Nutrition and Exercise

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Chapter 14

• Nutrition and Exercise

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I. Fitness

• A. Defined
• 1. Characteristics that enable the body to
  perform physical activity
• 2. Ability to meet normal physical demands
  with enough reserves to meet sudden challenges
• 3. The bodies ability to withstand stress
• 4. Fitness depends on routine physical
  activity

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Fitness (cont)

• 5. Lack of Fitness
• a. 60 of U.S. not fit
• b. Obesity in children and adults is
  increasing
• B. Fitness and Its Benefits
• 1. Sleep
• 2. Nutrition
• 3. body composition
• 4. resistance to infection
• 5. lower risk of some cancers

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Fitness and Its Benefits (cont)

• 6. low risk of diabetes
• 7. lower risk of cardiovascular disease
  (CVD)
• 8. lower incidence if anxiety and depression
• 9. optimal bone density
• 10. longer life and better quality life in
  later years

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Fitness (cont)

• C. Components of Fitness
• 1. Flexibility
• 2. muscle strength
• 3. muscle endurance
• D. Conditioning by Training
• 1. progressive overload principle
• a. increased intensity
• b. increased duration
• c. increased frequency

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Progressive overload principle (cont)

• 2. Applying principle a. Be active all
  week b. Use proper equipment c. Warm-up and
  cool-down d. Challenge yourself
• 3. Cautions on Starting
• a. Be aware of your condition
• b. Seek medical advice if not
• 4. Bodys response to activity
• a. Muscle size increases (hypertrophy)

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Progressive overload principle (cont)

• 5. Types of muscle fibers
• a. set by heredity
• b. fast-twitch fibers and anaerobic work
• 1. no oxygen needed
• 2. glycogen -- glucose -- lactic acid
• 3. high-intensity, short-duration exercise
• c. slow-twitch muscles and aerobic work
• 1. oxygen needed
• 2. fatty acids oxygen -- energy (ATP)
• 3. low-intensity, long-duration exercise

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Fitness (cont)

• E. Cardiorespiratory (CR) Endurance
• 1. Length of time a person can remain active
  at an increased heart rate
• 2. CR Training requires oxygen (aerobic)
• 3. Benefits of aerobic training CR
• a. increased blood volume and oxygen delivery
• b. increased heart strength (stroke volume)
• c. slows resting pulse rate
• d. increases breathing efficiency
• e. improves circulation
• f. reduces blood pressure

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Cardiorespiratory System
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Cardiorespiratory (CR) Endurance (cont)

• 4. Benefits of aerobic training muscle
  conditioning
• a. muscles use oxygen more efficiently thus
  less is required
• b. capable of burning fat longer
• 5. Benefits of anaerobic training muscle
  strength and endurance
• a. develops muscles, bulking
• b. no CR benefits

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Cardiorespiratory (CR) Endurance (cont)

• 6. Balanced program (Table 14-2)
• a. flexibility
• b. muscle strength and endurance
• c. aerobic activity
• d. nutritious diet
• 7. A safe, balanced fitness program
• a. include warm-up and cool-down exercises
• b. slow and steady progress
• c. notice body symptoms of problems
• d. be active throughout the week
• e. use proper equipment and attire

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F. Female Athletic Triad eating disorders,
amenorrhea, osteoporosis

• 1. Caused by restricting food intake to
  improve performance
• a. Anorexia, bulimia, and bingeing
• b. weight-height charts not appropriate for
  athletes
• 2. Amenorrhea
• a. Prevalence in US women 2-5, athletes 66
• b. Characterized by low estrogen, infertility
  and osteoporosis
• c. associated with strenuous activity and low
  body fat

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Female Athletic Triad (cont)

• 3. Osteoporosis
• a. Usually occurs in elderly
• b. Many amenorrheic athletes have osteoporosis

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Female Athletic Triad
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II. Energy Systems, Fuels and Nutrients to
Support Activity

• A. Energy Systems for Physical Activity ATP
  PC
• 1. ATP (adenosine triphosphate)
• a. Energy from energy yielding nutrients
  stored in ATP (ADP P energy º ATP)
• b. provides energy for chemical reactions
  including muscular contraction
• c. ATP º ADP P energy

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Energy Systems for Physical Activity (cont)

• 2. PC (phosphocreatine)
• a. PC ADP º ATP
• b. provides energy for very short bursts of
  activity (20 seconds)
• c. Anaerobic
• 3. Energy-yielding nutrients
• a. glucose, amino acids and fat
• b. provide fuel for ongoing physical activity
• c. fat can only be used in aerobic metabolism

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Energy Systems for Physical Activity (cont)

• B. Glucose Use During Physical Activity
• 1. Diet affects storage of glycogen in
  liver and muscle cells
• a. depends on dietary carbohydrates
• b. glucose released at start of exercise
• c. anaerobic exercise

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Glucose Use During Physical Activity (cont)

• 2. Intensity of activity
• a. intense activity uses glycogen quickly
• b. moderate activity conserves glycogen
• c. lactic acid builds up with an increase in
  activity
• 1. Oxygen deficiency º anaerobic
  metabolism
• d. After 2 hours of strenuous activity
  glucose stores are depleted

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Cori Cycle

• Under anaerobic conditions glucose is converted
  to pyruvate but pyruvate in not able to enter the
  mitochondria due to oxygen deficiency.
  Consequently, pyruvate builds up and is converted
  to lactic acid. Lactic acid can decrease pH in
  the muscle so it must be removed. Lactic acid
  enters the blood and is taken up by the liver
  where it can converted to glucose. Glucose can
  then be used by muscle tissue.

