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11. Nutrition, Physical Activity , and Fitness. Chapter Objectives. 11.1 Describe the health benefits of living a physically active lifestyle. 11.2 Identify the four components of fitness and strategies to achieve overall fitness.
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11 Nutrition, Physical Activity, and Fitness
Chapter Objectives 11.1 Describe the health benefits of living a physically active lifestyle. 11.2 Identify the four components of fitness and strategies to achieve overall fitness. 11.3 Identify the factors that influence fuel use during physical activity. 11.4 Describe the use of glycogen and body fat during physical activity.
Chapter Objectives 11.5 Determine the protein needs of an athlete. 11.6 Identify the factors that influence an athlete’s fluid needs and describe the recommended schedule of hydration before, during, and after exercise.
Chapter Objectives 11.7 Describe how vitamins and minerals are used during physical activity 11.8 Discuss the safety and efficacy of popular ergogenic aids used by athletes.
Introduction • There is a two-way relationship between nutrition and fitness • Both are essential components of good health • Recent health initiatives • Let’s Move! Initiative: focuses on child obesity • President’s Council on Fitness, Sports, and Nutrition • 33 percent of adults exercise regularly • 38 percent report no physical activity
11.1 Getting Started on Lifetime Fitness • The Physical Activity Guidelines for Americans • Moderate-intensity physical activity for 2-1/2 hours each week –OR– • Vigorous-intensity aerobic physical activity for 1 hour and 15 minutes each week • Note: greater benefits occur with more physical activity
11.1 Getting Started on Lifetime Fitness • Physical activity program for total fitness includes • Aerobic activity • Strength training • Stretching • Physical activity time is a lifelong commitment
11.1 Getting Started on Lifetime Fitness • Seek medical advice if your profile includes risk factors for heart disease • Sedentary lifestyle • Family history of heart disease • Cigarette smoking • High blood pressure • High blood cholesterol (> 200 mg/dL) • Obesity (BMI ≥ 30) • Diabetes
11.2 The Components of Fitness • Physical conditioning: a planned program of physical activity • Directed toward improving the function of a particular body system • Employs overload principal: causes the body to adapt and function more efficiently • Ways to apply overload • Increase frequency • Increase intensity • Increase duration
11.2 The Components of Fitness • Strength: ability of the muscles to work against resistance • Resistance training has many benefits • Build well-toned muscles needed for daily activities at work and during recreation • Strong muscles, tendons, and ligaments are less prone to injury • Helps with weigh loss: increases BMR
11.2 The Components of Fitness • Flexibility: range of motion • Depends on the elasticity of the muscles, tendons, and ligaments and on the condition of the joints • Tends to decrease with age • Improves in response to stretching and can be maintained by frequent stretching exercises
11.2 The Components of Fitness • Muscle endurance • Ability of a muscle to contract repeatedly within a given time without becoming exhausted • Impacts performance as an activity continues • 18th hole of a golf game • Pedaling the last 10 miles of a 100-mile bike tour • Tests for specific muscles • Number of sit-ups or push-ups in a specified time period
11.2 The Components of Fitness • Cardiovascular endurance • The heart is a muscle: responds to repeated demands by becoming larger and stronger • Best types of activities to improve cardiovascular endurance use large muscle groups, i.e., arms and legs • American College of Sports Medicine recommends cardiovascular conditioning • At least five times a week • Continuous 30 to 60 minutes each session
Nutrition Action: Nutrition and Fitness—Forever Young • Physical inactivity in sedentary societies • Directly contributes to multiple chronic health disorders • Humans are genetically “programmed” to expect physical activity • Our bodies’ biochemistry and physiology was fine-tuned by and for conditions of life that existed more than 10,000 years ago • Physical activity is a choice in fighting against life-threatening diseases
11.3 Energy for Physical Activity • Metabolism: chemical process • Converts water, oxygen, and food to energy • Aerobic metabolism depends on oxygen • Anaerobic metabolism is performed without oxygen
11.3 Energy for Physical Activity • Aerobic and anaerobic metabolism • Moderate activity level allows the heart and lungs to supply the oxygen needed to perform aerobic metabolism • Muscle exertion with energy demand that outstrips the oxygen supply must also rely on anaerobic metabolism for energy • Types of anaerobic metabolism • ATP-creatine phosphate (CP) system • Glycolysis
11.3 Energy for Physical Activity • Aerobic exercise—exercise for the heart • Cardiovascular conditioning or the training effect • Makes the heart stronger and increases its endurance • Improves the endurance of the lungs and the muscles along the arteries and in the walls of the digestive tract • Develops the muscles directly involved in the activity • Increases blood volume
11.3 Energy for Physical Activity • How to calculate your target heart rate range • Estimate your maximum heart rate (MHR): subtract your age from 220 • Determine your target heart rate range: multiply your MHR by 55 percent and 90 percent to find your upper and lower limits • Cardiovascular fitness goal • Work out at your target heart rate for 20 to 60 minutes
