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from the website: howstuffworks.com
How Exercise Works
by Craig C. Freudenrich, Ph.D.
When you exercise or compete in sports, you notice several things about your body. You breathe heavier & faster,
your heart beats faster, your muscles hurt & you sweat.
These are all normal responses to exercise whether you work out regularly
or only once in a while or whether you're a "weekend warrior" or a trained athlete.
When you watch world-class
athletes compete, you see the same responses, only magnified.
The body has an incredibly
complex set of processes to meet the demands of working muscles. Every system in the body is involved. We'll look at
how your body responds to strenuous exercise, how:
- muscles
- blood circulation
- breathing
- body heat
are affected. You'll also see how these responses can be enhanced
by training.
  Your Body's Response
to Exercise
Any type of exercise uses your muscles. Running, swimming, weightlifting; any sport you can imagine uses different muscle groups to generate motion.
In running & swimming, your muscles are working to accelerate your body &
keep it moving. In weightlifting, your muscles are working to
move a weight. Exercise means
muscle activity!
As you use your muscles, they
begin to make demands on the rest of the body. In strenuous exercise, just about every system
in your body either focuses its efforts on helping the muscles do their work, or it shuts down.
e.g., your
heart beats faster during strenuous exercise so that it can pump more blood to the muscles
& your stomach shuts down during strenuous exercise so that it doesn't waste energy
that the muscles can use.
When you exercise,
your muscles act something like electric motors. Your muscles take in a source of energy & they use it to generate
force. An electric motor uses electricity to supply its energy. Your muscles are biochemical motors & they use a chemical
called adenosine triphosphate (ATP) for their energy source.
During the process
of "burning" ATP, your muscles need 3 things:
- They need oxygen, because chemical reactions require ATP & oxygen is consumed to produce ATP.
- They need to eliminate metabolic wastes (carbon dioxide, lactic acid) that the chemical reactions
generate.
- They need to get rid of heat. Just like an electric motor, a working muscle generates heat that it needs to get rid of.
In order to continue exercising,
your muscles must continuously make ATP. To make this happen, your body must supply oxygen to the muscles & eliminate
the waste products & heat.
The more strenuous
the exercise, the greater the demands of working muscle. If these needs aren't met, then exercise will cease, that is, you become exhausted & you won't be
able to keep going.
To meet the needs of working muscle, the body has an orchestrated response involving the heart, blood vessels, nervous system, lungs,
liver & skin. It really is an amazing system!
Let's examine each need & how it's met by the various systems of the body.
ATP is Energy!
For your muscles
in fact, for every cell in your body - the source of energy that keeps everything going is called ATP.
Adenosine triphosphate (ATP) is the biochemical way to store & use energy.
The entire reaction that turns
ATP into energy is a bit complicated, but here's a good summary:
- Chemically, ATP is an adenine nucleotide bound to 3 phosphates.
- There's a lot of energy stored
in the bond between the 2nd & 3rd phosphate groups that can be used to fuel chemical reactions.
- When a cell needs energy, it breaks this bond to form adenosine diphosphate (ADP)
& a free phosphate molecule.
- In some instances, the 2nd
phosphate group can also be broken to form adenosine monophosphate (AMP).
- When the cell has excess
energy, it stores this energy by forming ATP from ADP
& phosphate.
ATP is required for
the biochemical reactions involved in any muscle contraction. As the work of the muscle increases, more & more ATP gets consumed & must be replaced in order for the muscle to keep moving.
Because ATP is so important, the body has several different systems to create ATP.
These systems work together in phases. The interesting thing is that different forms of exercise
use different systems, so a sprinter is getting ATP in a completely different way from a
marathon runner!
ATP comes from 3 different
biochemical systems in the muscle, in this order:
- phosphagen system
- glycogen-lactic acid system
- aerobic respiration
Now, let's look at each one in detail.
Phosphagen System
A muscle cell has some amount of ATP floating around that it can use immediately,
but not very much, only enough to last for about 3 seconds.
To replenish the ATP levels quickly, muscle cells contain a high-energy phosphate compound called creatine phosphate. The phosphate group is removed from creatine phosphate by an enzyme
called creatine kinase & is transferred to ADP to form ATP.
The cell turns ATP into
ADP & the phosphagen rapidly turns the ADP back into ATP. As the muscle continues to work, the creatine phosphate levels
begin to decrease. Together, the ATP levels & creatine phosphate levels are called the phosphagen system.
The phosphagen system
can supply the energy needs of working muscle at a high rate, but only for 8 to 10 seconds.
Glycogen-Lactic Acid System
Muscles
also have big reserves of a complex carbohydrate
called glycogen. Glycogen is a chain of glucose molecules.
A cell splits glycogen into glucose. Then the cell uses anaerobic metabolism (anaerobic means "without oxygen") to make ATP & a byproduct
called lactic acid from the glucose.
