Medi214 Notes PDF

Week 1 Inquiry Question Notes Training, Nutrition, and the Athlete Athletes: Elite, Well-trained or collegiate, and Recreational Basic Sports Nutrition Guidelines ➔ Energy - Adequate to sup...

Week 1 Inquiry Question Notes Training, Nutrition, and the Athlete Athletes: Elite, Well-trained or collegiate, and Recreational Basic Sports Nutrition Guidelines ➔ Energy - Adequate to support training, recovery, and performance, and to maintain good health - Adjustments for weight loss ➔ Carbohydrates - 3 to 12 g/ kg of body weight - Varies largely by sport/Timing ➔ Proteins - 1.2 to 2.0 g/ kg of body weight - Assumes adequate energy intake ➔ Fats - 20 to 35% of total calories - Low fat ( transformed into different chemical forms. Can be used immediately or stored for later use - Humans very inefficient at energy transfer – only 25% in cycling, even less during swimming or running Bioenergetics The process of converting food into biologically useful forms of energy. Reaction types: Endergonic (storing) or Exergonic (releasing). High-energy phosphates from ATP. Measuring Energy Expended - Direct calorimetry - Indirect calorimetry: Oxygen consumption (VO2) and Carbon dioxide consumption (VCO2) - Resting metabolic rate (RMR) - Doubly labelled water (DLW): uses isotopes of hydrogen Energy Balance Energy in = energy out - Estimating Energy Intake: Self-reported food intake, Importance of accuracy, Common sources of errors. - Estimating Energy Expenditure: Total Energy Expenditure (TEE), Basal Metabolic Rate (BMR) Which RMR equation to use? Ten-Haaf equation, an equation developed in non-elite Dutch athletes and published in 2014, was the most accurate equation for general use in athletes: - Males: BMR (kCal/day) = (11.936 × weight in kg) + (587.728 × height in m) - (8.129 × age in years) + 220.306 - Females: BMR (kCal/day) = (11.936 × weight in kg) + (587.728 × height in m) - (8.129 × age in years) + 29.279 Estimating the energy cost of running - Running continuously can be estimated with reasonable accuracy on a hard flat surface. - Energy Expenditure in Running = 1 kCal/kg body mass/km run OR 3.6-4.0 kJ/kg/km - Running speed not included in the equation - EE is uniform across running pace if the same total distance is covered. - For uphill and downhill running, there may be variance of up to 30% above or below this figure. - Loop course that has the same amount of elevation gain and loss will likely see the overall expenditure being the same as a flat course. - Running on uneven or softer surfaces (e.g. trail running) will likely result in a higher caloric expenditure for the same distance. Approx 10-15% greater energy cost (i.e. 1.1 to 1.15 kCal/kg/km). Estimating the energy cost of cycling - Power = a measure of energy expenditure over time: 1 Watt = 3.6 kJ per hour or 0.06 kJ per minute Or power (wattsW) = work done joules (J) / Time (sec) - So if a cyclist rides at 200W for 2 hours, that's: 200W x 3.6 kJ/hr x 2 hours = 1,440 kJ or 344 kCal - Power metres only measure the energy expenditure that is transferred through the pedals of a bike (gross mechanical efficiency). - The % of energy that goes through the pedals does not vary much at different exercise intensities or from one cyclist to another, whether recreational or professional and is approximately 25% for cycling. - Thus, Total energy expended = 1,440 kJ ÷ 0.25 = 5760 or 1371kCal. Estimating the energy cost of swimming Difficult to estimate (stroke efficiency, body fat, stroke, open water). EG for freestyle swimming in a pool (not definitive): - Energy expenditure (in kJ per meter swum) = 0.67 x Speed (m/s)1.614 - For non-elite swimmers (male or female): Energy expenditure (kJ/m) = Energy expenditure (calculated above) x (0.668 x speed (m/s)) + 0.889 - Additional correction for females: Energy expenditure (kJ/m) = Energy expenditure (calculated above for males) x 0.76 Estimating energy expenditure in team & racquet sports - Non-continuous PA difficult to estimate the expected energy cost of. - At the professional level, the use of GPS data to estimate 'metabolic power' used for estimation. This concept uses  acceleration and deceleration (underestimates). Calculating energy using METs Metabolic equivalents are defined as caloric consumption (by means of breathing) of an active individual compared with their resting basal metabolic rate (oxygen consumed during activity compared to oxygen consumed at rest). Most individuals at rest utilise ~3.5mL of oxygen per kg of body weight per minute which equates to 1 kcal/kg/hr. - 1 MET roughly estimated to be 1 RMR - Recent studies show that true resting MET values are much lower than 3.5mL/kg/min - Influenced by age, gender, body