Lecture Outline Chapter 11 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

LectureLectureOutlineOutline

Chapter 11Chapter 11

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Nutrition for Physically- Nutrition for Physically- Active LifestylesActive Lifestyles

Chapter 11Chapter 11 Insert chapter opener photo

Chapter Learning OutcomesChapter Learning Outcomes

1.1. List five health benefits of a physically-active List five health benefits of a physically-active lifestyle.lifestyle.

2.2. Differentiate between anaerobic and aerobic Differentiate between anaerobic and aerobic use of energy, and identify advantages and use of energy, and identify advantages and disadvantages of each.disadvantages of each.

3.3. Plan nutritionally adequate, high-carbohydrate Plan nutritionally adequate, high-carbohydrate menus.menus.

4.4. Estimate an athlete’s energy and protein needs.Estimate an athlete’s energy and protein needs.5.5. List at least five ergogenic aids that athletes List at least five ergogenic aids that athletes

often use, and describe their effects on health often use, and describe their effects on health and physical performance.and physical performance.

6.6. Design a personal fitness regimen that suits Design a personal fitness regimen that suits your interests and lifestyle.your interests and lifestyle.

Quiz YourselfQuiz Yourself True or FalseTrue or False

1.1. People who exercise regularly can reduce their People who exercise regularly can reduce their risk of type 2 diabetes. risk of type 2 diabetes. T FT F

2.2. Sports drinks are not useful for fluid Sports drinks are not useful for fluid replacement. replacement. T FT F

3.3. Protein is the body’s preferred fuel for muscular Protein is the body’s preferred fuel for muscular activity. activity. T FT F

4.4. Heatstroke is a serious illness that requires Heatstroke is a serious illness that requires immediate professional medical treatment. immediate professional medical treatment. T FT F

5.5. While at rest, skeletal muscles metabolize more While at rest, skeletal muscles metabolize more glucose than fat for energy. glucose than fat for energy. T FT F

Quiz YourselfQuiz Yourself True or FalseTrue or False

1.1. TrueTrue Engaging in exercise regularly Engaging in exercise regularly cancan reduce reduce the risk of type 2 diabetes.the risk of type 2 diabetes.

2.2. FalseFalse Sports drinks Sports drinks can becan be useful for fluid useful for fluid replacement.replacement.

3.3. FalseFalse Protein is Protein is notnot the body’s preferred fuel for the body’s preferred fuel for muscular activity.muscular activity.

4.4. True True Heatstroke is a serious illness that Heatstroke is a serious illness that requires immediate professional medical requires immediate professional medical treatment.treatment.

5.5. FalseFalse While at rest, skeletal muscles While at rest, skeletal muscles metabolize more metabolize more fatfat for energy. for energy.

Key Terms

• Physical ActivityPhysical Activity– Movement resulting from skeletal muscle

contraction

• ExerciseExercise– Physical activities that are usually planned

and structured for a purpose

• Physical FitnessPhysical Fitness– Ability to perform moderate- to vigorous-

intensity activities without becoming excessively fatigued

Benefits of Regular Exercise

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Determining the Intensity of Physical Activity

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Determining the Intensity of Physical Activity

• IntensityIntensity– Level of exertion used to perform an activity

• Factors that influence intensityFactors that influence intensity:– DurationDuration– Type of activityType of activity– Body weightBody weight

• MethodsMethods of determining intensityof determining intensity:– Assess breathing ratebreathing rate – Assess heart rateheart rate

Calculating Age-Related Maximum Heart Rate

To calculate your age-related maximum heart rate, subtract your age from 220– Target heart rate zone:Target heart rate zone: range of heart rate that

reflects the intensity of exertion during physical activity

Moderate intensity Moderate intensity — target zone is 50 to 70%50 to 70% of age-related maximum

Vigorous intensity Vigorous intensity — target zone is 70 to 85%70 to 85% of age-related maximum

Physical Activity Pyramid

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Aerobic and Resistance Exercises

• Aerobic exercise– Sustained, rhythmic

contractions of large muscle groups

– Raises heart rate giving the heart an effective workout

• Resistance exercise– Activities that increase

muscle mass and strength

– Resistance exercises also increase bone mass.

