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

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

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

Physical Activity Guidelines for Americans

Intensity of Physical Activity

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

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

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

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

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

Delivery of Oxygen by the Heart and Lungs to the Muscles

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

The Effect of Diet on Physical Endurance

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

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

Activity Duration, Glucose Use, and Glycogen Stores 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

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

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

Nutrients of Concern Vitamin E Iron 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 Activity Breathing and sweating Dehydration Sweat and temperature regulation Heat stroke Potentially fatal Reduce risk Hypothermia Symptoms

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

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

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

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

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

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

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

Hormone 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 Hormone Drugs