About 12 chemical reactions
take place to make ATP under this process, so it supplies ATP
at a slower rate than the phosphagen system. The system can still act rapidly & produce enough ATP
to last about 90 seconds.
This system doesn't need oxygen, which is handy because it takes the heart & lungs some time to get their act together. It's also handy because the
rapidly contracting muscle squeezes off its own blood vessels, depriving itself of oxygen-rich blood.
Why Should I Be Active?
From the Centers for Disease Control & Prevention (CDC),
Updated March 3,
2003
"It's easier to maintain
your health than regain it."
Dr.
Ken Cooper
Physical activity
can bring you many health benefits. People who enjoy participating in moderate-intensity or vigorous-intensity physical activity
on a regular basis benefit by lowering their risk of developing coronary heart disease, stroke, non-insulin dependent (type 2) diabetes mellitus, high blood pressure & colon cancer by 30-50% (USDHHS, 1996).
Additionally,
active people have lower premature death rates than people who are the least active.
Regular
physical activity can improve health & reduce the risk of premature death in the following ways:
- Reduces the risk of
developing coronary heart disease (CHD) & the risk of dying from CHD
- Reduces the risk of stroke
- Reduces the risk of
having a 2nd heart attack in people who've already had 1 heart attack
- Lowers both total blood
cholesterol & triglycerides & increases high-density lipoproteins (HDL or the "good" cholesterol)
- Lowers the risk of
developing high blood pressure
- Helps reduce blood
pressure in people who already have hypertension
- Lowers the risk of
developing non-insulin-dependent (type 2) diabetes mellitus
- Reduces the risk of
developing colon cancer
- Helps people achieve
& maintain a healthy body weight
- Reduces feelings of depression & anxiety
- Promotes psychological
well-being & reduces feelings of stress
- Helps build & maintain
healthy bones, muscles & joints
- Helps older adults become
stronger & better able to move about without falling or becoming excessively fatigued
Making Physical Activity
Part of Your Life
From the Centers for Disease Control & Prevention (CDC)
Updated February 6, 2003
"You can't change where you came from. You can change where you are going."
Anonymous
Just knowing that physical activity is good for
us doesn't mean that we'll be able to make it part of our daily routines, it's sometimes difficult to adopt new habits. But
it's important to remember that you can start out slowly & work your way up to a higher level of activity.
This section
provides ideas for how to make physical activity part of your life & how to do it safely.
What Are Some Tips for Being More Active?
There are 1440 minutes in every day... Schedule 30 of them for physical activity.
Adults need recess too! With a little creativity & planning, even the person with the busiest schedule can make room for physical
activity. For many folks, before or after work or meals is often an available time to cycle, walk, or play.
Think about your weekly or daily schedule & look for or make opportunities to
be more active. Every little bit helps. Consider the following suggestions:
- Walk, cycle, jog, skate, etc., to work, school, store, or place of worship.
- Park the car farther away
from your destination.
- Get on or off the bus several
blocks away.
- Take the stairs instead of
the elevator or escalator.
- Play with children or pets.
Everybody wins. If you find it too difficult
to be active after work, try it before work.
- Take fitness breaks-walking
or doing desk exercises - instead of taking cigarette or coffee breaks.
- Avoid labor-saving devices-turn
off the self-propel option on your lawn mower or vacuum cleaner.
- Use leg power-take small
trips on foot to get your body moving.
- Exercise while watching TV
(i.e., use hand weights, stationary bicycle / treadmill / stairclimber or stretch).
- Keep a pair of comfortable
walking or running shoes in your car & office. You'll be ready for activity wherever you go!
- Make a Saturday morning walk
a group habit.
- Walk while doing errands.
click the underlined title below to read the article
on Healthscout!
Starting Exercise Means a Medical 'Tune-Up' First: See your doctor before embarking on any new summer
regimen, experts advise
Tips for People Who've Been Inactive for a While
Use a sensible approach
by starting out slowly.
- Begin by choosing moderate-intensity
activities you enjoy the most. By choosing activities you enjoy, you'll be more likely to stick with them.
- Gradually build up the time
spent doing the activity by adding a few minutes every few days or so until you can comfortably perform a minimum recommended amount of activity (30 minutes per day).
- As the minimum amount becomes
easier, gradually increase either the length of time performing an activity or increase the intensity of the activity, or
both.
- Vary your activities, both
for interest & to broaden the range of benefits.
- Explore new physical activities.
Are There Risks To Being Active?
"All of
life is the management of risk, not elimination."
Walter Wriston
Although there can be some
risks associated with physical activity, most can be avoided or minimized by taking reasonable
precautions.
Cardiovascular Risks
Occasionally, we learn about
an athlete who died suddenly while jogging or exercising strenuously. These athletes typically
had underlying cardiovascular disease that, when coupled with extremely strenuous activity, resulted in their death. Such
events can plant doubts & fears in the minds of people who are thinking about leading a more active lifestyle.
"Me? Exercise & end up having a heart attack?
No way!"
However, sudden deaths due to underlying cardiovascular disease are extremely rare,
particularly among individuals participating in moderate-intensity physical activity (Pratt, 1995).
Persons with known
cardiovascular disease or persons who have already experienced a major cardiovascular event, such as a heart attack, stroke,
or heart surgery, should have a physical evaluation by their physician before engaging in even a moderate physical activity
program.
But other than in those cases, most adults don't need to consult their physicians before engaging in moderate-intensity physical activity. If, however, they're planning to engage
in vigorous-intensity physical activity, experts recommend that men over age 40 & women over age 50 should also consult
a physician first.
Other Risks
The most common risk associated with
physical activity is injury to the musculoskeletal system-the bones, joints, tendons & muscles. These injuries are usually
not serious, often require no treatment other than a few days of rest & can be minimized by taking sensible precautions.
Most of these types
of injuries related to physical activity may be prevented by gradually working up to the desired level of activity & by avoiding excessive amounts of activity at one time.
Therefore, to avoid
soreness & injury, people who haven't been regularly active & are thinking about increasing their levels of physical
activity should start out slowly, incorporating even a few minutes of increased activity into their day, gradually building
up to the desired amount of activity & giving their bodies time to adjust (Pate et al., 1995).
What Are Some Tips for Avoiding Activity-Induced Injuries?
"Success doesn't come to you... You go to it."
Marva Collins
Keeping the following tips in mind can help prevent common injuries associated
with participating in physical activity.
- Listen to your body-monitor
your level of fatigue, heart rate & physical discomfort.
- Be aware of the signs of
overexertion. Breathlessness & muscle soreness could be danger signs.
- Be aware of the warning signs & signals of a heart attack, such as sweating, chest & arm pain, dizziness & lightheadedness.
- Use appropriate equipment
& clothing for the activity.
- Take 3-5 minutes at the beginning
of any physical activity to properly warm up your muscles thru increasingly more intense activity.
As you near the end of the
activity, cool down by decreasing the level of intensity. (i.e., before jogging, walk for 3-5 minutes
increasing your pace to a brisk walk. After jogging, walk briskly, decreasing your pace to a slow walk over 3-5 minutes. Finish
by stretching the muscles you used-in this case primarily the muscles of the legs.)
- Start at an easy pace-increase
time or distance gradually.
- Drink plenty of water throughout
the day to replace lost fluids (i.e., at least 8 to 10 - 8-oz. cups per day). Drink
a glass of water before you get moving, & drink another half cup every 15 minutes that you remain active.
How can I overcome barriers to physical activity?
"If
you can find a path with no obstacles, it probably doesn't lead anywhere."
Anonymous
Given the health benefits
of regular physical activity, we might have to ask why 2 out of 3 (60%) Americans are not
active at recommended levels. There are barriers that keep Americans from being, or becoming, regularly physically active.
Understanding common barriers
to physical activity & creating strategies to overcome them may help you make physical activity part of your daily life.
Environmental Barriers
Social environments such as school, work, family & friends can significantly influence an individual's level
of physical activity.
However, characteristics of our communities such as the accessibility & location of parks, trails, sidewalks
& recreational centers as well as street design, density of housing & availability of public transit may play &
even greater role in promoting or discouraging an individual or family's level of physical activity.
There are also significant
environmental barriers from water & air pollution to crime & dangerous automobile traffic.
To address this, the Centers for Disease Control & Prevention has initiated the ACES: Active Community Environments
Initiative project to promote & support the awareness & development of places where people of all ages & abilities
can easily enjoy walking, bicycling & other forms of
recreation.
There are many opportunities
with in our environment that support physical activities from parks, trails & sidewalks to recreation & fitness centers.
Even malls provide opportunities for fitness walking.
Understanding environmental
opportunities & barriers that we face in our pursuit for a healthy lifestyle may provide some of the knowledge necessary
to promote healthy living. This information may also provide ideas for advocacy & civic participation.
For more information on the Active Community Environments Initiative
& how you can support a positive environment for physical activity in your
community, please visit http://www.cdc.gov/nccdphp/dnpa/
aces.htm.
Personal Barriers
Aside from the many technological advances & conveniences that have made our lives easier & less active,
many personal variables, including physiological, behavioral & psychological factors, may affect our plans to become more
physically active.
In fact, the 10 most common
reasons adults cite for not adopting more physically active lifestyles are (Sallis &
Hovell, 1990; Sallis et al., 1992)
- Don't have enough time to exercise
- Find it inconvenient to exercise
- Don't find exercise enjoyable
- Lack confidence in their
ability to be physically active (low self-efficacy)
- Fear being injured or have
been injured recently
- Lack self-management skills,
such as the ability to set personal goals, monitor progress, or reward progress toward such goals
- Lack encouragement, support,
or companionship from family & friends
- Don't have parks, sidewalks,
bicycle trails, or safe & pleasant walking paths convenient to their homes or offices.
How can I figure out which barriers affect me most?
The "Barriers to Being Active Quiz" can help you identify the types of physical activity barriers
that are undermining your ability to make regular physical activity & integral part of your life.
The quiz calculates a score in each of 7 barrier categories. Once you've taken the quiz & identified which
barriers affect you the most, look at the table below for suggestions on how to overcome them.
Suggestions for Overcoming Physical Activity Barriers
Lack of time
- Identify available time slots.
- Monitor your daily activities
for one week.
- Identify at least 3 30-minute
time slots you could use for physical activity.
- Add physical activity to
your daily routine, e.g.,
- walk or ride your bike to work or shopping
- organize school activities around physical activity
- exercise while you watch
TV
- park farther away from your destination, etc.
- Make time for physical activity, e.g.,
- swim during your lunch hour
- take fitness breaks instead of coffee breaks.
- Select activities requiring minimal time, such as walking,
jogging, or stairclimbing.
Social influence
- Explain your interest in physical activity to friends &
family. Ask them to support your efforts.
- Invite friends & family members to
exercise with you. Plan social activities involving exercise.
- Develop new friendships with physically
active people. Join a group, such as the YMCA or a hiking club.
Lack of energy
- Schedule physical activity
for times in the day or week when you feel energetic.
- Convince yourself that if you give it a chance, physical activity
will increase your energy level; then, try it.
Lack of Motivation
- Plan ahead. Make physical activity
a regular part of your daily or weekly schedule & write it on your calendar.
- Invite a friend to exercise w/you on a
regular basis & write it on both your calendars.
- Join an exercise group or class.
Fear of Injury
- Learn how to warm up & cool down to prevent injury.
Learn how to exercise appropriately
considering your age, fitness level, skill level & health status.
- Choose activities involving minimum risk.
Lack of Skill
- Select activities requiring no new skills, such as walking,
climbing stairs, or jogging.
- Exercise with friends who are at the same skill level as you
are.
- Find a friend who is willing to teach you
some new skills.
- Take a class to develop new skills.
Lack of Resources
- Select activities that require minimal facilities or equipment,
such as walking, jogging, jumping rope, or calisthenics.
- Identify inexpensive, convenient resources available
in your community (community education programs, park & recreation programs, worksite programs,
etc.).
Weather conditions
- Develop a set of regular
activities that are always available regardless of weather (indoor cycling, aerobic dance, indoor swimming, calisthenics, stair climbing, rope skipping, mall walking, dancing, gymnasium games, etc.)
- Look on outdoor activities that depend on weather conditions (cross-country skiing, outdoor swimming, outdoor tennis, etc.) as "bonuses"- extra activities possible when weather & circumstances permit.
Travel
- Put a
jump rope in your suitcase & jump rope.
- Walk the halls & climb the stairs in hotels.
- Stay
in places with swimming pools or exercise facilities.
- Join
the YMCA or YWCA (ask about reciprocal membership agreement).
- Visit
the local shopping mall & walk for half an hour or more.
Family obligations
- Trade babysitting time with a friend, neighbor, or family member who also has small children.
- Exercise with
the kids - go for a walk together, play tag or other running games, get an aerobic dance or exercise tape for kids (there are several on the market)
& exercise together. You can spend time together & still
get your exercise.
- Hire a babysitter &
look at the cost as a worthwhile investment in your physical & mental health.
- Jump rope,
do calisthenics, ride a stationary bicycle, or use other home gymnasium equipment while the kids are busy playing or sleeping.
Try to
exercise when the kids aren't around (e.g., during school
hours or their nap time).
- Encourage exercise facilities to provide child care services.
Retirement years
Look upon
your retirement as an opportunity to become more active instead
of less.
Spend more time:
- playing with your grandchildren
Children with short legs & grandparents with slower gaits are often great walking partners.
Learn a new skill you've always been interested in, such as ballroom
dancing, square dancing, or swimming.
Now that you have the time, make regular physical activity
a part of every day. Go for a walk every morning or every evening before dinner. Treat yourself to an exercycle & ride every day while reading a favorite
book or magazine.
Content in the "Personal
Barriers" section was taken from Promoting Physical Activity: A Guide for Community Action (USDHHS, 1999).
Creating
a Personalized Fitness Program
--From the President's Council on Physical Fitness and Sports (PCPFS),
Reviewed
December 2002
Making a Commitment
You've taken the important 1st step on
the path to physical fitness by seeking information. The next step is to decide that you're going to be physically fit. This
information is designed to help you reach that decision & your goal.
The decision to carry out a physical fitness
program can't be taken lightly. It requires a lifelong commitment of time & effort. Exercise must become one of those
things that you do without question, like bathing & brushing your teeth.
Unless you are convinced of the benefits of
fitness & the risks of unfitness, you will not succeed.
Patience is essential. Don't try to do too much too soon
& don't quit before you have a chance to experience the rewards of improved fitness. You can't regain in a few days or
weeks what you have lost in years of sedentary living, but you can get it back if your persevere. And the prize is worth the
price.
In the following pages you will find the basic information you need to begin and maintain a personal physical
fitness program. These guidelines are intended for the average healthy adult. It tells you what your goals should be &
how often, how long & how hard you must exercise to achieve them.
It also includes information that will make
your workouts easier, safer & more satisfying. The rest is up to you.
Checking Your Health
If you're under 35 & in good health, you don't need to see a doctor before beginning an exercise program. But if
you are over 35 & have been inactive for several years, you should consult your physician, who may or may not recommend
a graded exercise test.
Other conditions that indicate
a need for medical clearance are:
- High blood pressure.
-
Heart trouble.
-
Family history of early stroke or heart attack
deaths.
-
Frequent dizzy spells.
-
Extreme breathlessness after mild exertion.
-
Arthritis or other bone problems.
-
Severe muscular, ligament or tendon problems.
-
Other known or suspected disease.
Vigorous
exercise involves minimal health risks for persons in good health or those following a doctor's
advice. Far greater risks are presented by habitual inactivity & obesity.
Defining Fitness
Physical fitness is to the human body what fine tuning is to an engine. It enables us to perform up to our potential.
Fitness can be described as a condition that helps us look, feel & do our best.
More specifically,
it is:
"The ability to perform daily tasks vigorously & alertly, with energy left over for enjoying leisure
time activities & meeting emergency demands. It's the ability to endure, to bear up, to withstand stress, to carry on in circumstances where an unfit person couldn't continue & is a major basis for good health & well-being."
Physical fitness
involves the performance of the heart & lungs & the muscles of the body. Since what we do with our bodies also
affects what we can do with our minds, fitness influences to some degree qualities such as mental alertness & emotional
stability.
As you undertake your fitness program, it's important to remember that fitness is an individual quality that varies from person to person.
It's influenced by:
-
age
-
sex
-
heredity
-
personal habits
-
exercise
-
You can't do anything about the first 3 factors. However, it's within your power to change & improve the others where needed.
Knowing the Basics
Physical fitness is most easily understood by examining its components, or "parts."
There's widespread agreement
that these 4 components are basic:
- Cardiorespiratory Endurance - the ability to deliver oxygen & nutrients to tissues & to remove wastes, over sustained periods
of time. Long runs & swims are among the methods employed in measuring this component.
-
Muscular Strength - the ability of a muscle to exert force for a brief period
of time. Upper-body strength, i.e., can be measured by various weight-lifting exercises.
-
Muscular Endurance - the ability of a muscle, or a group of muscles, to sustain repeated contractions or to continue applying force against a fixed object. Pushups are often used to test endurance of arm &
shoulder muscles.
-
Flexibility - the ability to move joints & use muscles thru
their full range of motion. The "sit & reach" test is a good measure of flexibility of the lower back & backs of the
upper legs.
BODY COMPOSITION is often considered a component of fitness. It refers to the makeup of the body in terms of lean mass
(muscle, bone, vital tissue & organs) & fat mass.
An optimal
ratio of fat to lean mass is an indication of fitness & the right types of exercises
will help you decrease body fat & increase or maintain muscle mass.
A Workout Schedule
How often, how long & how hard
you exercise & what kinds of exercises you do
should be determined by what you're trying
to accomplish.
are among the factors you should consider.
i.e.,
an athlete training for high-level competition would follow a different program than a person whose goals are good health & the ability to meet work & recreational needs.
Your exercise
program should include something from each of the 4 basic fitness components described
previously.
Each workout should begin with a warmup &
end with a cooldown. As a general rule, space your workouts throughout the week & avoid consecutive days of hard exercise.
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How Muscles Work
Muscles are one of those things that most of us take completely for
granted, but they're incredibly important for 2 key reasons:
- Muscles are the "engine"
that your body uses to propel itself. Although they work differently than a car engine or an electric motor,
muscles do the same thing; they turn energy into motion.
- It would be impossible
for you to do anything without your muscles. Absolutely everything that you conceive of with your brain is expressed as muscular
motion.
The only ways for you
to express an idea are with the muscles of your larynx, mouth & tongue (spoken words),
with the muscles of your fingers (written words or "talking with your hands") or with the
skeletal muscles (body language, dancing, running, building or fighting, to name a few).
Because muscles
are so crucial to any animal, they're incredibly sophisticated. They're efficient at turning fuel into motion, long-lasting, self-healing
& they're able to grow stronger with practice. They do everything from allowing you to walk to keeping your blood flowing!
Let's look at the
different types of muscles in your body & the amazing technology that allows them to work so well.
Types of Muscle
When most people think of "muscles," they think about
the muscles that we can see.
e.g., most of us know about the
biceps muscles in our arms. But there are 3 unique kinds of muscle in any mammal's body:
-
Skeletal muscle is the type of muscle that we can see & feel. When a body builder
works out to increase muscle mass, skeletal muscle is
what is being exercised. Skeletal muscles attach to the skeleton & come in pairs: one muscle to move the bone in one direction & another to move it back the other way. These
muscles usually contract voluntarily, meaning that you think about contracting them & your nervous system tells them to
do so. They can do a short, single contraction (twitch) or a long, sustained contraction (tetanus).
- Smooth muscle is found in your digestive
system, blood vessels, bladder, airways
& in a female, the uterus. Smooth
muscle has the ability to stretch & maintain tension for long periods of time. It contracts involuntarily, meaning that
you don't have to think about contracting it because your nervous system controls it automatically.
e.g., your stomach & intestines do their
muscular thing all day long & for the most part, you never know what's going on in there.
- Cardiac muscle is found only in your heart
& its big features are endurance & consistency.
It can stretch in a limited way, like smooth muscle & contract w/the force of a skeletal muscle. It is a twitch muscle
only & contracts involuntarily.
Next we'll focus on skeletal muscle. The basic
molecular processes are the same in all 3 types.
Ideas for Active Family Fun
From the Centers for Disease Control & Prevention (CDC)
Updated February 6, 2003
Healthy Kids. Healthy Families.
Physical Activity Can Make
the Connection
It's worth it.
Physical
activity builds a great foundation for a healthy life. It's a win/win event for you & your child. Physical activity can:
Increase self-esteem & capacity for learning.
Help kids handle stress.
Build & maintain healthy bones, muscles
& joints.
Help control weight.
Experience active family fun.
Create family traditions & lasting memories.
Time together is time
that's treasured. Try:
Family Adventures
See the sights of your community. Try hiking, fishing, canoeing, &
berry-picking. Discover the public parks. Visit the zoo. Explore outdoor tourist attractions.
Family Fitness Vacations
Plan an active get-away. Swim at the beach or bike on a scenic trail. Hike or camp in the mountains. Explore state &
national parks. Raft down a river. Take a walking tour of a city.
The Gift of Physical Activity
Give a present
that encourages activity. Outfit that special someone w/a swimsuit or pair of athletic shoes. Select toys that make you move,
such as a basketball or bicycle.
Seasonal Celebrations
Welcome each one w/fun.
Winter: Go sledding or build
a snowman.
Spring: Play whiffle ball or fly a kite.
Summer: Run through the sprinkler or jump rope.
Fall: Play
Frisbee golf or hike through a pumpkin patch.
Community Service
Benefit others while benefiting yourself volunteer
as a family. Do litter patrol on a nearby road, help neighbors rake their yard or team up to clean up a favorite park.
Find
the right fit.
Organized activities, such as lessons, clubs and teams, can be a positive experience if they match your
child's interests & personality. Before signing up, check out the program & answer the following questions. A majority
of "yes" answers suggests enjoyment for your child.
Does my child's skill level & size match the rest of the group?
Are the challenges & expectations appropriate for my child?
Are all children given meaningful opportunities to learn skills & participate fully?
Is there a focus on development of fair play, teamwork, sportsmanship & having fun?
Does the activity leader provide encouragement & positive feedback?
Are all children treated w/respect?
It's not just an action, it's a lifestyle.
Walk & Talk Instead of sitting at the table to do homework,
take a walk w/your child while practicing spelling words, multiplication tables or geography facts.
Household Jobs
Encourage responsibility & home maintenance skills by having your children help vacuum, scrub floors, mow
the lawn, walk the dog, wash the car & more.
Indoor Fun
Designate a space where kids can roll, climb, jump, dance & tumble. Garages - without cars - can become an
activity zone on rainy or snowy days.
Traveling Locker Room
Stash a box in the family car that holds balls, baseball gloves, a jump rope, Frisbee, kite, etc. You'll always
be ready for fun.
Experience the fun together.
Kids just need to play. And so do you.
Here are the amounts of activity necessary
for the average healthy person to maintain a minimum level of overall fitness. Included are some of the popular exercises
for each category.
WARMUP - 5-10 minutes of exercise such as walking, slow jogging,
knee lifts, arm circles or trunk rotations. Low intensity movements that simulate movements to be used in the activity can
also be included in the warmup.
MUSCULAR
STRENGTH - a minimum of two 20-minute sessions
per week that include exercises for all the major muscle groups. Lifting weights is the most effective way to increase strength.
MUSCULAR ENDURANCE - at least three 30-minute sessions each week that include exercises such as:
- calisthenics
- pushups
- situps
- pullups
- weight training for all the major muscle groups
CARDIORESPIRATORY ENDURANCE - at least 3 20-minute bouts of continuous aerobic (activity requiring
oxygen) rhythmic exercise each week.
