© 2007 thomson - wadsworth chapter 10 nutrition and fitness

© 2007 Thomson - Wadsworth

Chapter 10

Nutrition and Fitness


Ask Yourself1. Regular exercise can help people increase their

lean body mass and reduce their fat tissue.2. Less than 25% of U.S. adults exercise adequately.3. People who fail to exercise regularly are more

likely to fall prey to degenerative diseases such as heart disease, osteoporosis, and diabetes.

4. Essentially, to be fit means to be at desirable weight and to have strong muscles.

5. People should never push themselves to exercise longer or harder than they can easily manage to do.


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.


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:StrengthFlexibilityMuscle enduranceCardiovascular

endurance

Fitness, like good nutrition,is an essential componentof good health.


Benefits of Physical Activity

• Increased self-confidence

• 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


Lifetime Fitness


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.


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.


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.


Components of FitnessPhysical 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.


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.


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 long-lasting, 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.


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.


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.


Yesterday’s Genes, Today’s Lifestyle

• Nearly all of your biochemistry and physiology was fine-tuned 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


• Preagricultural hunter-gatherers Burned ~3000

calories/day Moderate physical

activity >30 min/day Feast or famine Lean wild game or

fish Uncultivated fruits &

vegetables

• Industrialized modern humans Burn ~1800

calories/day Sedentary Abundance of food Grain-fattened meats Refined sugar


Choose Your Weapon……against the life-

threatening diseases associated with sedentary aging

• There is a need for physical activity throughout life.

Choose Your Weapon


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.

Make exercise a habit. Choose an activity you enjoy.


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 energy-producing systems: Aerobic: requiring

oxygen. Anaerobic: not

requiring oxygen.


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.


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.


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.


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.


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.


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; & high-carbohydrate diet = 83% carbohydrate.


Protein Needs for Fitness


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.



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.


Vitamins & Minerals for Exercise

Vitamins• Vitamins are the links and

regulators of energy-producing and muscle-building 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.


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.


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.


• 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…

Planning the Diet


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 higher-fat foods.

• Include plenty of fluids.• Any meal should be

finished a good 2 to 4 hours before the event…

The Pregame Meal


Sample Breakfasts


Athletes and Supplements—Help or Hype?

• Ergogenic aids: anything that helps to increase the capacity to work or exercise.ergo = workgenic = give rise to


Ergogenic aids: anything that helps to increasethe capacity to work or exercise.

ergo = workgenic = 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.


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.


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 chapter 10 nutrition and fitness

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