fat, muscle mass, and illness significantly affect this value. If something requires 2 METS, then it requires twice the resting metabolism. When performing exercise, MET values are assigned to various forms of physical activity to determine how many calories are expended during that activity. Compendium of Physical Activities: Created to provide a standardised way of measuring and classifying physical activities to assess energy expenditure. Provides specific Activities and their MET values. Summary Week 2 Inquiry Question Notes Energy Systems and Exercise There are few situations encountered by the human body that utilise ATP at a faster rate than exercise, so sport and exercise are excellent models to study the energy systems that lead to the restoration of ATP. Inadequate food intake can lead to a lack of fuel and substrates that the body needs to restore ATP, and this can affect speed, distance, power, strength, or stamina. Describe the rephosphoryla- Overview of Energy Systems tion of ATP and the general Hydrolysis of ATP from ADP: ATP >>ATPase>> ADP + Pi + energy. Most energy comes from the release of third phosphate. characteristics of the creatine phosphate, anaerobic ADP + Pi + Energy >> ATP glycolysis, and oxidative - During aerobic conditions, heart cells only have approx. 8 secs of ATP (ie no oxygen). Therefore ATP cannot be stored phosphorylation energy and needs to be resynthesised. systems. - Contraction of skeletal muscles: concentric, isocentric and eccentric. Must continue to supply ATP in order for muscle contraction to continue. ATP >>myosin ATPase>> ADP = release of energy. Energy systems always operating.Resynthesis of ATP: 1. Creatine phosphate 2. Anaerobic glycolysis 3. Oxidative phosphorylation Speed of action Amount of ATP replenished Duration of action During a maximum effort exercise CPr Very Fast Very small Very short test over 30s there is an inverse contribution of the PCr/Glycolysis AG Fast Small Short contribution with that of oxidative metabolism. The 15-30s time period is dominated by oxidative OP Very slow (more membranes to pass through) Large Very long phosphorylation. ATP turnover declines over time. Describe the specific The Creatine Phosphate Energy System characteristics of the creatine - High-energy phosphate compound similar to ATP phosphate energy system, - Stored in muscle and other tissues and explain how it is used to - May also be referred to as phosphocreatine, PC, PCr, and CP replenish ATP during - Serves as a readily accessible reservoir of energy (in muscles near contractile muscles, limited on creatine sitting in fibre) exercise. - Creatine phosphate >> creatine kinase >> ATP + creatine - High concentration of creatine in fast twitch fibres (larger can ack in more creatine) - Creatine in blood is a balance between consumption of food, creatine used from blood, creatine broken down and excreted and how much creatine we are producing ourselves. - Dietary creatine. Beef 0.45g per 100g. Easy to uptake (supplements) and absorb. - Creatine can be metabolised into creatinine which is then excreted via kidneys. - Group A supplement: evidence to support that creatine supports physiological adaptation and performance - Fatigue associated with CrP depletion - 1 ATP per CrP molecule - Not entirely anaerobic as it involves the mitochondria during ‘The Creatine Shuttle’ Utilisation of ATP and Creatine Phosphate during Short, High-Intensity Exercise: ATP relatively undisturbed (good). Creatine begins in high conc. before dropping as CPr is delivering phosphate to ADP for resynthesis to ATP. Describe the specific The Anaerobic Glycolysis System characteristics of the CHO >> 2ATP + lactic acid >> Lactate + H+ anaerobic glycolysis energy Energy in the form of two ATP is needed to allow the reaction to proceed (glycolysis produces 4 ATP but 2 are used in process = system, and explain how it is net 2 ATP). Sufficient energy is released in subsequent chemical reactions to re-form four ATP. When the process commences used to replenish ATP during from stored glycogen, it is called glycogenolysis. exercise. - Anaerobic: 1- to 2-minute duration (no O2) - Rate-limiting enzyme: phosphofructokinase (PFK) - Fatigue associated with decreased pH (metabolic acidosis) - 12 chemical compounds, 11 enzymes - 18 chemical steps/reactions; 6 are repeated The Fate of Lactate Lactate shuttling occurs in many physiological and pathological conditions, where in lactate is exported by one cell type and imported by another cell type. The well-known Cori cycle involves lactate shuttling between skeletal muscle and the liver. Therefore, due to both release and uptake rates impacting the actual concentration of La, it is