Energy for Muscular Work

Cells obtain energy through a series of chemical reactions – CatabolismCatabolism of glucose, fatty acids, amino

acids, or alcohol

• Energy stored in carbon-hydrogen bonds is captured in the high energy compound ATPATP

• ATPATP forms when an inorganic phosphate group (Pi ) bonds with ADP.

ATPATP

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Energy from Glucose

Glucose can be catabolizd anaerobically anaerobically oror aerobicallyaerobically

– Catabolism involves oxidation,oxidation, removal of electrons from one compound to create another.

• The first stage of glucose oxidationglucose oxidation is glycolysisglycolysis — splitting of a glucose molecule to form

two pyruvatepyruvate molecules.– Occurs under anaerobicanaerobic conditions– A small amount of ATP is formed by glycolysis.

Glycolysis

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Further Oxidation of Glucose

If oxygen is available, pyruvatepyruvate can enter aerobic respiration pathways.

– Pyruvate moves from cytoplasm into mitochondria mitochondria — “powerhouses” of cells.

– In mitochondria, pyruvate is completely oxidized, forming ATPATP, COCO22, and HH22O.O.

Aerobic Respiration

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Summary of ATP Formation

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How Do Cells Use ATP?

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Energy Systems for Exercising Muscles

Why is glucose best biological fuel for intense, brief exercise?

– Fatty acids have fewer oxygen atoms in relation to carbons.• Thus, cells require more oxygen to

metabolize fat.• During brief bouts of intense exercise,

lungs and heart cannot deliver enough oxygen to muscles for fatty acid oxidation.

Three Major Energy Systems

• PhosphocreatinePhosphocreatine (PCrPCr)– anaerobic

• Lactic acidLactic acid– anaerobic

• OxygenOxygen – aerobic

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PCr-ATP Energy System

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Muscles contain enough ATP to last about 1 second.

PCrPCr provides the energy by providing Pi to ADPforming ATP .

PCrPCr supplies muscles with ~ 6 seconds of energy.

Lactic Acid Energy System• In anaerobic conditions, glucose is converted to

pyruvatepyruvate and then lactic acid.lactic acid. – Enough ATP is formed to last 3030 to 4040 sec.

• Lactic acidLactic acid releases hydrogen ions, hydrogen ions, and becomes lactate.lactate.– Certain muscles can use some lactateCertain muscles can use some lactate for energy.– Most lactatelactate enters the bloodstream.

• Liver removes lactate and converts it to glucose.

Lactic Acid

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Oxygen Energy System

• During low- to moderate-intensity exercise (aerobicaerobic conditions), muscle cells can completely metabolize glucose.

Produces ~18 times18 times more ATP than during anaerobic conditions

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Fat or Carbohydrate for Fueling Exercise?

IntensityIntensity of activity influences type of fuel use

–Fat predominates when at rest and during low- to moderate-intensity activities

–Carbohydrate is main fuel for high-intensity activities

–Protein contributes a small amount of energy, with slightly more during endurance exercise

General Dietary Advice for Athletes

Factors that influence athletic performance:• Genetic endowment• Physical training• Diet

– Many athletes and coaches believe sports nutrition misinformation often in advertisements, magazines articles, and the Internet.

– Sports nutritionSports nutrition:: applying nutrition principles and research findings to improving athletic performance

Energy for Athletic Performance

Most athletes need at least 3000 kcal/day.– Males generally need 50 kcal/kg/day.– Females generally need 45-50 kcal/kg/day.

Methods to determine adequate caloric intake:– Keep a food log– Monitor body weight

Fat should supply 20 to 35% of energy.

Focusing on Carbohydrate Intake

• Athletes should consume >60% of kcal from carbohydrates.

