Exercise and Sports Nutrition
Exercise and Sports Nutrition HPER 3970
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This 61 page Class Notes was uploaded by Liam O'Kon on Wednesday September 30, 2015. The Class Notes belongs to HPER 3970 at Western Michigan University taught by Christopher Cheatham in Fall. Since its upload, it has received 62 views. For similar materials see /class/216831/hper-3970-western-michigan-university in Health Sport And Exercise Science at Western Michigan University.
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6242009 General Principles of Nutrition Chapter 1 HPER 3970 Summer 2009 Dr Cheatham W What is Nutrition 1 The total of the processes of ingestion digestion absorption and metabolism of food and the subsequent assimilation of nutrient materials into the tissues Sports Nutrition The integration of the principles of nutrition to the optimization of physical performance 6242009 W Functions of Food Six categories of nutrients Carbohydrates CHO Fats Lipids Protein PRO Vitamins Minerals Water Macronutrients Daily intake gt a few grams CHO Fats PRO Water Micronutrients Daily intake lt 1 gram day Vitamins Minerals Trace Elements W Function of Foods Promotion ofgrowth and development PRO calcium phosphorus Provision ofenergy Mainly CH0 and Fats Regulation of metabolism Vitamins minerals proteins Role of enzymes in cellular reactions 6242009 W Dietary CHO ii Structure CHZO 121 CH20n Example Glucose C6H1206 Types of CHO Monosaccharides Basic unit ofCHO Glucose fructose galactose Glucose is only CHO that can be oxidized by muscle Fructose and galactose must be converted to glucose before they can be oxidized El Dietary CHO Types of CHO cont d Disaccharides Combination of two monosaccharides Also called simple sugars Sucrose lactose and maltose Sucrose most abundant disaccharide in diet 20 25 Dietary Intake Lactose present in milk Maltose present in beer cereals W Dietary CHO 1 Types of CHO cont d Oligosaccharides and Polysaccharides Oligosaccharides 39 mono Polysaccharides gt10 mono Polysaccharides Starch Complex CHO Seeds rice corn grains 50 of our daily intake of CHO Glycogen Storage form of CHO in body Liver N 80 to 100 grams Muscle N 300 to 900 grams Fiber Soluble versus insoluble Can influence gastric emptying and absorption Fl CHO Structure 1 a a l 6242009 6242009 W Functions of CHO if Main function is providing energy Especially during highintensity exercise Stored in muscle and liver glycogen Blood glucose Only fuel source for CNS brain spinal cord Normal values 5 mmorL lt 3 mmolL start to see weakness hunger dizziness shivering Hypoglycemia Hyperglycemia F CHO Intake Typical Intake Africa 80 of calories Western World 4050 of calories Athletes might need more 60 In Western diets 50 ofCHOintake is simple sugars Linked to CHD Obesity Diabetes Dietary Fiber Recommended 13g1000kcal20 35 gday Western Diet 1415gday E Dietary Lipids Compounds that are soluble in organic solvents such as acetone ether and chloroform Structure CH3CH214COOH Palmitic Acid CH3 Methyl Group COOH Carboxylic Acid Three classes of lipids Simple lipids Compound lipids Derived lipids Triacylglycerols or triglycerides are the most abundant dietary lipid E2 Dietary Lipids Fatty acids Differ in length and composition 6 carbons or less SCFA 8 or 10 carbons MCFA 12 or more carbons LCFA Further classification of FA s saturated no double carbon bonds Unmhnmed1ormomdoumebonm Monounsaturated 1 double bond Polyunsaturated gt 1 double bond 6242009 1 E Dietary LlpldS Triacylglycerols are usually incorporated into the core of a lipoprotein Chyomicrons VLDL s LDL s DL d HDL s E Dietary Lipids 6242009 6242009 E Dietary Lipids TablelJ Classesoilipids 39 lipid Examples Simple lipids Compoundlipids a Derivedl39rpids ii Ki Dietary Lipids Table 12 Di mm Pally um in and rim Nomi 7 7 FA Double bond mum nam Chunks formula P L I i r w 6242009 Ei39 Functions of Lipids Fuel source especially during prolonged exercise Protection ofvital organs 2 to 4 is stored around organs Fat soluble vitamins ADEK Phospholipids and cholesterol are important parts of cell membranes Cholesterol is an important component of bile Cholesterol is precursor for many hormones Eicosanoids cell regulators