Y khoa, dược - Chapter 9: Nutrition for physical performance

Chapter 9 Nutrition for Physical PerformanceNutrition and Physical Performance“Exercise is medicine”Physical fitnessCardiorespiratory fitnessMuscular strengthMuscular enduranceBody compositionFlexibilityEnergy Systems, Muscles, and Physical PerformanceATP-CP energy systemQuick source of ATPCellular ATP and creatine phosphateFuel for 3 to 15 seconds of maximal effortEnergy Systems, Muscles, and Physical PerformanceLactic Acid Energy SystemBreakdown of glucose to lactic acid (lactate)Doesn’t require oxygenRise in acidity triggers muscle fatigueEnergy Systems, Muscles, and Physical PerformanceOxygen Energy SystemBreakdown of carbohydrate and fat for energyRequires oxygenProduces ATP more slowlyEnergy Systems, Muscles, and Physical PerformanceTeamwork in Energy ProductionAnaerobic systemsAerobic systemsGlycogen DepletionSteady drop for first 1.5 hoursEntirely depleted ~ 3 hoursEnergy Systems, Muscles, and Physical PerformanceEndurance TrainingDecreases reliance on anaerobic systemsExtends availability of glycogenEnergy Systems, Muscles, and Physical PerformanceMuscles and Muscle FibersSlow-twitch fibersFast-twitch fibersRelative proportion determined by geneticsOptimal Nutrition for Exercise PerformanceGeneral recommendations Consume adequate energy to maintain weight and healthDaily weigh-ins are discouragedProtein recommendations 1.2-1.7 g/kgFat intake 20-35% of total energy intakeOptimal Nutrition for Exercise PerformanceGeneral recommendations Risk for micronutient deficienciesAdequate fluid intake before, during and after exercise is importantNo vitamin and mineral supplements are required if athlete consumes adequate energy from various foodsEnergy Intake and ExerciseEnergy needsFuel for trainingMaintain healthy weightSupport growth (if adolescent)May require frequent meals and snacksCarbohydrate and ExerciseHigh-carbohydrate dietsIncrease glycogen storesExtend enduranceCarbohydrate loading60–70% of calories as carbohydrateDecrease exercise intensity prior to competitionCarbohydrate and ExerciseCarbohydrate intake Before exerciseEasily digested foods/beveragesPre-exercise meals and glycemic indexMeasure food to monitor its effects, which can raise blood glucoseCarbohydrate and ExerciseCarbohydrate intake During exerciseSports drinks (4–8% carbohydrate)After exerciseReplenish glycogen stores1 to 1.5 grams carbohydrate per kg both 30 minutes and 2 hours after exerciseDietary Fat and ExerciseFat IntakeMajor fuel source for endurance activitiesHigh-fat diet not neededRecommendationsModerate fat intake: 20–35% of caloriesLimit saturated fat to less than 10% of energyAvoid trans fat as much as possibleProtein and ExerciseProtein RecommendationsAdults: 0.8 grams per kg body weightEndurance athletes: 1.2–1.7 g/kgResistance-trained athletes: 1.6–1.7 g/kgProtein SourcesFoods: lean meats, fish, low-fat dairy, and egg whitesProtein Intake After ExerciseHelps replenish glycogenDangers of high-protein intakeVitamins, Minerals, and Athletic PerformanceB vitaminsNeeded for energy metabolismChoose variety of whole grains, fruits, and vegetablesCalciumNeeded for normal muscle function and strong bonesLow-fat dairy productsAdequate intake may be a problem for femalesVitamins, Minerals, and Athletic PerformanceIronNeeded for oxygen delivery and energy productionAthletes have higher lossesLean red meats, vegetables, and enriched grainsOther trace mineralsCopper and zincAvoid high-dose supplementsFluid Needs During Extensive ExerciseExercise and fluid lossIncreased losses from sweatIncreased with heat, humidityRisk for dehydrationHydrationAdequate fluids before, during, after exerciseWater vs. sports drinksDurationIntensityEnvironmental factorsFluid Needs During Extensive ExerciseNutrition Needs of Youth in SportsPriority on growth and developmentMeals/snacks both before and after exerciseCaution: High tolerance for exercise in heatNutrition Supplements and Ergogenic AidsInclude products and practices thatProvide caloriesProvide vitamins and mineralsContribute to performance and enhance recoveryAre believed to stimulate and maintain muscle growthNutrition Supplements and Ergogenic AidsRegulation and concerns about dietary and herbal supplementsBypass FDA safety and effectiveness regulationsPossibility of product contaminationNutrition Supplements and Ergogenic AidsConvenience supplementsMeal replacements, ready-to-drink supplements, energy bars, etc.Weight-gain powdersAdd an extra 500–1,000 calories/dayAmino acidsHMB, glutamineCoenzyme Q10CreatineNutrition Supplements andErgogenic AidsCreatineAntioxidantsCaffeineEphedrineSodium bicarbonateChromiumIronGreen tea extractWeight and Body CompositionWeight gainIncrease muscle and reduce fatWeight lossLose fat and maintain muscleAvoid dangerous weight-loss practices