Do the math to determine % kcal from carbohydrates:

A person consumes 3000 kcal/day:– Step 1 Determine 60% of 3000 kcal:

• 60% = 0.60

• 0.60 x 3000 = 1800 kcal– Step 2 Determine grams of carbohydrate in 1800 kcal by

dividing kcal by 4. (Note: 1 g of “carbs” supplies 4 kcal)• 1800 kcal 4 kcal/g = 450 g

Carbohydrate Intake

• To maintain adequate glycogen stores, athletes need 6 to 10 g of carbohdrate/kg body weight

To determine carbohydrate intake range: Example: A person weighs 145145 lbs.

– Step 1. Convert lbs to kg by dividing weight by 2.2• 145 2.2 = 66 kg

– Step 2. To determine the range of carbohydrate intake, multiply body wt in kg by 6 and then by 10

• For 6 g/kg 6 g x 66 kg = 396 g of “carbs”• For 10 g/kg 10g x 66 kg = 660 g of “carbs”

Pre-Event Meal

RecommendationsRecommendations: – About 2 to 4 hrs before event, eat a low-fat meal.

• Provides ~ 100 g of carbohydrate

• Total meal should supply ~ 500 to 600 kcal

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Energy and Macronutrient

Content of Selected

Foods

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What Is Carbohydrate Loading?

CHO loading: manipulating physical activity and dietary patterns, a few days before an event

Goal is to increase muscle glycogen stores

• Typical technique: 7 days before event– Day 1 - Train intensely– Days 2 to 4 - Gradually taper off training with

moderate carbohydrate (~ 300 g) intake – Days 5 to 7 - Exercise lightly and rest on the last day

with high carbohydrate (400 to 700 g) intake

• The diet and training manipulation greatly increase glycogen stores.

Consuming Carbohydrate During and After Events

During • Vigorous exercise >60

minutes depletes glycogen stores: – Athletes “hit the wallhit the wall”

• RecommendationRecommendation: Consume 30 to 60 g carbohydrates/hr.

• Food sourcesFood sources: Sports drinks, sports gels, or other sources of carbohydrate

After• Trained athletes can

replenish most of their glycogen stores in a few days.

• RecommendationRecommendation: 8 to 10 g carbohydrate/kg body wt/day

• To replenish glycogen To replenish glycogen quickly after intense quickly after intense exerciseexercise: sports drinks, sugar-sweetened soft drinks, fruit, or fruit juices

Raising the Bar?

What about energy bars, gels and drinksWhat about energy bars, gels and drinks??• Energy barsEnergy bars are made from soy or milk

proteins fortified with vitamins, minerals, and fiber.

• No scientific evidence for benefits to performance• Regular granola bars are cheaper source of

nutrients and fiber.

• Energy drinksEnergy drinks typically contain sugars and caffeine.

• Some contain ginseng ginseng – may enhance effects of caffeine

What About Proteins?

For many athletes, protein intakes are higher than recommendations.

• Protein recommendationsProtein recommendations for athletes:• EnduranceEndurance: 1.2 to 1.4 g/kg of body

weight/day• ResistanceResistance: 1.6 to 1.7 g/kg of body

weight/day

Popular Energy Bars and Gels

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Focusing on Fluids

Adequate Intake for Total Adequate Intake for Total WaterWater: – 11 cups for young women– 15.5 cups for young men

Water needsWater needs vary, depending on:– Sport– Fitness level– Environmental conditions

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Heat-Related Illnesses

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Replenishing Fluids

To reduce risk of heat-related illness:heat-related illness: AvoidAvoid exercising in extremely hot, humid

weather and replace lost fluids.

To estimate fluid needs, weigh yourself prior to exercising and again after.

• If difference is >2>2%, fluid replacement is needed.

• General recommendationGeneral recommendation: Drink 20 to 24 oz of fluids for each 1 pound of body weight lost during exercise.

Do I Need a Sports Drink?

