildup in the body,
requiring emergency
medical attention; also
called sun stroke.
© 2007 Thomson - Wadsworth
Fluid Needs and Exercise
© 2007 Thomson - Wadsworth
Fluid Needs and Exercise
Fluid Replacement
Drinks
• Sports drinks are designed to
enhance the body’s use of
carbohydrate and water.
• The carbohydrate in a sports
beverage serves three
purposes during exercise:
 Becomes an energy source
for working muscles.
 Helps maintain blood
glucose at an optimum
level.
 Helps increase the rate of
water absorption from the
small intestine, helping
maintain plasma volume.
© 2007 Thomson - Wadsworth
Fluid Needs and Exercise
© 2007 Thomson - Wadsworth
Vitamins & Minerals for Exercise
Vitamins
• Vitamins are the links and
regulators of energyproducing and musclebuilding pathways.
• Without them, your
muscles’ ability to convert
food energy to body energy
is hindered and muscle
protein formation is slowed.
• The B vitamins are of
special interest to athletes
because they govern the
energy-producing reactions
of metabolism.
Minerals
• Iron is a core
component of the
body’s oxygen taxi
service: hemoglobin
and myoglobin.
• A lack of oxygen
compromises the
muscles’ ability to
perform.
• Sports anemia: a
temporary condition of
low blood hemoglobin
level, associated with
the early stage of
athletic training.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Vitamins & Minerals for Exercise
Bones and Exercise
• Stress fracture: bone
damage or breakage
caused by stress on
bone surfaces during
exercise.
• Amenorrhea: cessation
of menstruation
associated with
strenuous athletic
training.
© 2007 Thomson - Wadsworth
Food for Fitness
• The best nutrition
prescription for peak
performance is a
well-balanced diet.
• Two critical nutrition
periods for the
athlete are the
training diet and the
precompetition diet.
• An eating plan that
supplies 60% of
calories from
complex
carbohydrate, 15%
of calories from
protein, and 25% of
calories from fat will
enable both athletes
and fitness
enthusiasts to supply
muscles with a
proper fuel mix and
maintain health.
© 2007 Thomson - Wadsworth
Planning the Diet
• A diet rich in
complex
carbohydrate and
low in fat not only
provides the best
balance of
nutrients for
health but also
supports physical
activity best…
• Choose foods to
provide nutrients
as well as
calories…
• An athlete may
be able to eat
more food by
consuming it in
six or eight meals
each day rather
than in three or
four meals…
© 2007 Thomson - Wadsworth
The Pregame Meal
The Pregame Meal
• The best choices for the
meal before a
competitive event are
foods that are high in
carbohydrate and low in
fat, protein, and fiber…
 Fiber is not desirable
right before physical
exertion:
• It stays in the
digestive tract too
long.
• Attracts water out
of the blood.
• A high-carbohydrate
meal will support blood
glucose levels during
competition.
• For pregame meals and
snacks, choose: grape
juice, apricot nectar…
• Stay away from higherfat foods.
• Include plenty of fluids.
• Any meal should be
finished a good 2 to 4
hours before the event…
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
Sample Breakfasts
© 2007 Thomson - Wadsworth
Athletes and
Supplements—Help
or Hype?
• Ergogenic aids: anything
that helps to increase the
capacity to work or
exercise.
ergo = work
genic = give rise to
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Ergogenic aids: anything that helps to increase
the capacity to work or exercise.
ergo = work
genic = give rise to
An endless array of
ergogenic aids are
marketed to athletes
and other sports
enthusiasts. Although
big on claims, few are
based on scientific
evidence.
© 2007 Thomson - Wadsworth
Can they enhance the
benefits from workouts?
Ergogenic Aids:
• Substances that increase the
ability to exercise harder.
Most are costly versions of vitamins,
minerals, sugars and other
substances easily found in a balanced
diet.
© 2007 Thomson - Wadsworth
Athletes and Supplements
• Placebo effect: an improvement in a
person’s sense of well-being or physical health
in response to the use of a placebo (a
substance having no medicinal properties or
medicinal effects).
• Anabolic steroids: synthetic male
hormones with a chemical structure similar to
that of cholesterol.
 Such hormones have wide-ranging effects
on body functioning.
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth