Nutrition and Physical Activity

1. Nutrition and Physical Activity Chapter 13

2. Fitness • Depends on physical activity and exercise (not body type!) • Regular physical activity • Promotes health • Reduces risk of developing many diseases • Heart disease • Cancer • Stroke • Diabetes • Hypertension

3. More Benefits of Fitness • Restful sleep • Nutritional health • Optimal body composition • Optimal bone density • Resistance to infectious diseases • Lower incidence of anxiety & depression • Lower risk for some types of cancer • Strong circulation & lung function • Stress reduction • Cortisol reduction • Strong self image • Lower risk of dementia

4. How much should I do? • Highly individual • Just 15-20 min/day starts to reduce disease risk • Minimum for optimal health: 2.5 hrs moderate or 1.25 hrs vigorous activity • Not an upper limit! • Good to spread out over the week • How much is too much?

5. Developing Fitness • Minimizing risk of overuse injuries • Be active all week • Use proper equipment and attire • Use proper form • Include warm-up and cool-down activities • Challenge your strength and endurance a few times a week • Mix it up! • Pay attention to body signals

6. Developing Fitness • Muscle conditioning • Fit muscles use oxygen efficiently • Increased mitochondria and vasculature • Reduces heart’s workload • Burns fat longer • Balanced fitness program • Activities you enjoy doing • Addresses all aspects of fitness • Strength, endurance, flexibility • Each has specific benefits

7. Resistance Training • Purpose • Build muscle mass • Increases metabolism! • Develop and maintain muscle strength, muscle power, and muscle endurance • Benefits for prevention of chronic diseases • Maximizes and maintains bone mass • Improves posture & reduces risk of back injury

8. Nutrition & Physical Performance • Performance and recovery both enhanced by optimal nutrition • We need all essential nutrients to power movement • 3 energy systems: • ATP-CP, lactic acid, and oxygen • All 3 systems always active and work together • ATP-CP (creatine phosphate) • Stores of ATP and CP only power muscles 3-15 seconds • Muscle and liver glycogen needed to continue contraction

9. Creatine Phosphate • Popular supplement (ergogenic aid) • Studies show improvement in muscle strength and power • No benefit for aerobic training • Possible side effects: • Weight gain (water retention) • GI symptoms: nausea, diarrhea, abdominal pain • Rash, anxiety, headache, fatigue • Not appropriate for people with kidney issues • Should be avoided in children, adolescents, pregnant women, nursing mothers, diabetics

10. Anaerobic vs. Aerobic • Anaerobic activities and fatigue • Lactic acid energy system • Anaerobic glycolysis leads to drop in pH • Impairs glycolysis, inhibits binding of calcium • Aerobic activities and endurance • Oxygen energy system • Oxidative metabolism of energy nutrients • Increased blood flow to muscles: oxygen! • Produces much more ATP, but at slower rate • Uses glucose and fatty acids

11. Endurance • As long as ATP supply meets energy needs, activity can continue • Rate/intensity of activity influences energy system used • Anaerobic exercise: CP and glycogen rapidly depleted • Level of training highly influences shift to anaerobic metabolism • Number of mitochondria and efficiency of oxygen delivery increase with training

12. Glucose Use During PA • Exertion • Liver breaks down glycogen • Release glucose into bloodstream • Muscles use glucose and stored glycogen • Muscle fatigue when glycogen is depleted • Glycogen storage: limited • Intensity of activity • Impacts how long glycogen will last • CHO post-workout restores glycogen, spares muscle tissue

13. Protein Use & PA • Not a significant part of fuel mix for most • Used in muscle building • Synthesis suppressed during activity; accelerates afterward • High-quality protein consumption • Enhances muscle protein synthesis • What is a high-quality protein? • Protein needs are higher for endurance and strength athletes • Need adequate CHO, as well…why?

14. Recommended Protein Intakes for Athletes • Endurance athlete: 1.2-1.4 g/kg body weight • Strength athlete: 1.6-1.7 g/kg body weight • Everyday adults: minimum of 0.8 g/kg body weight • Max. usable amount for adults: 2.0 g/kg body weight • Risks of excessive protein intake • Dehydration • Mineral losses

15. Vitamins and Minerals to Support Activity • Roles in supporting activity • Assist in releasing energy from fuels • Transport of oxygen • Multiple vitamins and minerals, as well as protein, involved! • Supplements • Vast majority do not enhance performance of well-nourished people

16. Fluids and Electrolytes to Support Activity • Fluid replacement via hydration • Hydrate before activity • Drink extra fluid in the days before event • Rehydrate during and after activity • Fluids for everyday, active people • Plain, cool water • Fluids for endurance athletes • May benefit from mineral and CHO-containing beverages

17. Sports Drinks vs. Water • Sports drinks • Hydration is critical to optimal performance • Water is best for most people • Sport drinks offer the following • Fluid • Glucose • Sodium and other electrolytes • Some prefer the flavor

18. Dietary Strategies for Active People • Hydrate • Thirst is a late signal of need • Choose nutrient-dense foods • Vitamins & minerals • Consume adequate energy • Need all energy-yielding nutrients • CHO, protein, and fat • Meal frequency and balance • Stable blood glucose means stable energy levels • Optimal maintenance of lean tissues

19. Timing of Meals • 30 min-1 hour pre-workout • Protein-based snack or small meal • Timing is individual • Not for everyone! Depends on GI picture. • During workout • Sip water • Post-workout • Best time to consume CHO-rich foods • Include protein! Balance. • Fitness goals: highly individual! • Timing strategies vary depending on goal • Ex: carbohydrate loading