non-precise in terms of its relationship to energy systems per se. Picture: A: 60% and B: 110% of peak aerobic power result in the excess production of H+ ions. However, released from the muscle is an exponential conc of H+ compared to lactate (especially for 5 min). Peak aerobic power = peak vo2 Describe the specific The Oxidative Phosphorylation System characteristics of the CHO/FAT/PROTEIN >> Krebs cycle and electron transport chain >> ATP oxidative phosphorylation 1. Glucose follows the steps of glycolysis, except that rather than being converted to lactate, pyruvate is transported into a (aerobic) energy system, and mitochondria for aerobic metabolism. explain how it is used to 2. Pyruvate goes through the Krebs cycle, a series of chemical reactions that oxidise, or remove, the electrons from the replenish ATP during intermediate compounds in the process. exercise. 3. The electrons are transported to the electron transport chain where they participate in a series of reactions that release sufficient energy to phosphorylate ADP to ATP. 4. Oxygen is the final electron acceptor and forms water. - Aerobic/slow but potentially limitless duration - Fatigue associated with fuel depletion (for example, muscle glycogen) - 124 chemical steps/reactions, 30 compounds, 27 enzymes - Rate-limiting enzymes: phosphofructokinase - 30 ATP via glucose, 31 ATP via glycogen (in skeletal muscle) Explain the process of Fuel Utilisation aerobic metabolism of Oxidation of Carbohydrates, Proteins, and Fats: carbohydrates, fats, and - Carbohydrates are metabolised as glucose via glycolysis to pyruvate and produce 30 ATP through oxidative proteins (amino acids), the phosphorylation in skeletal muscle. concept of measuring fuel - Fats (least effect >O2) are metabolised in a variety of ways; the fatty acid palmitate is shown. The process of b-oxidation utilisation with the respiratory converts two-carbon portions of palmitate to acetyl CoA where it enters oxidative phosphorylation, eventually producing exchange ratio, and describe 113 ATP. the factors that influence fuel - Metabolism of alanine and isoleucine are two examples of protein metabolism. After removing the nitrogen group, utilisation. alanine can enter the metabolic pathway as pyruvate, producing 10.5 ATP, whereas isoleucine enters as acetyl CoA, resulting in the production of 34 ATP. Triglyceride and fat oxidation  The ‘Normal’ responses when taking 8481 steps/day the day before was a high rate of fat oxidation and a low level of plasma triglyceride concentration during the postprandial test. On the contrary, when taking either Low (2675 steps/day) or Limited (4759 steps/day) exercise, the postprandial triglyceride was significantly elevated (A) and fat oxidation significantly reduced (B) compared to Normal (P < 0.05). ∗Low and Limited are significantly different from Normal (P < 0.05). Critical Power Profile – insight to metabolism RER 1 = 1 CO2 mol for every O2 consumed Hyperbolic relationship with rapid decline occurring. Functional Threshold Power: Ability to sustain power constantly providing aerobic based fuel source. Oxygen Consumption Describe the response of Oxygen consumption (VO2), if its an aerobic based activity, is an indirect measure of energy expenditure and heat production. oxygen consumption to - Maximal Energy Consumption (VO2max): linear relationship. After time there would be a theoretical plateau and athletes steady state and submaximal will reach voluntary exhaustion (can't go any further based on aerobic system). exercise, and explain the - Submaximal exercise: Reaches theoretical oxygen consumption that meets the aerobic metabolism. Ie delivers enough concept of maximal oxygen O2 to supply the mitochondria in order to resynthesise ATP. Post exercise: excess oxygen consumption and blood flow still consumption (V̇ O2max). increased. Oxygen slow component VO2 slow component: putative mediators - 80%: contracting muscles. Depending on intensity, metabolic requirement of fatiguing fibres (ie ion pumping, metabolite effects; H+ accumulation). Recruitment of lower efficiency motor units (type 2b/d/x - fast twitch fibres - low oxidative fibres) leading to drop in efficiency and rise is O2 consumption. - 20%: rest of body. Ve work, O2 cost, cardiac work Explain the concept of the ‘oxygen slow component’ as it relates to the energy systems and therefore the maximal work capacity according to duration of time. Oxygen slow component – Nutrition - CHO depleted versus CHO restored conditions (do they have enough CHO to replenish glycogen)  - Type I fibres, which are low in glycogen, are unable to continue the same contribution to the work - Type II fibres are recruited at an earlier stage, and