Chapter 10 Nutrients, Physical Activity, and the Body

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Chapter 10Nutrients, Physical Activity, and the
Bodys Responses

• Nutrition Concepts Controversies, 12e
  Sizer/Whitney

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Learning Objectives

• Discuss the short-term and long-term benefits of
  achieving cardiorespiratory fitness.
• Explain how the 2008 Physical Activity Guidelines
  for Americans can be incorporated into anyones
  lifestyle. Suggest simple ways to increase
  activity level throughout the day.

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Learning Objectives

• Explain why it is important for an athlete to
  maintain blood glucose levels before, during, and
  after vigorous exercise.
• Describe how an athletes body uses dietary
  protein during and after strenuous exercise.

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Learning Objectives

• Discuss some reasons why female endurance
  athletes may be vulnerable to iron deficiency.
• Evaluate whether conjugated linoleic acid (CLA)
  and other ergogenic aids are useful for obtaining
  an ideal body composition for sports.

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Introduction

• Physical activity and nutrition
• Needs
• Energy-yielding nutrients
• Vitamins and minerals
• Results
• Regulation of energy-yielding nutrients
• Body composition
• Daily calorie allowance

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Fitness

• Depends on physical activity or exercise
• Movement, muscle contraction, energy
  expenditure
• Benefits
• Chronic disease
• Longevity
• Disease resistance
• Numerous other benefits

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Physical Activity Guidelines

• 2008 Physical Activity Guidelines for Americans
• Aerobic physical activity resistance training
• Moderate vs. vigorous intensity
• Health-care provider advise
• Accumulated weekly totals
• Weight maintenance
• Sport performance

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Physical Activity Guidelines for Americans
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Intensity of Physical Activity
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American College of Sport Medicines Guidelines
for Physical Fitness
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The Essentials of Fitness

• Components of fitness
• Adaptations
• Athletes
• Muscle power
• Agility
• Reaction times
• Fatigue

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How Do Muscles Gain in Size and Strength?

• Activity choices
• Overload
• Balance of activity and rest
• Work different muscle groups
• Muscles need rest
• Replenish and adapt
• Specific training
• Hormones and muscle growth

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What Are the Benefits of Resistance Training?

• Progressive weight training
• Prevent and manage chronic disease
• Muscle strength size, power, or endurance
• Resistance and repetitions
• Appearance
• Mobility and bone loss
• Slows loss of physical mobility
• Maximize and maintain bone mass

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How Does Cardiorespiratory Training Benefit the
Heart?

• Enhances capacity
• Heart, lungs, and blood
• Enhances efficiency
• Delivery of oxygen
• VO2 max
• Removal of wastes
• Blood lipid profile
• Heart disease risk

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How Does Cardiorespiratory Training Benefit the
Heart?

• Effective training activities
• Elevate heart rate
• Sustained for longer than 20 minutes
• Use most of the large-muscle groups
• Pulse check

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The Active Bodys Use of Fuels

• Fuels
• Mixtures
• Vary
• Excess postexercise oxygen consumption (EPOC)
• High intensity activities
• Cardiac output
• Fuel usage

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Delivery of Oxygen by the Heart and Lungs to the
Muscles
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Glucose Use and Storage

• Muscle glucose
• Retains glycogen for own use
• Liver glucose
• Glycogen and endurance
• High-carbohydrate diets

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The Effect of Diet on Physical Endurance
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Activity Intensity, Glucose Use, and Glycogen
Stores

• Energy stored as glycogen
• Anaerobic use of glucose
• Quick energy
• Muscle glycogen reserves
• Aerobic use of glucose
• Energy from glucose and fatty acids
• Lactate
• Anaerobic activity
• Muscle size and strength

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Glucose and Fatty Acids in Their Energy-Releasing
Pathways in Muscle Cells
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Activity Duration, Glucose Use, and Glycogen
Stores

• Glucose use
• Duration of activity
• Intensity of activity
• Blood glucose and activity
• Dietary strategies
• High carbohydrate diet daily
• Consume glucose during activity
• Consume carbohydrate shortly after exercise

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Carbohydrate Needs of Athletes
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Degree of Training Affects Glycogen Use