Fat suppresses hunger Makes food taste better and appear more attractive El Lipids As Fuel Oxidizable lipid fuels include FA s IMTG Chylomicrons VLDL Transport Functions VLDL TG s from liver to adipose tissue and muscle HDL Cholesterol from peripheral tissues to liver So chylomicrons and VLDL play role in exercise metabolism 6242009 Fl Fat Intake Kl 38 of total calorie intake lt 30 recommended 95 of fat intake is in the form of TG s 100 to 150 gramsday 34 from plant 66 from animal Saturated fats account for 15 of total calorie intake Saturated fats are related to high cholesterol levels and CAD Trans fatty acids more highly related to high LDL levels Ej Trans Fatty Acid Structure H H H H Cis double Trans double 11 13 15 17 1 3 5 7 9 10 ElaidicaCid181 COOH Wt 12 14 16 18 2 4 6 8 134 6 7 91012 14 18 18 COOH 2 5 8 11 13 15 17 Columblnic acid 183 nBc 90 131 5 Trans 391 11 rind have I Slllklllllv LllllL lifl l i lll39li i ill Loriliiiii iiirriii llinii cis law ll ll l3 l Figure 39l mu ore irmunizeo oz 3 iiiuiiwm l l39l llnl luii 10 W Dietary Protein Amino acids are the building blocks ofall protein PRO Structure Classification 20 different AA s Carbon atom with four groups Hydrogen Amino group w Nitrogen carboxylic acid group COOH side chain Nonessential AA 12 AA s Can be synthesized by the body Essential AA 8 AA s Cannot be synthesized bythe body Must be provided bythe diet Proteins that contain all 8 essential AA s are called Complete Proteins that are deficient in one or more essential AA s are called Incomplete El Dietary Protein 6242009 J V4 Dietary Protein 1 Nonessential Essential amino acids amino acids Hijhrlihe lso elf he r G ulumim Byline Fro iwe Sglille lyiosincv Figure 17 W Lllbpl fliiill lti llllll39 A l 7 l l W Dietary Protein Function of PRO Role in metabolism Precursor for synthesis of body proteins Precursor for metabolic mediators and regulators of biological activity Hormones DNA RNA enzymes neurotransmitters Cell structure Membranes organelles muscle skin hair Can provide cellular energy Intake RDA 08 to 12 gkg BW 80 to 100 gramsday Athletes might need more Western diet usually more than adequate 6242009 6242009 Ei39 Water Facts Adult body is N 60 H20 Blood N 90 H20 Muscle N 75 H20 Adipose Tissue N 5 H20 Function Transport nutrients Protection Helps to regulate body temperature Sweat blood volume Biological reactions Lubrication cleansing cushioning Ej Water Water Deficiency Dehydration Loss of 3 of total body weight decrease in blood volume and exercise performance capacity Loss of 5 total body weight confusion disorientation gt 10 Lifethreatening Intake N 20 to 28 Lday Recommended 1mL4 kl ofenergy expended 1 mLkcal Exercise especially in hot environments may increase need up to 15 Lday 6242009 Ki Vitamins Minerals Trace Elements Vitamins are organic Minerals and trace elements are inorganic 13 known vitamins Function Regulators for the metabolism of foods Cofactors for chemical reactions Strong relation to health Classification Vitamins WaterSqubIe and Fat Soluble Minerals Macrominerals gt100 mgday Microminerals Trace Elements lt 100 mgday E Vitamins Minerals Trace Elements Water soluble Fat soluble i ltmorrme v llei A 39laollovinl Vitamin D l quotv it och v ilcmin E 1I 7OCOpliEiOll hmhi B loyhdomel Vitamin K E imn39m B Elwin litrlolnen l on ifh 6242009 W Alcohol Ethanol if 7 kcalgram Not necessaryin diet Most widely abused drug Negative health impacts liver 1 in 20 deaths related to alcohol Positive health impacts Moderate consumption Increase in HDL Decrease in TG s Decrease stress Antioxidants El Essential Nutrients Nutrients that are essential for human life Criteria Substance is required in the diet for growth health and survival Absence in diet results in signs of deficiency disease and death Growth failure and characteristic signs of deficiency are prevented only by the nutrient and not by other substances Intake below a critical level results in deficiencies in the growth response as is proportional to the amount consumed Substance is not synthesized by the body W Essential Nutrients 39 L th lvl ii fii iiif l uli i39dt lvii39 eczl Ll39iC Linn Ei l39ll i i in w n cw Chance Figure l9 39E39Je iu l v ii emu l9 iiii erquot W Essential Nutrients