Chapter 14: Nutrition and Physical Activity: Keys to Good HealthWhat Fuels our Activities?- Carbohydrates, fats, and even small amounts of proteins- ATP: very limited, keeps muscles active for only 1-3 secondsThe ATP-CP Energy System Uses Creatine Phosphate to Regenerate ATP- When more energy is needed, a high-energy compound, creatine-phosphate, can be broken down to support the regeneration of ATPo Anaerobic reaction(without oxygen) o Maximal physical effort for about 3-15 secondsThe Breakdown of Carbohydrates Provides Energy for Both Brief and Long Term Exercise- The most commons source of glucose during exercise comes from glycogen stored in the muscles and glucose found in the blood- For every glucose molecule that goes through glycolysis, two atp molecules are produced - The primary end product of glycolysis is pyruvate - The major advantage of glycolysis is that it is the fastest way to generate atp for exerciseo Generally less than 3 minutes- One glucose molecules going through aerobic metabolism yields 36-38 atp for energy, whereas the anaerobic process yields only about 2 atp molecules- The cori cycle: the metabolic pathway by which excess lactic acid can be converted into glucose in the liverAerobic Breakdown of Fats Supports Exercise of Low Intensity and Long Duration- When we refer to fat as a fuel source, we mean stored triglycerideso LONG TERM ACTIVITY- Fat is an abundant source, even in lean people- Fat provides 9 kcal or energy per gram, more than twice as much energy per gram as carbso Disadvantage, the process is relatively slow- Primary source of energy during rest, sitting, and standing in place Amino Acids Are Not Major Sources of Fuel During ExerciseVigorous Exercise Increase Energy Needs- Athletes generally have higher energy needs than moderately active or sedentary people- The energy needs of male athletes are high than those of female athletes Carbohydrate Needs Increase for Many Active People- Amdr for carbohydrates is 45%-65% of total energy intake- Muscle glycogen storage during the first 4-6 hours of recovery - In general , complex, less-processed carbohydrate foods such as whole grains and cereals, fruits,vegetables, and juices are excellent sources that also supply fiber, vitamins, and minerals - Carbohydrate Loading: glycogen loading, involves altering both exercise duration and carbohydrate intake such that it maximizes the amount of muscle glycogeno Do not always improve performance o Side effects: diarrhea, heavy, bloated, sluggishModerate Fat Consumption Is Enough to Support Most Activities- When reach a physical trained state, able to use more fat for energy. Better “fat burners”o Increase in the number and activity of various enzymes involved in fat metabolism , improved ability of the muscles to store fat, and improved ability to extract fat from the blood for use during exerciseo Spare carbs to use during prolonged intense training or competitionMany Athletes Have Increased Protein Needs - Those who are already trained need less protein than those who are initiating training- Zone dieto 40-30-30 diet, 40% carb, 30% fat, 30% protein Not true- People of all fitness levels can consume more than enough protein without the use of supplements or specifically formulated foodsRegular Exercise Increases Our Need for Fluids- Functions of watero Lubricant that bathes the tissues and cellso Transport medium for nutrients, hormones, and waste productso And important component of many chemical reactions, energy production!o Structural part of body tissues such as proteins and glycogeno Vital component in temperature regulation- Heat sycope: dizziness that occurs when people stand for too long in the heat and the blood pools in their lower extremities rather than fully supplying their brains- Heat cramps: muscle spasm that occur during exercise or even several hours after strenuous exercise- Heat exhaustion: excessive sweating, weakness, nausea, dizziness, headache, and difficulty concentrating- Heat stroke: hot, dry skin, rapid heart rate, vomiting, diarrhea, increase in body temperature- Avoid losing more than 2%-3% of body weight during exercise- Longer than 1 hour in any weather, sports beverages containing carbs and electrolytes are recommendedInadequate Intakes of Some Vitamins and Minerals Can Diminish Health and Performance- When individuals train vigorously for athletic events, their requirements for certain vitamins andminerals may be alteredo B-vitaminso Calcium and the female athlete triado Iron Iron needs cannot be met through the diet and supplementation is
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