Chapter 10Chapter 10

Nutrients, Physical Activity, Nutrients, Physical Activity, and the Body’s Responsesand the Body’s Responses

Nutrition: Concepts & Controversies, 12e Nutrition: Concepts & Controversies, 12e Sizer/WhitneySizer/Whitney

Learning ObjectivesLearning 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 ObjectivesLearning 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 ObjectivesLearning 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.

IntroductionIntroduction

Physical activity and nutrition Needs

Energy-yielding nutrientsVitamins and minerals

ResultsRegulation of energy-yielding nutrientsBody compositionDaily calorie allowance

FitnessFitness

Depends on physical activity or exercise Movement, muscle contraction, & energy

expenditure Benefits

Chronic disease Longevity Disease resistance Numerous other benefits

Physical Activity GuidelinesPhysical 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 Physical Activity Guidelines for AmericansAmericans

Intensity of Physical ActivityIntensity of Physical Activity

American College of Sport Medicine’s American College of Sport Medicine’s Guidelines for Physical FitnessGuidelines for Physical Fitness

The Essentials of FitnessThe Essentials of Fitness

Components of fitness Adaptations

Athletes Muscle power Agility Reaction times Fatigue

How Do Muscles Gain in Size and How Do Muscles Gain in Size and Strength?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 What Are the Benefits of Resistance Training?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 How Does Cardiorespiratory Training Benefit the Heart?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 How Does Cardiorespiratory Training Benefit the Heart?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 FuelsThe 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 Delivery of Oxygen by the Heart and Lungs to the Musclesand Lungs to the Muscles

Glucose Use and StorageGlucose Use and Storage

Muscle glucose Retains glycogen for own use

Liver glucose Glycogen and endurance

High-carbohydrate diets

The Effect of Diet on Physical The Effect of Diet on Physical EnduranceEndurance

Activity Intensity, Glucose Use, Activity Intensity, Glucose Use, and Glycogen Storesand 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 Glucose and Fatty Acids in Their Energy-Releasing Pathways in Muscle Energy-Releasing Pathways in Muscle

CellsCells

Activity Duration, Glucose Use, Activity Duration, Glucose Use, and Glycogen Storesand Glycogen Stores

Glucose use Duration of activity Intensity of activity

Blood glucose and activity Dietary strategies

High carbohydrate diet dailyConsume glucose during activityConsume carbohydrate shortly after

exercise

Carbohydrate Needs of AthletesCarbohydrate Needs of Athletes

Degree of Training Affects Degree of Training Affects Glycogen UseGlycogen Use

Muscles adapt to store more glycogen

Trained muscles burn more fat

Fat and Physical ActivityFat 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 Protein for Building Muscles and for Fuelfor 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 How Much Protein Should An Athlete Consume?Athlete Consume?

DRI vs. other authorities Nature of

chosen activity

Do Nutrient Supplements Benefit Do Nutrient Supplements Benefit Athletic Performance?Athletic Performance?

Well-nourished athletes More food means more nutrients

Supplement timing Body use takes hours or days

Preventing deficiencies Impede performance

Nutrients of ConcernNutrients 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 Water Losses During Physical ActivityActivity

Water losses Breathing and sweating

Dehydration Sweat and temperature regulation Heat stroke

Potentially fatal Reduce risk

Hypothermia Symptoms

Fluid and Electrolyte Needs Fluid and Electrolyte Needs During Physical Activity 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 Sodium Depletion and Water Intoxication Intoxication

Replenishing electrolytes Crucial time Hyponatremia

Differs from dehydration Heat cramps

Sodium

Other BeveragesOther Beverages

Caffeine Moderate doses

Iced teaEnergy drinks

Carbonated beverages Alcoholic beverages

Diuretic

What Do Sports Drinks Have to What Do Sports Drinks Have to Offer?Offer?

Fluid Glucose Sodium and other electrolytes Psychological edge

Choosing a Performance DietChoosing a Performance Diet

Nutrient density Balance

Carbohydrate intakeLiquid carbohydrate supplements

Protein Milk and meat products

Nutritious High-Carbohydrate Nutritious High-Carbohydrate Meals for AthletesMeals for Athletes

Choosing a Performance DietChoosing a Performance Diet

Planning an athlete’s meals Fruit and vegetable intake Pregame meals

Easily digestedContain fluidsFinish eating 3 to 4 hours before

competition “Complete” bars and drinks

Eating Patterns for AthletesEating Patterns for Athletes

Examples of High-Carbohydrate Examples of High-Carbohydrate Pregame MealsPregame Meals

Ergogenic Aids: Breakthroughs, Ergogenic Aids: Breakthroughs, Gimmicks, or Dangers?Gimmicks, or Dangers?

Controversy 10

Ergogenic AidsErgogenic Aids

Advertorials Dietary supplements

Escape regulation Legitimate research

Large majority of ergogenic aid claims are not supported

Ergogenic AidsErgogenic Aids

Caffeine Endurance vs. high-intensity activities Adverse effects Diuretic

Carnitine Nonessential nutrient

Chromium picolinate Carbohydrate and lipid metabolism Safety concerns

Ergogenic AidsErgogenic Aids

Creatine Hypothesized benefits Confirmed effect

Weight gain

Conjugated linoleic acid (CLA) Not worth their price

Sodium bicarbonate Unpleasant side effects

Ergogenic AidsErgogenic Aids

Amino acid supplements Maximum gains

Essential amino acids in system prior to physical work

Best sourceFoodReasons against supplements

Ergogenic AidsErgogenic 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 mealBetween-meal snack

Hormone PreparationsHormone 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 Physical Risks of Taking Steroid Hormone DrugsHormone Drugs