these fibres are less efficient (O2) in the resynthesis of ATP. - Evident higher oxygen consumption that is also drifting by minutes 15-20. Beetroot juice: - Dietary nitrate is classed in Group A (performance enhancing) - Increased nitrate contributes to nitric oxide synthase production (NOS) which promotes vasodilation of blood vessels - L-arginine also stimulates NOS activity in the same way - Both pathways promote blood flow especially at the commencement of muscle contractions - This repeated muscle contraction study (left) shows a reduction in the slow component of the oxygen consumption and Severe bout = close to VO2 max. less disturbance of PCr in the muscle, following the ingestion of beetroot juice. Under constant work rate o2 uptake - Time to exhaustion is also increased. will exponentially rise. Slow - The increased, rapid blood flow is thought to provide the contracting skeletal muscle with a more immediate oxygen becomes more exacerbated as time goes on. supply, and therefore Type I efficiency (and less requirement to recruit Type II fibres). Bicarbonate - Dietary sodium bicarbonate loading is classed in Group A (performance enhancing) - More time was spent in the rapid component and then there was a blunting of the slow component - Reasoning was levelled at the changed metabolic factors (H+), however, these are not the full explanation. Summary - Provision of energy is dependent on multiple factors, no less so the intensity and duration of the exercise stimulus. - Even short duration exercise will require aerobic based metabolism, especially if there is a multiple bout effect - The intensity of exercise (relative to the peak aerobic power) influences the mix of substrates used to fulfil the ATP resynthesis rate, according to muscle fibre type. - Oxygen consumption is observed to undergo a ‘slow component’ best described as a rise in the metabolic rate, despite the external work remaining relatively constant - The presence and extent of the ‘slow component’ is high influenced by the training status of the individual, and most likely underpinned by the muscle fibre type contribution to the exercise. Week 3/4 Inquiry Question Notes Classify CHO according to Carbohydrates in food their chemical composition. - Monosaccharides > Disaccharides > Polysaccharides - There is no single way to classify carbohydrates (ie sugars vs starches, simple vs complex, etc)  Characteristics of Monosaccharides 6C, 12H, 6O Chemical Sweetness (100 Glycemic index name = Sweetness of (based on 100) table sugar) ie blood sugar Glucose 75 100 In the body, found circulating in the blood and stored as glycogen. In food, generally found as part of disaccharides and polysaccharides (starches). When added to food, glucose is referred to as dextrose. Fructose 170 19 In the body, found temporarily in the liver before being converted to glucose. In food, found naturally in fruits and vegetables and added to processed foods, often as high-fructose corn syrup. Galactose 30 Unknown Found in food only as part of lactose. Characteristics of Disaccharides Chemical Monosaccharide Sweetness (100 Glycemic name composition = Sweetness of index (based table sugar) on 100) ie blood sugar Sucrose Glucose + fructose 100 68 Found in fruits, vegetables, honey, and maple syrup; sugar beets and sugar cane are processed into white and brown sugar. Lactose Glucose + galactose 15 46 Most adults lose their ability to digest lactose (milk sugar). Maltose Glucose + Glucose 40 105 Minor disaccharide in most diets Polysaccharides Starch (Amylopectin − Amylose), glycogen, fibre (eg cellulose). Describe the digestion and Digestion, Absorption, and Transportation of Carbohydrates absorption of carbohydrates. - Digestion: Breaking down. Absorption: Actual absorption into blood, etc - For CHO the majority of digestion takes place in the small intestine as well as the majority of absorption. - Villi increase SA to maximise absorption Explain the metabolism of Metabolism of Glucose in the Body glucose. Involves many metabolic pathways, which include: - The regulation of blood glucose concentration - The immediate use of glucose for energy (ie competition) - The storage of glucose as glycogen - The use of excess glucose for fatty acid synthesis - The production of glucose from lactate, amino acids, or glycerol Metabolism of Carbohydrate Once in cell glucose can be used immediately or stored for later use depending on requirements. How glucose is metabolised depends on several factors: - Cell type i.e. Red blood cells vs heart cells or slow twitch muscle fibre - Enzymatic ability of cell - Energy state i.e. glycogen status - Hormonal status - Training hx - Intensity of exercise i.e. aerobically