Chapter 10 Nutrients, Physical Activity, and the Body’s Responses

1. Chapter 10Nutrients, Physical Activity, and the Body’s Responses Nutrition: Concepts & Controversies, 12e Sizer/Whitney

2. 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.

3. 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.

4. 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.

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

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

7. 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

8. Physical Activity Guidelines for Americans

9. Intensity of Physical Activity

10. American College of Sport Medicine’s Guidelines for Physical Fitness

11. The Essentials of Fitness • Components of fitness • Adaptations • Athletes • Muscle power • Agility • Reaction times • Fatigue

12. 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

13. 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

14. 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

15. 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

16. The Active Body’s Use of Fuels • Fuels • Mixtures • Vary • Excess postexercise oxygen consumption (EPOC) • High intensity activities • Cardiac output • Fuel usage

17. Delivery of Oxygen by the Heart and Lungs to the Muscles

18. Glucose Use and Storage • Muscle glucose • Retains glycogen for own use • Liver glucose • Glycogen and endurance • High-carbohydrate diets

19. The Effect of Diet on Physical Endurance

20. 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

21. Glucose and Fatty Acids in Their Energy-Releasing Pathways in Muscle Cells

22. 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

23. Carbohydrate Needs of Athletes

24. Degree of Training Affects Glycogen Use • Muscles adapt to store more glycogen • Trained muscles burn more fat

25. 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

26. 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

27. How Much Protein Should An Athlete Consume? • DRI vs. other authorities • Nature of chosen activity

28. 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

29. 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

30. Water Losses During Physical Activity • Water losses • Breathing and sweating • Dehydration • Sweat and temperature regulation • Heat stroke • Potentially fatal • Reduce risk • Hypothermia • Symptoms

31. 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

32. Sodium Depletion and Water Intoxication • Replenishing electrolytes • Crucial time • Hyponatremia • Differs from dehydration • Heat cramps • Sodium

33. Other Beverages • Caffeine • Moderate doses • Iced tea • Energy drinks • Carbonated beverages • Alcoholic beverages • Diuretic

34. What Do Sports Drinks Have to Offer? • Fluid • Glucose • Sodium and other electrolytes • Psychological edge

35. Choosing a Performance Diet • Nutrient density • Balance • Carbohydrate intake • Liquid carbohydrate supplements • Protein • Milk and meat products

36. Nutritious High-Carbohydrate Meals for Athletes

37. 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

38. Eating Patterns for Athletes

39. Examples of High-Carbohydrate Pregame Meals

40. Ergogenic Aids: Breakthroughs, Gimmicks, or Dangers? Controversy 10

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

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

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

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

45. 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

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

47. Physical Risks of Taking Steroid Hormone Drugs