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Glucose Use During Physical Activity (cont)

• 3. Duration of activity affects glycogen use
• a. during first 20 min. of moderate exercise
  use glycogen
• b. after 20 min. glycogen use 9 fat use 8
• c. eventually glycogen runs out and the liver
  makes glucose from lactic acid and amino acids
• d. maximize glucose reserves (glycogen)
• 1. eat high CHO diets
• 2. consume some glucose during event
• 3. training increases muscle storage of
  glycogen

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Glucose Use During Physical Activity (cont)

• 4. Glucose during activity
• a. Glycogen and CHO during activity
• b. What about insulin?
• 1. Epinephrine released during exercise
• 2. Epinephrine blocks insulin
• 5. Training affects glycogen use
• a. Ability of muscle to store glycogen 8
• b. Use fat more efficiency
• 1. increase in mitochondria
• a. Remember mitochondria require oxygen,
  so oxygen must be present to oxidize fat

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Energy Systems for Physical Activity (cont)

• C. Fat Use During Physical Activity
• 1. duration of activity affects fat use
• a. blood fatty acids used first
• b. stored triglycerides used second
• 2. intensity of activity affects fat use
• a. high intensity exercise uses less fat
• b. oxygen must be available

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Fat Use During Physical Activity (cont)

• 3. Training affects fat use
• a. repeated aerobic exercise
• 1. fat used more quickly at start
• 2. increases oxygen delivery
• 4. Recommendations
• a. Low to moderate activity for long duration
  (aerobic)

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Diet and Endurance
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Energy Systems for Physical Activity (cont)

• D. Protein use During Physical Activity
• 1. Protein used in muscle building
• a. Protein synthesis decreases during
  activity but increases afterwards
• 1. Net gain in protein (muscle)
• 2. Genetics limit amounts and types
• 2. Protein used as fuel
• a. Glucose is made from the amino acids in
  protein
• 1. Supplies 10 energy

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Protein use During Physical Activity (cont)

• 3. Diet affects protein use during activity
• a. Diets high in CHO spare protein
• 4. Recommended protein intake for active
  people (table 14-4)
• a. 1 gram per kilogram (1 g/kg) body weight
• 1. endurance athletes when training may
  need 1.5 g/kg body weight
• 2. power building athletes need 1.1 g/kg
• 3. in almost all case the typical American
  diet supplies these extra needs
• 4. supplements not needed

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Recommended Protein Intake for Athletes
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Nutrients to Support Activity

• E. Vitamins and Minerals to Support Activity
• 1. RDA recommendations sufficient
• 2. supplements do not improve performance
• 3. Vitamin E
• a. Exercise produces oxidation reactions
  leading to free radicals
• b. Vitamin E is an antioxidant

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Vitamins and Minerals to Support Activity (cont)

• 4. Iron
• a. Potential losses in sweat
• b. Increase in mitochondria requires more iron
• c. Increased destruction of red blood cells
  with exercise
• d. iron-deficiency
• 1. young women especially
• 2. could possibly impair performance
• 5. Sports anemia
• a. Initial loss of red blood cells
• b. Increase in blood volume

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Nutrients to Support Activity

• F. Fluids and Electrolytes
• 1. Fluids loss via sweat
• a. Each liter of sweat dissipates 600 kcal
  which equals about a 10oC increase in
  body temperature
• 2. Hyperthermia
• a. Elevated body temperature
• 1. Body cant control heat (hot, humid)
• 2. Could lead to heat stroke

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Heat stroke (cont)

• b. Symptoms of heat stroke
• 1. Headache
• 2. Nausea
• 3. dizziness, clumsiness
• 4. Stumbling
• 5. excessive or insufficient sweating
• 6. mental confusion

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Heat stroke (cont)

• c. Prevention of heat stroke
• 1. Fluids before, during after exercise
• a. 2 cups of water pre-event
• b. 1 cup every 15 minutes
• c. 2 cups after activity
• 2. Light clothing
• a. promote sweat evaporation

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Heat stroke (cont)

• 3. Sports drinks
• a. more concentrated than water
• b. Provide
• 1. Fluid
• 2. Glucose
• 3. sodium and other electrolytes
• 4. good taste
• 5. psychological edge

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Fluid Intake During Exercise
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III. Highlight Supplements and Ergogenic Aids

• A. Nutritional supplements
• 1. protein powders
• a. not needed
• b. burdens the kidney
• c. extra used as energy or stored as fat
• 2. amino acid supplements
• 3. vitamin and mineral supplements

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Supplements and Ergogenic Aids (cont)

• B. Soda Loading
• 1. minimal improvements
• 2. side effects
• C. Caffeine
• 1. research inconclusive
• 2. use in moderation
• 3. many side effects

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Supplements and Ergogenic Aids (cont)

• D. Anabolic Steroids
• 1. extensive use
• 2. established side effects
• 3. possible side effects
• E. Blood Doping