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Lecture Outline Chapter 11 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Nutrition for Physically- Active Lifestyles Chapter 11 Insert chapter opener photo
Chapter Learning Outcomes 1.List five health benefits of a physically-active lifestyle. 2.Differentiate between anaerobic and aerobic use of energy, and identify advantages and disadvantages of each. 3.Plan nutritionally adequate, high-carbohydrate menus. 4.Estimate an athletes energy and protein needs. 5.List at least five ergogenic aids that athletes often use, and describe their effects on health and physical performance. 6.Design a personal fitness regimen that suits your interests and lifestyle.
Quiz Yourself True or False Quiz Yourself True or False 1.People who exercise regularly can reduce their risk of type 2 diabetes. T F 2.Sports drinks are not useful for fluid replacement. T F 3.Protein is the bodys preferred fuel for muscular activity. T F 4.Heatstroke is a serious illness that requires immediate professional medical treatment. T F 5.While at rest, skeletal muscles metabolize more glucose than fat for energy. T F
Quiz Yourself True or False Quiz Yourself True or False 1.True Engaging in exercise regularly can reduce the risk of type 2 diabetes. 2.False Sports drinks can be useful for fluid replacement. 3.False Protein is not the bodys preferred fuel for muscular activity. 4.True Heatstroke is a serious illness that requires immediate professional medical treatment. 5.False While at rest, skeletal muscles metabolize more fat 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 Insert figure 11.1
Determining the Intensity of Physical Activity Insert figure 11.1
Determining the Intensity of Physical Activity IntensityIntensity –Level of exertion used to perform an activity Factors that influence intensityFactors that influence intensity: –Duration –Type of activity –Body weight Methodsof determining intensityMethods of determining intensity: breathing rate –Assess breathing rate heart rate –Assess heart 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 50 to 70% Moderate intensity target zone is 50 to 70% of age-related maximum Vigorous intensity 70 to 85% Vigorous intensity target zone is 70 to 85% of age-related maximum
Physical Activity Pyramid Insert figure 11.3
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 Catabolism – Catabolism of glucose, fatty acids, amino acids, or alcohol ATPEnergy stored in carbon-hydrogen bonds is captured in the high energy compound ATP ATPATP forms when an inorganic phosphate group (P i ) bonds with ADP.
ATP Insert figure 11.4
Energy from Glucose anaerobically or aerobically Glucose can be catabolizd anaerobically or aerobically oxidation, –Catabolism involves oxidation, removal of electrons from one compound to create another. glucose oxidationglycolysis pyruvateThe first stage of glucose oxidation is glycolysis splitting of a glucose molecule to form two pyruvate molecules. anaerobic –Occurs under anaerobic conditions –A small amount of ATP is formed by glycolysis.
Glycolysis Insert Figure 11.5
Further Oxidation of Glucose pyruvate If oxygen is available, pyruvate can enter aerobic respiration pathways. mitochondria –Pyruvate moves from cytoplasm into mitochondria powerhouses of cells. ATPCO 2 H 2 O. –In mitochondria, pyruvate is completely oxidized, forming ATP, CO 2, and H 2 O.
Aerobic Respiration Insert Figure 11.5
Summary of ATP Formation Insert figure 11.6
How Do Cells Use ATP? Insert figure 11.7
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 PhosphocreatinePCrPhosphocreatine (PCr) – anaerobic Lactic acidLactic acid – anaerobic OxygenOxygen – aerobic Insert photo of man from bottom of page 379
PCr-ATP Energy System Insert figure 11.8 Muscles contain enough ATP to last about 1 second. PCr PCr provides the energy by providing P i to ADP forming ATP. PCr PCr supplies muscles with ~ 6 seconds of energy.
Lactic Acid Energy System pyruvatelactic acid.In anaerobic conditions, glucose is converted to pyruvate and then lactic acid –Enough ATP is formed to last 30 to 40 sec. Lactic acidhydrogen ions, lactate.Lactic acid releases hydrogen ions, and becomes lactate. –Certain muscles can use some lactate –Certain muscles can use some lactate for energy. lactate –Most lactate enters the bloodstream. Liver removes lactate and converts it to glucose.
Lactic Acid Insert figure 11.9
Oxygen Energy System aerobicDuring low- to moderate- intensity exercise (aerobic conditions), muscle cells can completely metabolize glucose. 18 times Produces ~18 times more ATP than during anaerobic conditions Insert photo of runner from page 383
Fat or Carbohydrate for Fueling Exercise? Intensity Intensity 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 nutrition: –Sports 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 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% = 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: 145 Example: A person weighs 145 lbs. –Step 1. Convert lbs to kg by dividing weight by = 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 Recommendations Recommendations: –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 Insert Table 11.3
Energy and Macronutrient Content of Selected Foods Insert Table 11.4
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: hit the wall –Athletes hit 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 quickly after intense exerciseTo replenish glycogen quickly after intense exercise: sports drinks, sugar-sweetened soft drinks, fruit, or fruit juices
Raising the Bar? What 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. ginsengSome contain 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 Insert table 11.5
Focusing on Fluids Adequate Intake for Total Water Adequate Intake for Total Water: –11 cups for young women –15.5 cups for young men Water needs Water needs vary, depending on: –Sport –Fitness level –Environmental conditions Insert photo of man drinking water from page 390
Heat-Related Illnesses Insert table 11.6
Replenishing Fluids heat-related illness: To reduce risk of heat-related illness: Avoid Avoid exercising in extremely hot, humid weather and replace lost fluids. To estimate fluid needs, weigh yourself prior to exercising and again after. >2If difference is >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 bodys 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) plasmaSports anemia temporary condition resulting from an increase in plasma (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 ergogenic aids? –Foods, devices, dietary supplements, or drugs used to improve physical performance –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 Insert table 11.7
Caffeine ergogenic aid Caffeine --most widely used ergogenic 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 Insert Table 11.8
Chapter 11 Highlight: Developing a Personal Physical Fitness Plan Most healthy people can gradually increase physical activity levels.Most healthy people can gradually increase physical activity levels. Older adults or those with any chronic health condition should consult a physician before starting a physical fitness program.Older adults or those with any chronic health condition should consult a physician before starting a physical fitness program.
Stages of Fitness Plan first 3to 6 weeksInitiationfirst 3to 6 weeks –Incorporate short periods of activity to total 30 minutes on most days. (For example, gardening or taking the stairs instead of elevators) Improvementthe next 5 to 6 monthsImprovementthe next 5 to 6 months –Increase intensity and duration of exercises. –Exercise near the lower end of target heart rate zone. Maintenanceat 5 to 6 monthsMaintenanceat 5 to 6 months –Fitness goals are reached –Continue present program
Components of a Workout Regimen Warm-upWarm-up Aerobic workoutAerobic workout –Type –Duration –Frequency –Intensity –Progression Cool downCool down
Types of Training What about strength (resistance) training?What about strength (resistance) training? –Include strength training 2 to 3 days per week –May use weight, machines or elastic exercise cords Mixing it upMixing it up –Include several types of physical activity each week. –Having an exercise partner provides motivation and encouragement. –Include variety, balance, and moderation in the exercise routine.