Transcript 2008 Physical Activity Guidelines for Americans

Chapter 10
Nutrients, Physical Activity,
and the Body’s Responses
Nutrition: Concepts & Controversies, 12e
Sizer/Whitney
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 anyone’s lifestyle.
Suggest simple ways to increase activity
level throughout the day.
Learning Objectives
 Explain why it is important for an athlete to
maintain blood glucose levels before,
during, and after vigorous exercise.
 Describe how an athlete’s body uses
dietary protein during and after strenuous
exercise.
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.
Introduction
 Physical activity and nutrition
 Needs
 Energy-yielding nutrients
 Vitamins and minerals
 Results
 Regulation of energy-yielding nutrients
 Body composition
 Daily calorie allowance
Fitness
 Depends on physical activity or exercise
 Movement, muscle contraction, & energy
expenditure
 Benefits
 Chronic disease
 Longevity
 Disease resistance
 Numerous other benefits
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
Physical Activity Guidelines for
Americans
Intensity of Physical Activity
American College of Sport Medicine’s
Guidelines for Physical Fitness
The Essentials of Fitness
 Components of fitness
 Adaptations
 Athletes
 Muscle power
 Agility
 Reaction times
 Fatigue
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
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
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
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
The Active Body’s Use of Fuels
 Fuels
 Mixtures
 Vary
 Excess postexercise oxygen consumption
(EPOC)
 High intensity activities
 Cardiac output
 Fuel usage
Delivery of Oxygen by the Heart
and Lungs to the Muscles
Glucose Use and Storage
 Muscle glucose
 Retains glycogen for own use
 Liver glucose
 Glycogen and endurance
 High-carbohydrate diets
The Effect of Diet on Physical
Endurance
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
Glucose and Fatty Acids in Their
Energy-Releasing Pathways in Muscle
Cells
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
Carbohydrate Needs of Athletes
Degree of Training Affects
Glycogen Use
 Muscles adapt to
store more
glycogen
 Trained muscles
burn more fat
Fat and Physical Activity
 Body fat as fuel for activity
 Sources of fat
 Importance of strength training
 Fat in the athlete’s diet
 Performance
 Omega-3 fatty acids
 Intensity and duration
 Degree of training
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
How Much Protein Should An
Athlete Consume?
 DRI vs.
other
authorities
 Nature of
chosen
activity
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
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
Water Losses During Physical
Activity
 Water losses
 Breathing and sweating
 Dehydration
 Sweat and temperature regulation
 Heat stroke
 Potentially fatal
 Reduce risk
 Hypothermia
 Symptoms
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
Sodium Depletion and Water
Intoxication
 Replenishing electrolytes
 Crucial time
 Hyponatremia
 Differs from dehydration
 Heat cramps
 Sodium
Other Beverages
 Caffeine
 Moderate doses
 Iced tea
 Energy drinks
 Carbonated beverages
 Alcoholic beverages
 Diuretic
What Do Sports Drinks Have to
Offer?




Fluid
Glucose
Sodium and other electrolytes
Psychological edge
Choosing a Performance Diet
 Nutrient density
 Balance
 Carbohydrate intake
 Liquid carbohydrate supplements
 Protein
 Milk and meat products
Nutritious High-Carbohydrate
Meals for Athletes
Choosing a Performance Diet
 Planning an athlete’s meals
 Fruit and vegetable intake
 Pregame meals
 Easily digested
 Contain fluids
 Finish eating 3 to 4 hours before
competition
 “Complete” bars and drinks
Eating Patterns for Athletes
Examples of High-Carbohydrate
Pregame Meals
Ergogenic Aids: Breakthroughs,
Gimmicks, or Dangers?
Controversy 10
Ergogenic Aids
 Advertorials
 Dietary supplements
 Escape regulation
 Legitimate research
 Large majority of ergogenic aid claims are
not supported
Ergogenic Aids
 Caffeine
 Endurance vs. high-intensity activities
 Adverse effects
 Diuretic
 Carnitine
 Nonessential nutrient
 Chromium picolinate
 Carbohydrate and lipid metabolism
 Safety concerns
Ergogenic Aids
 Creatine
 Hypothesized benefits
 Confirmed effect
 Weight gain
 Conjugated linoleic acid (CLA)
 Not worth their price
 Sodium bicarbonate
 Unpleasant side effects
Ergogenic Aids
 Amino acid supplements
 Maximum gains
 Essential amino acids in system prior to
physical work
 Best source
 Food
 Reasons against supplements
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
Hormone Preparations
 Anabolic steroid hormones
 Illegal and dangerous
 Steroid alternative supplements
 Herbal or insect sterols
 Prohormones
 Androstenedione
 DHEA
 Drugs posing as supplements
Physical Risks of Taking Steroid
Hormone Drugs