• Muscles adapt to store more glycogen
• Trained muscles burn more fat

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Fat and Physical Activity

• Body fat as fuel for activity
• Sources of fat
• Importance of strength training
• Fat in the athletes diet
• Performance
• Omega-3 fatty acids
• Intensity and duration
• Degree of training

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Protein for Building Muscles and for Fuel

• Muscle protein synthesis
• Up to two days after activity
• Intensity and pattern of muscle contraction
• Muscle cells only build proteins as needed
• Dietary protein
• Supplements
• High-quality proteins
• Fuel for physical activity
• Factors that regulate protein use

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How Much Protein Should An Athlete Consume?

• DRI vs. other authorities
• Nature of chosen activity

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Do Nutrient Supplements Benefit Athletic
Performance?

• Well-nourished athletes
• More food means more nutrients
• Supplement timing
• Body use takes hours or days
• Preventing deficiencies
• Impede performance

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Nutrients of Concern

• Vitamin E
• Physical activity creates more free radicals
• Benefits of vitamin E supplements
• Studies are conflicting
• Interference with absorption
• Iron
• Deficiency impairs performance
• Groups at risk for deficiency
• Sports anemia

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Water Losses During Physical Activity

• Water losses
• Breathing and sweating
• Dehydration
• Sweat and temperature regulation
• Heat stroke
• Potentially fatal
• Reduce risk
• Hypothermia
• Symptoms

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Fluid and Electrolyte Needs During Physical
Activity

• Hydrate and rehydrate
• Thirst signal
• Hourly sweat rate
• Water
• Endurance athletes
• Electrolyte losses and replacement
• Minerals
• Sports drinks vs. regular diet

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Sodium Depletion and Water Intoxication

• Replenishing electrolytes
• Crucial time
• Hyponatremia
• Differs from dehydration
• Heat cramps
• Sodium

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Other Beverages

• Caffeine
• Moderate doses
• Iced tea
• Energy drinks
• Carbonated beverages
• Alcoholic beverages
• Diuretic

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What Do Sports Drinks Have to Offer?

• Fluid
• Glucose
• Sodium and other electrolytes
• Psychological edge

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Choosing a Performance Diet

• Nutrient density
• Balance
• Carbohydrate intake
• Liquid carbohydrate supplements
• Protein
• Milk and meat products

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Nutritious High-Carbohydrate Meals for Athletes
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Choosing a Performance Diet

• Planning an athletes meals
• Fruit and vegetable intake
• Pregame meals
• Easily digested
• Contain fluids
• Finish eating 3 to 4 hours before competition
• Complete bars and drinks

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Eating Patterns for Athletes
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Examples of High-Carbohydrate Pregame Meals
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Ergogenic Aids Breakthroughs, Gimmicks, or
Dangers?

• Controversy 10

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Ergogenic Aids

• Advertorials
• Dietary supplements
• Escape regulation
• Legitimate research
• Large majority of ergogenic aid claims are not
  supported

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Ergogenic Aids

• Caffeine
• Endurance vs. high-intensity activities
• Adverse effects
• Diuretic
• Carnitine
• Nonessential nutrient
• Chromium picolinate
• Carbohydrate and lipid metabolism
• Safety concerns

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Ergogenic Aids

• Creatine
• Hypothesized benefits
• Confirmed effect
• Weight gain
• Conjugated linoleic acid (CLA)
• Not worth their price
• Sodium bicarbonate
• Unpleasant side effects

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Ergogenic Aids

• Amino acid supplements
• Maximum gains
• Essential amino acids in system prior to physical
  work
• Best source
• Food
• Reasons against supplements

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Ergogenic Aids

• Whey protein and other protein supplements
• By product of cheese making
• Timing of protein intake
• Complete meal replacers
• Fall short of complete nutrition
• Risk of dental caries
• Nutritional uses
• Pregame meal
• Between-meal snack

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Hormone Preparations

• Anabolic steroid hormones
• Illegal and dangerous
• Steroid alternative supplements
• Herbal or insect sterols
• Prohormones
• Androstenedione
• DHEA
• Drugs posing as supplements

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Physical Risks of Taking Steroid Hormone Drugs