Recommended Intake DRI Dietary Reference Intake EAR Estimated Average Requirement Amount of nutrient that is deemed sufficient to meet the needs of the average person RDA Recommended Dietary Allowance Level of intake for essential nutrients determined on the basis of scientific knowledge to be adequate to meet the known nutrient needs of practically all 97 healthy persons Age and gender specific Does not take into account disease environmental stress or other factors RDA EAR 2 STDEVEAR 6242009 6242009 W Essential Nutrients 1 Recommended Intake cont d AI Adequate Intake Level of nutrient deemed adequate when there is not sufficient scientific data to establish an EAR UL Tolerable Upper Intake Level Maximum level of daily intake that is unlikely to pose health risks DV Daily Value Recommended daily intake of a nutrient Has replaced RDA Urlglnally developed for food labels Based on two sets of reference RDI DRV Daily Reference Value More of a global recommendation that is supposedly applicable to most individuals regardless of age gender etc W Essential Nutrients If I J i J m gt i 4 x 3 QESEWHE ZGI J 3 7 I a rw 3 A v a g y eIlmaance E v 7 l as R 3 quot ly Z x I 5 K 9 I l Increasing Intake Figural l0 39 a 39 W W 6242009 r4 Essential Nutrients 11 The Food Guide Pyramid Old A These symbols show 315 I W Essential Nutrients 1 The Food Guide Pyramid New MyPyramid Mvaan 6242009 W Reading Food Labels 1 Macaroni 8x Cheese Nutrition Amwnt vu Sawing rig m Ki Assessing Nutrient and Energy Intake Useful for several reasons Group of athletes can be Studied and the data can be used in conjunction with biochemical and anthropometrical data to assess the adequacy of the diet Used in conjunction with medical reports to explain the incidence or prevalence of health problems Education Aid with nutritional advice or intervention programs 6242009 E Assessing Nutrient and Energy Intake table 16 Methods to Estimate Nutrient Intake 1 7 ft i W 3 Assessing Nutrient and Energy Intake Retrospective methods ZAron watt 1 fwd 39vequewcy N97 hater A 20 722009 Carbohydrates Chapter 5 HPER 3970 Summer 2009 Dr Cheatham 3 Introduction A Since the beginning ofthe 20th century CHO have been shown to be important for exercise performance Availability of CHO as a substrate for skeletal muscle contraction Substrate forthe CNS Thus CHO is an extremely important component of an athlete s diet and various strategies have been employed CHO feeding before exercise Replenish muscle and liver glycogen stores Maintain blood glucose levels and high rates of glucose oxidation from the plasma 722009 Ei39 History Focus on Research Krogh and Lindhardt 1920 High CHO vs High Fat Diet threedays prior to competition 2hr cycling Subjects fatigued much quicker with highfat diet RERROalso changed Levine Gordan and Derick 1924 Measured blood glucose in 1923 Boston Marathon participants Blood glucose was greatly declined after the race Oneyear later researchers had some ofthe participants ingest CHO during the race Performance greatlyimproved E History Focus on Research Dill Edwards and Talbott 1932 Tested the effects of CHO on their dogs Joe and Sally Without CHO dogs could run 46 hrs With CHO dogs could run 1723 hrs Christensen 1932 As exercise intensity increases the proportion of energy coming from CHO also increases Bergstrom and Hultman 1966 Introduction of muscle biopsy technique Realized the importance of muscle glycogen on performance and the effects of diet on muscle glycogen Ei History Focus on Research 5 Role of CHO Muscle Glycogen Muscle glycogen is a readily available energy source for the working muscle Values 1216 g kg vvvv 300400 g Rate of utilization is highly dependant on exercise intensity Low to moderate intensity Most ofthe energy can be obtained from the oxidation of acetylCoA from CH0 and Fat Moderate to high intensity Energy needs can not be met solely by the oxidation of CHO blood orfat Muscle glycogen utilization increases Anaerobic energy mostly derived from breakdown of muscle glycogen 722009 722009 5 Role of CHO Muscle Glycogen Muscle glycogen mmollkg ww I I I I I I I 0 30 60 90 120 150 180 Exercise time h Figure 51 inqr V0 mix AMUIV 39l mu l qr mun meilLiI39IIIw l I l I I I mI s39ic Ej Role of