Module XIX – Nutrition & Exercise A. Introduction 1. Benefits of physical activity a. Improved 1) mental outlook and capacity 2) self-image 3) self-confidence b. Increased 1) lean body mass (decreased body fat) 2) bone mass 3) heart, lung and muscle function c. Reduced risk for 1) CVD (higher HDL, Lower LDL) 2) Hypertension 3) Diabetes 4) CancerModule XIX – Nutrition & Exercise 2. Components of fitness a. Flexibility b. Strength c. Muscle endurance Increased muscle function due to an increase in muscle mass d. Cardiovascular endurance Ability to utilize oxygenModule XIX – Nutrition & Exercise B. Metabolism 1. Aerobic vs. Anaerobic a. Anaerobic 1) Energy production does not need oxygen, but lactate can build up 2) Increases muscle strength and mass b. Aerobic 1) Uses oxygen for complete metabolism to CO2 2) Used for fatty acid oxidation 3) Increases cardiovascular fitnessModule XIX – Nutrition & Exercise 2. Energy Sources a. ATP and PhosphoCreatine (<5 to 10 seconds)(30s dep.) 1) ATP is the primary fuel used for muscle contraction 2) Creatine Phosphate (same as Phosphocreatine) is used as a very short term energy store to regenerate ATPModule XIX – Nutrition & Exercise b. Glucose and glycogen 1) Glucose can be used from a) intramuscular stores of glycogen b) blood 2) Use a) Supplies energy for ATP regeneration b) For intermediate lengths of time (2h) c) At intermediate or high intensity exercise 3) Type of metabolism a) Anaerobic (30 sec to 2 min) • Glucose metabolism is called Glycolysis • During high intensity exercise • Lactic acid builds up b) Aerobic metabolism (>2 min) • Complete oxidation • During low to intermediate intensityModule XIX – Nutrition & Exercise 3. Fat and fatty acids (>5 min) (60% of HRmax) a. Fatty acids can be obtained from 1) the blood from a) Albumin as preformed free fatty acids b) Lipoproteins as breakdown from triglycerides 2) inside the muscle as intramuscular triglycerides b. Use 1) Supplies energy for ATP regeneration 2) For long lengths of exercise duration (steady-state) 3) Low to intermediate intensity (with training can be very useful for higher intensity) c. Type of metabolism AerobicModule XV – Nutrition & Exercise 4. Protein and amino acids a. Use 1) Could supply up to 10% of total energy b. Type of metabolism 1) Aerobic 2) AnaerobicModule XIX – Nutrition & Exercise C. Diet and Physical Activity 1. Total energy a. Dependent on body size, type and amount of training b. See section on energy metabolism 2. Carbohydrate a. Most groups recommend greater than 55% of total energy b. Carbohydrate loading 1) Can increase muscle glycogen above normal 2) Increase exercise duration at high intensity a) Especially in untrained b) May not work for womenModule XIX – Nutrition & Exercise 3. Protein needs a. Athletes may need more (1 to 1.5 g/kg/d, 80% above RDA) (at the beginning maybe even 2 to 3 g/kg) b. Uses 1) Energy 2) Tissue growth 3) Maintenance 4) Muscle bulking 4. Fat intake A low fat diet <25% energy may not be useful 5. Pre-event meal a. Avoid a high energy diet 30 minutes before an event 1) Rich in carbohydrates 2) Low in fat and fiberModule XIX – Nutrition & ExerciseModule XIX – Nutrition & Exercise 6. Minerals a. Calcium 1) Exercise will increase calcium retention by increasing bone mass 2) The best is weight bearing b. Iron 1) Many athletes are iron deficient could be due to a) increased RBC breakdown b) sweat loss c) gastrointestinal damage (8-23% of ultra-endurance athletes) c. Magnesium Requirements may be higher due to sweat loss d. Chromium Evidence is poor on the need for chromium to help build lean body mass e. Zinc Requirements may be higher due to sweat loss f. Copper Requirements may be higher due to sweat lossModule XIX – Nutrition & Exercise 7. Vitamins a. Thiamin, riboflavin and niacin Needs are related to energy use, but most in US get more than enough b. Pyridoxine (B6) May be higher due to protein use c. Vitamin E Could be higher with oxidative stress due to exerciseModule XIX – Nutrition & Exercise 8. Water and Electrolytes a. Sweat loss 1) Composition a) Water b) Sodium c) Chloride d) Also • Iron • Zinc • Copper • other trace minerals b. Water 1) Could lose water at the rate of 2L per hour 2) Dehydration likelyModule XIX – Nutrition & Exercise c. Electrolytes Sodium, potassium and chloride loses can be replenished during the event d. Minerals Losses can be replaced after the event 9. Fluid Intake a. Fluids are essential to keep body cool b. Thirst is not a reliable indicator of need c. Two cups (500 mL, about 2 cups) per pound lost d. Type 1) Water vs. Carbohydrate/electrolyte drink 2) Any will work if consumed 3) Not large amount before (about 250 ml) 4) Sport drinks beneficial during exercise lasting > 60 minutes a) Maintain blood glucose levelsModule XIX – Nutrition & ExerciseModule XIX – Nutrition & Exercise D. Female Athlete Triad 1. Female athletes who train strenuously a. Amenorrhea b. Disordered eating behaviors c. Osteoporosis (Stress fractures) 2. Common among adolescent girls, especially dancers, gymnasts and long distance runnersModule XIX – Nutrition & Exercise E. Ergogenic Aids and Steroids 1. Carnitine a. Used during fatty acid oxidation b. Not usually an essential nutrient c. May be useful for aerobic exercise 2. Creatine a. Creatine is phosphorylated to Phosphocreatine b. Phosphocreatine used during short term c. Supplementation may be useful in very specific cases (body building)Module XIX – Nutrition & Exercise 3. Caffeine a. Only works with non caffeine drinkers b. Will increase energy available during exercise 4. Growth Hormone a. Not a steroid hormone b. Will increase muscle mass c. Drawbacks 1) weaken heart walls 2) can lead to premature deathModule XIX – Nutrition & Exercise 5. Anabolic Steroids a. Synthetic and natural b. Can mimic effects seen in adolescent with muscle mass growthModule XIX – Nutrition & Exercise c. Drawbacks are enormous 1. Extreme aggression 2. Breathing difficulty 3. Heart disease 4. Blood clots 5. Liver tumors (possible