Transcript Exercise and Nutrition

Exercise and Nutrition
Copyright 2010. PEER.tamu.edu
Benefits of Exercise
• How do you think exercise
helps your body?
• Exercise:
– Helps prevent obesity
– Strengthens muscle, bones,
and joints
– Reduces mental stress
– Makes you feel better, have
more energy
– Helps you sleep better at
night
Why Does Exercise Help Prevent
People From Getting Overweight?
Exercise
makes
muscles
contract
Muscle contraction
requires energy
Energy comes from
breakdown of food
Unused energy is
stored as fat
Muscle Contraction
• Muscles have many fibers
• Fibers contain protein filaments
(thick and thin) that slide past each
other.
• The sliding is caused by ratchetlike movements of parts of the
proteins
• The ratchet-like movements
consume energy
Do you know what a ratchet-like
movement is? Have you ever seen a
ratchet wrench? Such wrenches can
be set to turn in only one direction
because it has a gear-like toothed
wheel that grabs only one way when
the handle is cranked.
This is what it looks like:
See slide notes on how joints work
Two Kinds of Muscle Action
Both shorten the fibers, consume energy, and exert force,
but only one shortens the actual muscle
• Isotonic: muscle
shortens (as in
flexing the biceps)
• Isometric: muscle does
not shorten (as in
carrying a suitcase)
Review Time
• How does exercise help prevent people
from being overweight?
• How do muscles contract?
• What are the two types of muscle
action?
Food As The Energy Source
• Body uses glucose as its energy source
• Food breaks down to glucose, a simple sugar
– table sugar (sucrose) is a compound that has two
simple sugars, glucose and fructose
– In plants, glucose is produced by photosynthesis
and builds up into proteins and carbohydrates in
the plants
Oxygen
Hydrogen
Carbon
A Molecule of Glucose
Can you tell what
the chemical
formula for
glucose is from
looking at this
diagram?
Producing the Energy From Glucose
• Process is called “glycolysis”
(glyco = glucose, lysis =
break down)
• Energy is released by
enzymes in a chain of
reactions that break bonds
between atoms in glucose.
Bond energy is what is
released.
• Energy release occurs in
small steps, to reduce loss
as heat
Aerobic Metabolism
• Complete breakdown of
glucose requires oxygen.
• Vigorous exercise requires
lots of energy and lots of
oxygen.
• Therefore, vigorous
exercise (aerobic exercise)
breaks down a lot of
glucose that otherwise
would be used to build fat.
Calories
• Calories are a unit of measurement
of food energy. They measure the
amount of potential heat energy
contained in the chemical bonds of
a food.
• People need a certain amount of
calories per day.
• For the average teenage girl, the
recommended daily allowance is
2200 calories. The average teenage
boy needs 2500-3000 calories.
•
See slide note for an activity on measuring calories in
foods.
Calories in Foods
• Protein and Carbohydrates
contain 4 calories per gram.
• Fat contains 9 calories per
gram!
• That's why one food with
the same serving size as
another may have far more
calories.
• A high-fat food has many
more calories than a food
that's low in fat.
½ cup of ice cream contains
178 calories
2 grams of protein
12 grams of fat and
15.5 grams of carbohydrate
½ cup of carrots contain
36 calories
1 gram of protein
0 grams of fat and
8 grams of carbohydrate
Managing Energy
Intake
To maintain weight:
•Energy consumed must
be EQUAL to energy
USED by the body.
•Food intake and
exercise are in balance.
•Make sure food
choices are healthy and
contain the essential
nutrients
To lose weight:
•Energy consumed must
be LESS than energy
USED by the body.
•Eat LESS, Exercise
MORE
•Make sure food
choices are low in
calories but still contain
essential nutrients
Calorie In = Calories Out
Calorie In < Calories Out
Stop and Remember:
• What is the energy source for
exercise?
• How is this energy source broken
down in the body?
• What are calories?
• Why do calories in foods differ for
the same portion size?
• How should you manage your
energy if you want to lose weight?
Exercise Burns Calories!
What Kind of Exercise Would You Choose?
Learn about over 30 kinds of activities,
from Ballet to Yoga
Stretch Before and After: Here Are Some Yoga Stretches
Famous Body Builders
• Do you know about Charles
Atlas?
– He was a weakling who
became a famous body builder
by using isometrics
• How about Arnold
Schwarzenegger?
– A world champion body
builder that became an actor
and governor of California.
– He used weight lifting to build
his muscles.
http://www.charlesatlas.com/
http://healthruns.com
Aerobic Exercise
Moderately intense exercise that improves the
heart and lungs
• Can you run four laps around the
track (~ 1 mile)?
• Common adult standard of
fitness: run 1.5 miles in 12
minutes.
• Running long distances several
times every week is probably a
bad idea (too hard on growing
joints).
– Use low-impact equivalents:
cycling, swimming, stair climbing,
cross-country skiing, ice skating.
A Balanced Exercise Program
• Running, cycling, or
swimming: both sprints
and long distance
• Body building: weight
lifting and isometrics
• Intersperse with rest
–Example: cycle every
other day, do bodybuilding exercises on
the other days.
Ruth Fremson/The New York Times
To Keep You on Track
Keep Track of Your Food and Exercise
• Make a plan (decide the kinds of exercise)
• Set goals (such as certain number of
minutes/day)
• Mix two or more kinds of exercise during each
week
• Keep track. Use this on-line exercise calendar.
Keep a Food Journal
• It can be very helpful to keep a written record of the food
you eat each day.
• There are many resources to help you keep track of your
daily food choices.
Examples:
•http://www.livestrong.com/myplate/
•http://www.my-calorie-counter.com/
•http://www.nhlbi.nih.gov/health/public/
heart/obesity/lose_wt/diary.htm
•http://www.personal-nutritionguide.com/food-diary-template.html
Conclude:
• Name 5 different types of
exercise.
• What are the two types of
exercises that should be
included in a balanced exercise
program?
• What is a food journal?
• What is one thing from this
lesson that is important to you?