CHO Liver Glycogen Main role of liver glycogen is to maintain a constant blood glucose level 4045 mmoIL 60100 mgdL The liver is often referred to as the quotGlucoregulatorquot or quotGIucostatquot Liver weighs 15 kg 33 lbs and has 80110 g of glycogen Glucose broken down by the liver is released into the circulatory system Hepatic glucose output Endogenous The liver has a much higher concentration ofglycogen than muscle but a lower absolute amount 722009 Ki Role of CHO Liver Glycogen WW Figure 52 l xl l l l 39 wmz ll y l l r W Ell Role of CHO Liver Glycogen Effects of exercise on liver glycogen Liver glycogen decreases around 50 after 1 hr of exercise at 75 VOzmax At rest Glucose output is about 150 mgmin 60 from breakdown of liver glycogen 40 from gluconeogenesis During exercise Glucose output is about 1 g 1000 mgmin 0 gt90 from liver glycogen 722009 Fl Role of CHO Regulation of Glucose Concentration if Blood glucose is normally maintained within a very narrow range Hormones playa key role Insulin Promotes uptake and storage of glucose Glycogen synthase Activity Glycogen Phosphorylase Breakdown ofglycogen Glucagon Breakdown of liver glycogen Catecholamines Reduces insulin secretion Increase glycogen breakdown Other Hormones Cortisol growth hormone F Role of CHO Regulation of Glucose Concentration During Exercise Increase in catecholamine release reduces insulin secretion by pancreas Muscle glucose uptake is enhance by contraction stimulated transport During high intensity exercise gt 80 VOZmax glucose release by liver might exceed uptake by muscle Hyperglycemic response During prolonged exercise liver glycogen may be depleted and the rate of glucose production may be insufficient to compensate for glucose uptake by muscles and other tissues 722009 W CHO Before Exercise if CHO days before competition Replenish muscle glycogen stores CHO hours betore competition Optimize liver glycogen stores Carbohydrate in the days leading up to competition bupercompensatlon Protocol Glycogen depleting exercise bout Day 1 HighPRO HighFat Diet Days 123 A second exhausting exercise bout Day 4 HighCHO Diet Days 456 El CHO Before Exercise Carbohydrate in the days leading up to competition cont d This classic supercompensation protocol seemed to optimize performance However there are some negatives Hypoglycemia during lowCHO diet Practical problems GI problems Poorrecovery 1 week of no training Increased risk ofinjury Mood disturbances 722009 W CHO Before Exercise 1 Carbohydrate in the days leading up to competition cont d Because of the negatives of this protocol a more moderate protocol has been used Training was tapered the six days before competition rest on last day 50 CHO diet for 1St 3days of taper High CHO Diet 70 for last 3days of taper Effects Muscle glycogen levels were high for competition Minimization of negative sideeffects Time to exhaustion increased around 20 Time to complete a set task decreased N 23 o Application is sport specific Fl CHO Before Exercise 1 39lCC 30 Carbohydrates Carbohydrates In diet 39 0 L709 7 at 1 Little 45 5 4 3 2 1 I Com ltlon Corn itiun Training Training Much Much a Figure 53 of quote v x quot 722009 r4 CHO Before Exercise 1 Glycogen concentration gkg ww muscle gt Before Halftime l End Hiyawhalwamlemay l l5 A l l l xluimuldlul l 7 l l 0 Distance covered l lsihulfim 2nd half m l Walk Sprint 0 nglvcorbohydroledlel l o loo 5000 l 2 l 24 l lm39lmlrhci r W i Boo moo so in Wm will we an m illdulan lm39dnirrnliln mm exam l E CHO Intake 35 Hours Before Exercise Athletes should have the last fairly large meal 35 hours prior to exercise or competition Might increase muscle glycogen Will increase liver glycogen especially after an overnight fast 140 to 330 grams of CHO However this ingestion of CHO will also cause A transient decrease in blood glucose at the onset of exercise Increased CHO oxidation and glycogen breakdown Blunting of FA mobilization and oxidation These effects do not seem to have a detrimental effect on performance 722009 r4 CHO Intake 3060 min Before Exercise CHO ingestion preexercise Large rise In plasma glucose and insulin Onset of exercise rapid decrease In plasma glucose Liver glucose output inhibited Plasma FFA mobilization In