or anaerobically Describe how muscle Use of Muscle Glycogen During Exercise glycogen and blood glucose The effect of different exercise intensities (lines on the same graph) and different baseline muscle glycogen (individual are used to fuel exercise. graphs) on muscle glycogen utilisation - Muscle glycogen use increases with the intensity of exercise - Fatigue at high intensity exercise levels (100 & 130% VO2max) aren’t associated with low muscle glycogen stores - At 70% VO2max the point of fatigue is associated with low muscle glycogen stores. - In Figure c., when starting muscle glycogen stores are highest – time to exhaustion @ 70% VO2max is extended in comparison to Figures a. and b., where starting muscle glycogen stores are lower. - Of note, an important adaptation to endurance training is the increased ability to store carbohydrate (glycogen) in the muscle. - Note time to fatigue only estimated in 70% VO2max Muscle Glycogen Content  - Muscle glycogen content varies depending on both diet and training status - A trained athlete has a greater capacity for glycogen storage - CHO further enhanced by a high carbohydrate intake - Dictates CHO fuelling strategies. i.e. more aggressive CHO intake leading into enduro event in well trained athletes - Starting glycogen conc depends principally on training status + pre-exercise dietary CHO intake Carbohydrate Oxidation Rates Multiple factors influence CHO oxidation rates. Two main ones: 1. Total energy expenditure (TEE) − Exercise intensity and body mass 2. Proportion of energy from CHO - Acute CHO availability i.e. fed vs fasted - Habitual CHO intake i.e. high vs low CHO - Training status - Exercise intensity Can be determined in the lab looking at RER CO2 output vs O2 intake. High carbohydrate availability - Acute High carbohydrate availability in an acute exercise setting can be achieved by: - Deliberately elevating pre-exercise muscle glycogen stores - Consuming a carbohydrate rich pre exercise meal - Consuming carbohydrate during exercise Research consistently shows that exercise with high CHO availability improves acute exercise performance compared to exercising in a state of lower carbohydrate availability (i.e. fasted). High Carbohydrate Availability - Chronic Study Achten et al (2004): Runners undertook an 11-day training block, whilst consuming either 5.4 or 8.5 g/kg/day CHO. On days 1, 5, 8 and 11 runners completed a laboratory performance test, with easy training on days 2,3 and 4, and hard training days on days 6, 7, 9, and 10. Results: At baseline no difference, on day 5 no difference between which is expected due to easy days before. When hard training kicked in, the high carb group performed much better. Low CHO availability - LCHF Diets for Athletes (low carb high fat diets) Upregulation of fat oxidation + shift point of fatmax to higher % VO2max. Generally endurance focused with several theories on benefits: - Muscle glycogen limited – fat is just about unlimited - Less CHO during activity required - Fat as a substrate produces more energy/gram > weight efficient fuel source - Can train at lower CHO intake without training compromise and could be beneficial for reducing body weight/fat - Depending what we eat can shift what is used for energy Carbohydrate availability - Glycogen Threshold Hypothesis Metabolic adaptations occur within skeletal muscle in highly trained athletes at submaximal work rates. Ways we can have  metabolic transformations to improve performance: - increased capillarisation - mitochondrial density - mitochondrial number - enhanced activity of mitochondrial enzymes such as 3-hydroxyacyl-CoA dehydrogenase (HAD) and citrate synthase (CS) - enhanced lactate oxidation - increased concentration of transport proteins - glycogen concentration - ability to metabolise fat as a substrate Training with low carbohydrate availability enhances the metabolic adaptation to exercise. Research suggests that it is the Detail and explain CHO post-exercise glycogen concentration that influences the level of adaptation that occurs, ‘glycogen threshold hypothesis’. recommendations for To maximise training adaptations, the post-exercise muscle glycogen concentration should be below a "threshold" value, athletes, including specific proposed to be ~ 300mmol/dry wt. Muscle. guidelines for intake before, during, and after exercise. Low CHO Availability Strategies Instead of following a LCHF diet other nutritional strategies could be employed: Training fasted, No CHO during training, Describe how CHO Delayed rescue (no CHO post training), Training twice daily second session no CHO or Sleep low. periodisation could be used to optimise exercise Carbohydrates and gut training