11.4 Fuels for Physical Activity • Energy-producing pathways require • Oxygen • Two muscle fuels: glucose and fatty acids • Oxygen is supplied by the lungs • Blood carries the oxygen to the muscles • Muscles and to some extent, the liver, supply carbohydrate to the muscles • Fatty acids come from fat inside the muscle and from released fat stores
The Use of Glycogen and Body Fat for Energy during Physical Activity
Fuel Use and Duration/Intensity ofPhysical Activity Insert Figure 11-6 (line chart)
11.4 Fuels for Physical Activity • Glucose use during physical activity • Glucose is stored in the liver and in the muscles in the form of glycogen (a long chain of glucose molecules linked together) • Factors influencing glucose utilization • Length of exercise session • Degree of training • Amount of glycogen stored in the muscles before exercise
11.4 Fuels for Physical Activity • Fat use during physical activity • Fatty deposits all over the body supply fat for muscles to burn during exercise • Oxygen must be present to burn fat • Rule of thumb: If you can’t talk normally, you are burning more glucose than fat; if you can sing, you aren’t burning much of anything (so speed up). • Training impact • Body is better at delivering fat to working muscles • Muscles have increased ability to use fat
Eat Well Be Well: Use It and Lose It! • A total fitness routine is needed to enhance health • Tips for sustaining a physical activity program • Check with your physician before starting • Find an exercise buddy • Do not overdo it, especially in the beginning • Do not focus on weight loss
11.5 Protein Needs for Fitness • Optimal nutrient timing before or during and after resistance training • Can minimize muscle protein breakdown • Can optimize muscle growth and repair • Refer to Table 11-3
11.6 Fluids and Physical Activity • Water and fluid replacement drinks • Plasma volume (plasma): water in the blood • Carries body heat to the skin where it can be dissipated • Water is lost through sweating and must be replaced • Athletes performing a vigorous activity must rehydrate before, during, and after exercise
11.6 Fluids and Physical Activity • Signs of hyponatremia • Severe headache • Nausea and vomiting • Muscle cramps • Bloating • Confusion • Seizure
11.6 Fluids and Physical Activity • Water and fluid replacement drinks • Choice between water and a sports drink • A preference for fitness enthusiasts • A matter of performance for endurance athletes • Carbohydrates in sports drinks • Provide an energy source for working muscles • Help maintain blood glucose at an optimum level • Help increase the rate of water absorption from the small intestine
11.7 Vitamins and Minerals for Physical Activity • The vitamins • Are the links and regulators of energy-producing and muscle-building pathways • B vitamins govern the energy-producing metabolism reactions • Needs are proportional to energy expenditure • Eating five-plus fruits/vegetables per day • Helps athletes meet recommended intakes for the antioxidant nutrients
11.7 Vitamins and Minerals for Physical Activity • The minerals • Iron is crucial for hemoglobin and myoglobin, needed for oxygen delivery • Iron supplements should only be taken under medical supervision • Sports anemia is a temporary state • An adaptation to physical training
11.7 Vitamins and Minerals for Physical Activity • Calcium, the bones, and exercise • Strength training encourages bone growth • Causes of stress fractures • Unbalanced muscle development • Bone weakness due to inadequate calcium intake • Reduced estrogen concentration which leads to bone mineral loss • Preventing weak bones • Consume adequate calcium and vitamin D throughout life
The Savvy Diner: Food for Fitness • A well-balanced diet is key to peak performance • Critical periods for the athlete • Training diet • Pre-competition diet
The Savvy Diner: Food for Fitness • Planning the diet • Develop a diet rich in complex carbohydrates and low in fat • Choose foods to provide nutrients as well as calories • Eat six or eight meals each day rather than three or four meals
The Savvy Diner: Food for Fitness • Training diet • Follow nutrition plans in the off-season • Finish meals at least 2 to 4 hours before training • A high-carbohydrate meal supports blood glucose levels during competition • Include plenty of fluids—two or more 8-ounce glasses of water or juice per meal—to ensure adequate hydration • Consume adequate protein
11.8 Spotlight: Athletes and Supplements—Help or Hype? • Scientific evidence does not support • Claims of products providing a competitive advantage • Ergogenic aids: substances that increase the ability to exercise harder • Refer to Table 11-8 • Perceived benefits may be due to the placebo effect • FDA purports the need for better regulation of amino acid supplements
11.8 Spotlight: Athletes and Supplements—Help or Hype? • Human growth hormone • Not proven to cause weight loss • Anabolic steroids can be dangerous • Energy drinks or “preworkouts” • Are not properly formulated to enhance performance • Glycogen-sparing effect of caffeine • Beneficial when exercising more than 1½ to 2 hours at a time
11.8 Spotlight: Athletes and Supplements—Help or Hype? • Questions to raise regarding an ergogenic aid • Is the promised action of the product based on magical thinking? • Does the promotion claim that “doctors agree” or “research has determined,” without clarification? • Does the promoter use scare tactics to pressure you into buying the product?
11.8 Spotlight: Athletes and Supplements—Help or Hype? • Questions to raise regarding an ergogenic aid (cont’d.) • Is the product advertised as having a multitude of different beneficial effects? • Is the product available only from the sponsor by mail order and with payment in advance? • Does the promoter use many case histories or testimonials from grateful users?