inhibited Role ofglycemic index Increase in blood glucose and Insulin in response to ingestion of a food Influence on performance Essentially no impact on performance Ki CHO Intake 3060 min Before Exercise Table 52 olymnic tum GI and remit M41 2 mquot lAvnIIuhlo cup M GI lsinlg cmhydmms saving 722009 W CHO During Exercise CHO feeding during exercise of about 45 minutes or longer can improve endurance capacity and performance Maintaining blood glucose and high levels of CHO oxidation Glcoven s arinv Promoting glycogen synthesis during exercise Affecting motor skills Affecting the CNS W CHO During Exercise Feeding Strategies and Exogenous CHO Oxidation A greater contribution of exogenous fuel sources spares endogenous sources and may influence performance lid Fl CHO During Exercise Feeding Strategies and Exogenous CHO Oxidation cont d Feeding Schedule Very little effect e bolusvs intervals Amount of CHO The optimal amount is likely to be the amountthat results in maximal exogenous oxidation rates without causing GI problems Recommended 70 ghr 7 5g is 25 57 55 i 39 A K 0 D A I ri x A g 39 5 IA 7 J Carbohydrate ingestiua late lglmlnl figure 55 F CHO During Exercise All Feeding Strategies and Exogenous CHO Oxidation cont d Type of CHO Different types of CHO result in different absorption rates Recommended glucose fructose mix Exercise Intensity Exogenous CHO breakdown increase with exercise intensity Levels off between 5164 VO Metabolic effect of CHO during Exercise Early Increase in insulin and blunting of FFA Zmax Later Less ofan effect 722009 W CHO After Exercise 1 Main purpose is to replenish depleted stores of liver and muscle glycogen Rapid phase Immediately postexercise few hours Slow phase gt3 hours postexercise PostExercise Feeding Timing of CHO Intake Immediately postexercise l T 2mer lit y OSlEXE39E SC39 m 3 1 5 n 4 Glycogen synthesls mmalikg ww p 3 0120 nun 120240 mln 7 Figure 510 W CHO After Exercise 1 PostExercise Feeding cont d Rate of CHO ingestion N 14 gmin Type of CHO Glucose preferred highGI foods Protein and CH0 together PRO may increase glycogen synthesis Solid vs Liquid No difference Muscle Glycogen Diet and Repeated Days of Training Diet can influence recovery between repeated bouts 722009 r4 CHO After Exercise u D Carmnym m mum mm 13m 51 I T I E g 1 i 1 a 39T I z r 0 1199QO 39 Mgmyh Law I 1191ng CHO CHOVOJ CHO 210le w kghFRO ngmm V CHO After Exercise 3 g 500 High CHO mm 5 339 400 quot 393 U gt 51 300 l o 3 200 g 1 Law CI IO dm 1 g 00 Ar 2 l I l D 7 r 4 0 w 24 35 M3 so 72 I 151 km run Time h gure 513 gtv 7 722009 722009 Ei39 Overall Recommendations To optimize muscle glycogen Moderate Intensity Training 57 gkg bwday Prolonged Hard Training 710 gkg bwday Very Prolonged Hard Exercise 1013 gkg bwday Choose highGI CHO foods Consume sports drink to provide a convenient source of CHO in the first hour after exercise when appetite is suppressed 762009 Fat Chapter 6 HPER 3970 Summer 2009 Dr Cheatham Ei Availability of Fat Table 6 Availability af Subsh39ufes in the V Substrate Carbohydrmu Welghf kg Energy 10 kEal 762009 E Fat Metabolism During Exercise Two main sources Adipose tissue Muscle triglycerides OthersourceVLDL Figure of Ej What Limits Fat Oxidation Although fat stores are large using these fats can be difficult Lipolysis 39 Hormone Sensitive Lipase HPL Active and Inactive Forms Role of hormones 39 Reesterification Removal of FA s and Transport in the Blood 39 Blood flow to adipocyte 39 Albumin concentration and binding sites Transport of FA s into the Muscle Cell 39 Specific carrier proteins FABPPM Fatty Acid Binding Protein FATCD36 Protein FABPC Ki What Limits Fat Oxidation Figured 39 gt3 v 7 r 7 W 77 gt7 Ki What Limits Fat Oxidation Intramuscular Triglycerides x i i i i I 1 1 i 762009 Ki What Limits Fat Oxidation Transport of FA s into the Mitochondria AcyICoA synthetase Carnitine Palmitoyl Transferase and II inner ociionarrai membrane ochond riai main iaxidaiinn 1 acyiCOA CoASi I re 66 u my m iquotIJ39 1 Ei What Limits Fat Oxidation Beta Oxidation Fatty AcyICoA is spit into 2carbon AcetyICoA which can then be used to synthesize ATP Fatty acylCDA Falty acylCoA ll2 AcnlylCoA 2 carbons Figure 67 39r B LI L39Z39Z39 1232 762009 Ei39 Fat as a Fuel During