performance Training with high carbohydrate availability ensures athletes are prepared for competition. Particularly important if significant carbohydrate intake is required during their competitive event. Gut training crucial for several reasons: Determine the daily CHO - To ensure the athlete is familiar with the sports foods and drinks they will consume: taste, storage/carrying items, needs of an athlete, and open the packaging, consume them safely and confidently select carbohydrate- - To ensure the athlete is familiar with the timing and quantities containing foods to meet the - To ensure the athlete's gastrointestinal tolerance of the planned food and fluids is sufficient to ensure adequate recommended intake. digestion and absorption (and minimise GI symptoms) during competition. Gut training – Costa et al (2017) Study - Endurance runners completed a "gut challenge", 2 hours treadmill running at 60% VO2max whilst consuming 90g/hr of carbohydrate (glucose/fructose mix). Immediately followed by a 1-hour distance trial, where participants ran as far as possible in 1 hour. - Gut training consisted of 2 weeks of training 5 days/wk, 1 hour run, randomly assigned to consume 90g CHO from either gels or food, or a placebo gel. - The gut challenge and performance test was then repeated following gut training. Total and upper GI symptoms were significantly reduced in the CHO groups, with no change in the placebo group. Gut Training Implementation Currently no consensus or published guidelines. Possible strategies: Undertake training sessions with the target amount of carbohydrate at least 1-2 times a week. If rapid gut training is required, more frequent sessions may be required.  ➔ Gut Challenge - If oxidation rate testing is available, a gut challenge can be undertaken. - At race pace, feed 90g/hr, measuring oxidation rate every 30min for 2-3 hours (endurance athletes only). If CHO oxidation is poor (e.g. >during 12g/kg per day is only for very elite athletes (e.g. endurance runner). Carbohydrate Recommendations - Post Activity ➔ Within the first hour: Carbohydrate-rich meal with at least 1g carb/kg body weight ➔ Less than 8 hrs until next session: - 1-1.2g carb/kg BW, optimal early on i.e. within the first 4 hours post activity - 6-12g carb/kg BW daily - It is an aggressive form of refuelling. Immediate post exercise period – rates of glycogen synthesis are greatest. Understanding the goal of training Crucial to understand daily demands of exercise − Influences energy and CHO intake (and other nutrition). Dynamic training plans and goals - therefore variable CHO: Purpose of session, Performance outcome, General conditioning, Skills based, Resistance exercise, Fat oxidation. Translating Daily Carbohydrate Recommendations to Food Choices >> Low fodmap diets for people with diseases. CHO Periodisation in Practice Manipulating CHO to achieve a purpose: Training with high CHO, Matching training load, Gut training, Supporting bone – reduce bone mineral density over time, Training with low CHO (Note: not energy intake). USOC Plate Model USOC Sports Dietitians + University of Colorado designed a series of plate models which illustrate how an athlete could alter their food intake in response to daily training and the athlete’s physique goals. - CHO containing foods are the foods that create the change in dietary energy intake on heavier training days - Note that a limitation with this model is that a change in the size of the plate to accommodate different training days is not included Summary Week 5 - protein Inquiry Question Notes Describe amino acids and Structure and Function of Protein how the structure of a Basic Structure of an Amino Acid: Amino group, carboxyl group, side chain protein affects its functions. Don't need to know specifics of all 20 AAs, need to know classification: Dispensable: Made in body / Indispensable: Intake / Conditionally Indispensable: no longer able to generate Protein Structure - Primary structure: determined by amino acids (chemical bonds) - Secondary structure: Determined by weak electrical attraction within polypeptides (H bonding > a-helix or b sheets). Provides strength and rigidity - Tertiary structure: Polypeptide chain twists and folds; side groups attracted = intricate shape (e.g. disulphide bridges in insulin) - Quaternary structure: Interactions between multiple polypeptides (e.g. haemoglobin) Protein category Functions Component of enzymes Enzymes are specialised proteins that speed up (catalyse) chemical reactions in cells Component of hormones and Hormones, many of which are protein based, regulate metabolic processes; signalling proteins (cytokines) are signalling proteins known as growth factors and