Popular aerobic conditioning activities include:
- brisk walking
- jogging
- swimming
- cycling
- rope-jumping
- rowing
- cross-country skiing
- some continuous action games like racquetball
& handball
FLEXIBILITY - 10-12 minutes of daily stretching exercises performed slowly, without a bouncing motion. This can be included after a warmup or during a cooldown.
COOL DOWN - a minimum of 5-10 minutes of slow walking, low-level exercise, combined w/stretching.
A Matter of Principle
The keys to selecting the right kinds of exercises for
developing & maintaining each of the basic components of fitness are found in these principles:
SPECIFICITY - pick the right kind of activities to affect each component. Strength training results in specific strength
changes. Also, train for the specific activity you're interested in.
e.g., optimal swimming performance
is best achieved when the muscles involved in swimming are trained for the movements required. It does not necessarily follow
that a good runner is a good swimmer.
OVERLOAD
- work hard enough, at levels that are vigorous
& long enough to overload your body above its resting level, to bring about improvement.
REGULARITY - you can't hoard physical fitness. At least 3 balanced workouts a week are necessary to maintain a desirable
level of fitness.
PROGRESSION - increase the intensity, frequency &/or duration
of activity over periods of time in order to improve.
Some activities can be used to fulfill more than one of your
basic exercise requirements.
e.g., in addition to increasing cardiorespiratory
endurance, running builds muscular endurance in the legs & swimming develops the arm, shoulder & chest muscles.
If you select the proper activities,
it is possible to fit parts of your muscular endurance workout into your cardiorespiratory workout & save time.
Measuring Your Heart Rate
Heart rate is widely accepted as a good method for measuring intensity during running, swimming,
cycling & other aerobic activities. Exercise that doesn't raise your heart rate to a certain level & keep it there
for 20 minutes won't contribute significantly to cardiovascular fitness.
The heart rate you should maintain is called
your target heart rate. There are several ways of arriving at this figure. One of the simplest is: maximum heart rate (220
- age) x 70%. Thus, the target heart rate for a 40 year-old would be 126.
Some methods for figuring the target rate
take individual differences into consideration. Here is one of them:
Resting heart rate should be determined by
taking your pulse after sitting quietly for 5 minutes. When checking heart rate during a workout, take your pulse within 5
seconds after interrupting exercise because it starts to go down once you stop moving. Count pulse for 10 seconds & multiply by 6 to get the per-minute rate.
Controlling Your Weight
The key to weight control is keeping energy intake (food) & energy output (physical activity) in
balance. When you consume only as many calories as your body needs, your weight will usually remain constant. If you take
in more calories than your body needs, you will put on excess fat. If you expend more energy than you take in you will burn
excess fat.
Exercise plays an important role in weight control by increasing energy output, calling on stored calories
for extra fuel. Recent studies show that not only does exercise increase metabolism during a workout, but it causes your metabolism
to stay increased for a period of time after exercising, allowing you to burn more calories.
How much exercise is
needed to make a difference in your weight depends on the amount & type of activity & on how much you eat.
Aerobic exercise burns body fat. A medium-sized adult would have to walk more than 30 miles to burn
up 3,500 calories, the equivalent of one pound of fat.
Although that may seem like a lot, you don't have to walk the 30 miles all at once. Walking a
mile a day for 30 days will achieve the same result, providing you don't increase your food intake to negate the effects of
walking.
If you consume 100 calories a day more than your body needs, you will gain approximately 10 pounds in a year.
You could take that weight off, or keep it off, by doing 30 minutes of moderate exercise daily.
The combination of exercise & diet offers the most flexible & effective approach to
weight control.
Since muscle tissue weighs more than fat tissue & exercise develops muscle to a certain degree,
your bathroom scale won't necessarily tell you whether or not you're "fat."
Well-muscled individuals, w/relatively little
body fat, invariably are "overweight" according to standard weight charts. If you are doing a regular program of strength
training, your muscles will increase in weight & possibly your overall weight will increase.
Body composition is a better indicator of your condition than body weight.
Lack of physical
activity causes muscles to get soft & if food intake is not decreased, added body weight is almost always fat. Once-active
people, who continue to eat as they always have after settling into sedentary lifestyles, tend to suffer from "creeping obesity."
Clothing
All exercise clothing should be loose-fitting to permit freedom of movement & should make
the wearer feel comfortable & self-assured.
As a general rule, you should wear lighter clothes than temperatures
might indicate. Exercise generates great amounts of body heat. Light-colored clothing that reflects the sun's rays is cooler
in the summer & dark clothes are warmer in winter.
When the weather is very cold, it's better
to wear several layers of light clothing than 1 or 2 heavy layers. The extra layers help trap heat & it's easy to shed
one of them if you become too warm.
In cold weather & in hot, sunny weather, it's a good idea to wear something
on your head. Wool watch or ski caps are recommended for winter wear & some form of tennis or sailor's hat that provides
shade & can be soaked in water is good for summer.