Exercise Fat utilization at rest and during exercise At rest most ofthe energy requirements are met bythe oxidation of FA s With exercise Rate of lipolysis increases During moderateintensity exercise rate of lipolysis can increase 3fold During first 15 min of exercise Plasma FA levels decrease After15 min Plasma FA levels increase Fat Oxidation and Exercise Duration Fat oxidation increases as duration increases Most likely due to a decrease in muscle glycogen stores E3 Fat as a Fuel During Exercise Fat Oxidation and Exercise Intensity Fat predominant fuel at lower intensity CHO predominant fuel at higher intensity Maximal rates of fat oxidation usually occur around 6263 VOZmax Exercise at 25 VOZmax Low Intensity Mostly plasma FA s are oxidized Exercise at 65 VOZmax Moderate More intramuscular triglycerides 50 o Exercise at high intensity Fat oxidation decrease although lipolysis is high Blood flow to adipose tissue Lactic acid leads to reesterification 762009 762009 Ki Fat as a Fuel During Exercise o o Jgt 0 1 I 03 Fat oxidation gminquot Exercise intensity Ail02mm Figure 68 W mnl Ell Fat as a Fuel During Exercise Fat Oxidation and Aerobic Capacity With training metabolic adaptation to shift to a greater utilization of fat and thus glycogen sparring Increased mitochondrial density Increased capillary density Increased FABP concentrations Increased CPT concentrations Lipolysis not affected much At least at adipose tissue Lipolysis of intramuscular triglycerides may increase 762009 Ki Fat as a Fuel During Exercise 45 Unlrained 340 Trained E 35 3 30 E 3 25 Q E 20 9 15 E a 0 l 5 0 Rests Exercnse 30 0 3390 60 90 do 150 180 2f0 24o Timemin Figure 6 Whivw39rfg f i runs a if irrivwni and nnrininm i39 l E Fat as a Fuel During Exercise Fat Oxidation and Diet High CHO LowFat Lower rates of fat oxidation Low CHO HighFat Higher rates of fat oxidation Longterm effects of diet Response to CH0 Feeding CHO feedings result in a decrease in fat oxidation 30 Role ofinsulin Decreasedlipolysis Inhibitory effect on transport of FA s into the mitochondria CPT Ki Regulation of CHO and Fat Metabolism The rate of CHO utilization during prolonged strenuous exercise is closely linked to the energy needs ofthe working muscle Fat utilization during exercise is not as tightly regulated Mainly influenced by fat availability and the rate of CHO utilization 50 I lulralrpln D Control Muscle glycogen lmmolkg w w nelore Alter Exerclse at 70V01mex FigurebJJ E r 1 y 1 Ki Fat Supplementation and Exercise Eating fat before or during exercise has been studied as a methodtoincreaseFAavaHathyandincreasefatouda onin order to reduce muscle glycogen breakdown m mndngcmmTGs Digestion and absorption is slow Not recommended during exercise IMMndMMMm mmms Popular as supplements Decrease body fat Cannot be stored in the body Used as an alternative fuel source Inges on othh OHS Longchain omega3fatty acids Thought to improve membrane function 762009 762009 Vi Effect of Diet on Fat Metabolism and Performance it Fasting Has been proposed as a way to increase fat utilization and spare I coven and improve exercise performance No effect on lowintensity performance Negative effect on moderate and highintensity performance Euglycemia probably not maintained Metabolic acidosis Lower liver glycogen stores Effects of a shortterm highfat diet Impaired fatigue resistance Decrease in muscle glycogen stores May also increase muscle triglyceride breakdown F Effect of Diet on Fat Metabolism and Performance Effects of a longterm highfat diet More discrepant results The idea is that a highfat diet will make the body adapt to better utilize fat But glycogen stores will be lower Therefore studies examined the effects of a longer duration highfat diet followed by a highCHO diet Consensus is that performance is decreased by a highfat diet or at least does not improve as much compared to a highCHO diet Probably more of a negative effect at higher intensity exercise r4 Effect of Diet on Fat Metabolism and Performance A saw no r haul on 762009 6242009 Energy Chapter 3 HPER 3970 Summer 2009 Dr Cheatham W What is Energy 1 Many different forms Light chemical mechanical In physiology Energy represents the capacity to do work mechanical energy