Sports drinks provide benefits over plain water• Carbohydrate

– Sports drinks provide desirable carbohydrate content (6%)

– Soft drinks and juices provide >10% carbohydrate

• Sodium and electrolytes– Enhance water and carbohydrate absorption

and stimulate thirst• Sports drinks generally recommended when

event lasts longer than 30 minutes

Antioxidant Vitamins

Free radical formation increases during aerobic exercise.– Oxidative stress may contribute to muscle

fatigue and damage.• Intense exercise may stimulate the body’s natural

antioxidant defense system .– Taking antioxidant supplements may block this

process.• Therefore, taking antioxidant supplements is not

recommended.

Iron

Iron is needed to produce red blood cells, transport oxygen, and obtain energy.– Athletes at risk for iron deficiency include:

• Females• Distance runners• Vegetarians (especially vegans)

• Sports anemia — temporary condition resulting from an increase in plasmaplasma (liquid portion of blood)– May be difficult to distinguish between sports

anemia and true anemia

Calcium

• Vegans and people who restrict intake of milk and milk products are at risk for calcium deficiency.– Weak bones or osteoporosis may result.

• Female athletes who have irregular or no menstrual cycles may be deficient in estrogen. – Weight bearing exercise increases bone

density, but estrogen is needed to maintain healthy bones.

Ergogenic Aids

What are What are ergogenic aidsergogenic aids??– Foods, devices, dietary supplements, or drugs used Foods, devices, dietary supplements, or drugs used

to improve physical performanceto improve physical performance– Are they effective?Are they effective?

• Little reliable scientific evidence supports effectiveness of most dietary supplements.

• Sufficient water and electrolytes, carbohydrates, and a balanced and varied diet are the most important ergogenic aids.

Evaluation of Some Ergogenic Aids

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Caffeine

Caffeine -- most widely used ergogenic aidergogenic aid– How caffeine affects athletic performance:

• BenefitsBenefits– Raises blood fatty acid levels– Enhances contraction of skeletal and heart muscles – Increases mental alertness

• Adverse effectsAdverse effects– Shakiness – Rapid heart beat– Sleep disturbances– Diarrhea and frequent urination

Caffeine Content of Selected Beverages

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Chapter 11 Highlight: Developing a Personal Physical Fitness Plan

• Most healthy people can gradually increase Most healthy people can gradually increase physical activity levels.physical activity levels.

• Older adults or those with any chronic health Older adults or those with any chronic health condition should consult a physician before condition should consult a physician before starting a physical fitness program.starting a physical fitness program.

Stages of Fitness Plan

• Initiation—first 3to 6 weeks—first 3to 6 weeks– Incorporate short periods of activity to total 30 Incorporate short periods of activity to total 30

minutes on most days. minutes on most days. (For example, gardening or taking (For example, gardening or taking the stairs instead of elevators)the stairs instead of elevators)

• Improvement—the next 5 to 6 monthsImprovement—the next 5 to 6 months– Increase intensity and duration of exercises.Increase intensity and duration of exercises.– Exercise near the lower end of target heart rate zone.Exercise near the lower end of target heart rate zone.

• Maintenance—at 5 to 6 monthsMaintenance—at 5 to 6 months– Fitness goals are reachedFitness goals are reached– Continue present programContinue present program

Components of a Workout Regimen

• Warm-upWarm-up• Aerobic workoutAerobic workout

– TypeType– DurationDuration– FrequencyFrequency– IntensityIntensity– ProgressionProgression

• Cool downCool down

Types of Training

• What about strength (resistance) training?What about strength (resistance) training?– Include strength training 2 to 3 days per weekInclude strength training 2 to 3 days per week– May use weight, machines or elastic exercise cordsMay use weight, machines or elastic exercise cords

• Mixing it upMixing it up– Include several types of physical activity each week.Include several types of physical activity each week.– Having an exercise partner provides motivation and Having an exercise partner provides motivation and

encouragement.encouragement.– Include variety, balance, and moderation in the Include variety, balance, and moderation in the

exercise routine.exercise routine.