Never wear rubberized or plastic clothing, such garments interfere
w/the evaporation of perspiration & can cause body temperature to rise to dangerous levels.
The most important
item of equipment for the runner is a pair of sturdy, properly-fitting running shoes. Training shoes w/heavy, cushioned soles
& arch supports are preferable to flimsy sneakers & light racing flats.
When To Exercise
The
hour just before the evening meal is a popular time for exercise. The late afternoon workout provides a welcome change of
pace at the end of the work day & helps dissolve the day's worries & tensions.
Another popular time to work
out is early morning, before the work day begins. Advocates of the early start say it makes them more alert & energetic
on the job.
Among the factors you should consider in developing your workout schedule are personal preference, job
& family responsibilities, availability of exercise facilities & weather. It's important to schedule your workouts
for a time when there is little chance that you will have to cancel or interrupt them because of other demands on your time.
You should not exercise strenuously during extremely hot, humid weather or within 2 hours after eating. Heat and/or
digestion both make heavy demands on the circulatory system, & in combination w/exercise can be an overtaxing double load.
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Working up a sweat isn't just good for
your body it's good for your brain. Here's why.by Claire Moore
5 Ways Exercise Helps your Head....
Everyone knows that exercise gets our blood
pumping, burns fat & calories & reduces the chances of developing heart disease & obesity, among other maladies.
But now a growing body of evidence suggests
that even as few as 10 minutes of activity a day can bolster your mental health & leave you thinking more clearly &
feeling happier & less stressed.
"People who exercise report feeling better in
general, even after just one workout," says Daniel M. Landers, professor of exercise & physical education at Arizona State
University.
Here, five ways that exercise revs up your state of mind.
- Exercise boosts brain power.
"We know that regular physical activity improves reaction time, concentration, creativity &
mental vigor," says Landers. Most likely, that's because it improves the body's ability to pump blood, which boosts the amount
of oxygen in the bloodstream & speeds up blood flow to the brain. Experts believe that all of these changes encourage quicker physical & mental reactions.
- Exercise helps fight aging.
In a recent study, researchers found that doing something as simple as walking on a regular basis
helps prevent mental slowdown in women over 65 & the longer & more often they walk, the greater the mental edge. Best
of all: Most people reap these stay-sharp benefits after just nine weeks of thrice-weekly workouts.
"The sessions don't have to be high intensity,"
says Landers. "It's enough to just move around & get your heart rate up."
- Exercise stops stress in its tracks. "Exercise can reduce anxiety & may even help you deal w/anger," says William P. Morgan,
Ed.D., director of the exercise psychology lab at the University of Wisconsin in Madison. The reason is simple: It's tough
to focus on unpaid bills & looming work deadlines when you're running your heart out on the treadmill. Aside from helping
you forget about that mile-long to-do list, regular aerobic exercise also boosts your cardiovascular fitness, which may actually
make you less likely to overreact to problems & able to recover more quickly from major life stressors. Rhythmic, repetitive aerobic activities, such as
walking, cycling, swimming
& jogging, are best for busting stress,
as are more obviously meditative pursuits, such as yoga.
- Exercise gives you a natural high. Whether you prefer your workouts short &
intense or long & leisurely, exercise can boost levels of feel-good chemicals in the brain, such as adrenaline, serotonin, dopamine & endorphins, the body's natural painkillers. (How else could a marathoner run 26.2 miles & have fun
doing it?) A study conducted in England found that 83% of people w/mental health problems relied on exercise to improve their
mood & reduce anxiety. "For people w/mild or moderate
depression, we now know that exercising over a period of at least 16 weeks can have the same mood-boosting effects as prescription
antidepressants such as Zoloft & Prozac," says Landers.
Researchers at Duke University found that 60%
of people suffering from depression for 4 months who worked out for 30 minutes 3 times a week were able to overcome the blues
w/out using any medication.
One possible
reason for the activity-induced boost:
Exercisers seem to spend less time in the REM phase
of sleep, a period during which the body stops producing serotonin, the depression-fighting brain chemical, explains Shawn
Youngstedt, assistant project scientist at the University of California at San Diego. But whatever the physiological reason,
exercise is definitely a powerful drug. "This doesn't mean people should just stop taking their medication, especially if
they have severe depression," cautions Dr. Morgan. But many psychologists are now writing a prescription for three weekly
dates at the gym, along with the latest blues-busting medication.
and
#5. Exercise boosts self-esteem. It stands to reason that getting stronger, leaner & more adept at an activity can have a positive impact
on self-esteem.
Indeed, one recent study found that teenagers who are
active in sports have a greater sense of well-being than their sedentary peers. There's a fine line, though, between committing
to regular workouts & obsessing about getting to the gym.
"The stress should be on achieving a healthy body image"
& improving your fitness level, says Landers, not on looking like some scrawny model on the cover of a fashion magazine.
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