Work Force x distance Power WorkTime Energy Expenditure Energy expended in kiloloules kl or kilocalories kcal per unit of time to produce power 6242009 E What is Energy During the conversion of one type of energy to another no energy is ever lost ie chemical energy can be converted to mechanical energy heat Humans are not very efficient During cycling energy only 20 ofthe chemical energy is converted to power The rest is converted to heat Helps to maintain body temperature but can also result in increases in internal body temperature E2 What is Energy Units of energy Often expressed as calories or Joules 1 calorie the energy needed to raise the temperature of 1 gram 1 mL of water 1 C 18 F Example Food containing 200 kcal has enough energy to raise the temperature of 200 L of water 1 C Joule SI Unit ofenergy 1 moves a mass of 1 gram at a velocity of 1msec Conversions 1 calorie 4186 1kca 4186 kl 1kcal 1000 calories 6242009 Ei39 Energetic Efficiency The effective work performed after muscle contraction or efficiency is expressed as the percentage of total work Calculating Efficiency Gross Efficiency GE GE work accomplishedenergy expended X 100 Net Efficiency NE NE work accomplishedenergy expenditure resting energy expenditure x 100 E3 Energetic Efficiency Calculating Efficiency cont d Work Efficiency WE WE work accomplishedenergy expended energy expended in unloaded condition x 100 Delta Efficiency DE DE A work accomplished A energy expended x 100 Economy The oxygen uptake required to exercise at a certain intensity 6242009 E Measuring the Energy Content of Food Direct calorimetry is used to measure the energy content of food The food is combusted oxidized and the resulting heat is used as the measure of the energy content Usually 1 gram of food is placed in a bomb calorimeter with high oxygen pressure The resulting heat is the calorie content of the food Ki Measuring the Energy Content of Food Electrical igmllon j Thermometer Oxygen inlet 1 x r Water q hath Water bath mixer Bomb Pressurized oxygen Food Airspace 1 sample Insulating container Figure 3 Bomb Ci39ilu39imeiel E3 Measuring the Energy Content of Food Carbohydrate CHO Varies depending on the type of CHO 1 gram ofglucose 37 kcal 1 gram of glycogen 42 kcal Generally 1 gram of CHO 4 kcal Fat Lipids Also depends on the structure type of fat Generally 1 gram of Fat 9 kcal Protein PRO Depends on the type of PRO and nitrogen content Generally 1 gram of PRO 4 kcal E3 Measuring the Energy Content of Food Not all the energy from foods is actually available to humans ncomplete absorption and digestion Fiber content of food Atwater ractors 6242009 Ki Measuring the Energy Content of Food TIMI 3 Emmy CantM a Nuntum nd Ibo Availabi li of may In tho Indy Imrgy at mnhuninn mm available Camim nl per gram in U ml gt plr gram in la ml digestibility Anlmnl ions 111 555 In run 97 Plunlfood 117 539 I ISJlCleJ as Emmi load 7 77934101017 7 37 59317 vs 39 Magnum 5m 7 3M 55m quot150 mil w mallow 39 IOJ 190i union 9 mumm road 114 us my 1403 97 Ki Measuring Energy Expenditure Methods to measure EE in humans can range from direct complex to more indirect simple Examples Direct Calorimetry Indirect Calorimetry Closedcircuit spirometry Opencircuit spirometry Doubly labeled water Heart rate monitoring 6242009 Ki Measuring Energy Expenditure Direct Calorimetry rlgwu 32 Ki Measuring Energy Expenditure Indirect Calorimetry All biochemical reaction ultimately depend on the oxygen supply Indirect calorimetry refers to the amount of oxygen consumption and carbon dioxide production rather than the measurement of heat Measurement ofthe Respiratory Exchange Ratio RER RERVCOZVOZ 1L02 482 kcal Can range from N 47 kcal to 50 kcal depending on the proportion ofenergy coming from the breakdown of fat andCHO 6242009 Ki Measuring Energy Expenditure Closedcircuit and opencircuit spirometry Methods to measure oxygen consumption and carbon dioxide production Voiqu mm recorder 7 392 n Watc w 301 aDSDiDed bysodaiime gt CO pmdudrnn plus resvduai 0 Figure 33 r r cm H m Ki Measuring Energy Expenditure Closedcircuit and opencircuit spirometry cont d Respiration Chamber Figure 34 A eapun w umi 6242009 E Measuring Energy Expenditure Closedcircuit and opencircuit spirometry cont d BreathByBreath Systems 3 Measuring Energy Expenditure Indirect Calorimetry and Substrate Utilization Gas exchange measurements allow an estimation of not only energy expenditure but also the substrate mixture used The substrate used for energy therefore determines the total amount of oxygen required and carbon dioxide produced Respiratory Quotient RQ R0 vco2 v02 Requires steadystate measurements In theory RQ can range from 07 to 10 07 100 fat 10 100 CHO 6242009 6242009 E Measuring Energy Expenditure Indirect Calorimetry and Substrate Utilization cont d CHO cano6 02 co2 H20 cano6 602 eco2 6H20 RQ6C026021 Fat C16H3202 02 CO2 H20 C16H3202230216C0216H20 RQ 16C022302 0696 07 Limitations of using RQ Steady state conditions required Carbon dioxide produced must be entirely from the oxidation of substrates it Hcog lt gt H2C03 lt gt H20 co2 at Components of Energy Expenditure Energy is needed for different processes in the body Basal functions Digestion Absorption Metabolism Storage of food Energy for exercise physical activity Ei39 Components of Energy Expenditure Resting Metabolic Rate RMR The energy required for the maintenance of normal body functions and homeostasis in resting conditions Influenced by SNS activity thyroid hormones NaK pumps Basal Metabolic Rate BMR The lowest oxygen uptake in resting thermoneutral conditions Strict testing conditions 60 to 75 of daily EE in a relatively inactive person E2 Components of Energy Expenditure DietInduced Thermogenesis DIT Also termed Thermic Effect of Food TEF The increase in EE above RMR that occurs for several hours after the ingestion ofa meal The result of digestion absorption metabolizing and storage of food Approximately 10 ofthe daily EE Factors influencing magnitude of DIT Energy intake of food size of meal composition of meal metabolic fate of meal Storing Fat 3 of the energy of the ingested meal Storing CHO N7 Synthesis and breakdown of PRO 24 6242009 E Components of Energy Expenditure Thermic Effect of Exercise TEE Also termed Energy Effect of Activity VEEAV All energy expended above the RMR and DIT Most variable of all the components of daily EE Voluntary Component Exercise Involuntary Component shivering fidgeting postural control Values Up to 8000 kcalday for very active Much lowerfor sedentary 100 kcalday Averages about 30 of daily EE but can be upwards of 80 for very active individuals El Components of Energy Expenditure 8 MJ 20 MJ 6242009 Ki Energy Balance The difference between energy intake and energy expenditure Usually calculated for longer periods oftime Positive Intake gt Expenditure Negative Intake lt Expenditure En mm mm my E Energy Balance tau 3 Energy Imk In Variow Spam 7 MI 7 spam mu lmim39 kJIm mm 41 BL 6242009 E Energy Balance of Different Activities Table 33 Energy Costs of Different Activities Mlmim Ixnmph Eeymg i 39 ew i g n ocwnes ligi 0 i he iv ccerate armies Man2a own yes 15 quot streams actquot we Ki Energy Balance of Different Activities Table 34 intimated Energy Cost of Attivities in KilaJuulu per Minute Kllotuloriu per Minute 7lt3939 layman soka UM m m 90kg mum IJZIM 153M mum mm r Mi 39 LR 39rJ 2 iquot 6242009 6242009 W Lower Limits of EE i1 Some athletes in various sports exhibit very low levels of energy intake Gymnasts ballet dancers ice dancers Energy intake can be as low as 1000 to 2000 kcalday even though the level of activity is quite great Can be as low as 12 to 14 times the RMR Sedentary is 14 to 16 times RMR Why so low Desire for certain body composition profile Food consumption so low that DIT and RMR might be reduced Effects on nutrient status E Upper Limits of EE Various sports exhibit extremely high EE s and thus energy intake must be high as well in order to maintain energy balance Example Tour de France N 6000 kcalday EE 9000 kcalday Energy intake must be equally high to maintain performance but that is challenging Time for eating is limited Depressed hungerfeelings GI problems Other sports Norwegian CC skiers N 8600 kcalday Ultra Endurance runner N 10750 kcalday E Upper Limits of EE Energy Energy gmq expenalture infak 713cm l a gt E 5000 quot 30 g a quot a X Exercise lime days figure 39 f39 6242009
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