can bind to the surface of a cell and influence its cellular processes; some amino acids stimulate signalling proteins necessary for skeletal muscle protein synthesis (MPS) Structural proteins Component of muscle, connective tissue, skin, hair, and nails Transport proteins Part of molecules that allow compounds to be transported, such as oxygen, carbon dioxide, iron, and fats Immune system proteins Fundamental component of the immune system  Acid-base regulator AAs have both acid and basic groups; help the body to achieve acid-base balance/optimal pH Fluid regulator Proteins, especially those found in the blood, help to maintain fluid balance Source of energy Under normal conditions, a minor energy source; under temporary stressful conditions, a small but important source of energy; under severe or prolonged stress, such as starvation, a major source of energy but to the detriment of health Describe the digestion, absorption, and Digestion, Absorption, and Transportation of Protein transportation of amino Commercially available protein supplements: acids. - May be ‘predigested’ or hydrolysed: Dipeptide or tripeptide form - Could control “fast” or “slow” release: slow may be in long polypeptide form and available in blood for several hours Amino Acid Pool and Turnover - Free AAs circulating in blood or fluid near cells - Some of the amino acids have recently been absorbed from the gastrointestinal tract - Most come from the breakdown of body tissues, including skeletal muscle tissue - Average of 150 g of amino acids; ~80 g is glutamine - More dispensable than indispensable AAs - Always in flux because of protein turnover Explain protein metabolism and the processes Metabolism of Proteins and Amino Acids associated with skeletal Deamination: Removal of amino group. A-ketobutyrate can be oxidised for energy. muscle protein synthesis Skeletal muscle turnover: and breakdown. - Can entre and exit via blood - de novo synthesis: create AA on its own. AA for ATP: important 6 at the top which can be converted to glucose Nitrogen Balance and Net Protein Balance: - Nitrogen balance: Difference between total nitrogen intake (protein) and total nitrogen losses (via urine and faeces) - Net protein balance: Difference between MPS and MPB. Achieved if MPS = MPB - Positive nitrogen balance: Growth period, for example, pregnancy. Hypertrophy in gym. Consume > loose - Negative nitrogen balance: losing more nitrogen then consuming Muscle anatomy and protein types - Sarcoplasmic proteins: in between myofibril where muscle glycogen is stored. - Mitochondrial proteins - Myofibrillar proteins Determine daily protein recommendations for Protein Recommendation Considerations athletes and the amount, Modern sports nutrition guidelines now consider several factors when recommending protein intake for athletes: quality, distribution, and - The amount of protein per day or at any one eating occasion timing of protein intake - The distribution of protein intake across meals and snacks over the day before, during, and after exercise. - The food source/type of protein consumed - The influence of the type, volume and timing of exercise in relation to protein needs - The influence and interaction of other nutrients on protein metabolism - The influence of energy balance and/or energy availability - The body composition and performance goals of the athlete Protein dose in a single eating occasion Young participants performed leg extension exercises, with a one-off dose of egg albumin protein post exercise. Protein dose varied between 0, 10, 20 and 40g protein per serve. Protein synthesis in the 4 hours following exercise was maximally stimulated at 20g, with no further increase after doubling protein intake. FSR = Fractional Synthesis Rate Protein Dose and the Leucine Trigger Leucine has a unique signalling role in triggering the increase in muscle protein synthesis. - An exact leucine "threshold" for muscle protein synthesis has not been quantified from research - Appears to be approx. 2-3g but many variables Protein Intake for MPS and Age - Older adults (71 ± 1 yrs): The plateau in muscle protein synthesis with increasing protein intake occurred at around 0.40 ± 0.19 g/kg in older men. - Younger adults (22 ± 4 yrs): The plateau in muscle protein synthesis with increasing protein intake occurred at around 0.24 ± 0.06 g/kg in younger men. Protein Timing and Distribution - Areta et al study compared three different patterns of ingestion of 80 g of protein during 12 h recovery after resistance exercise and the associated anabolic response in human skeletal muscle. - Protein was ingested in 10, 20 or 40 g feedings using a pulsed, intermediate or bolus ingestion regimen respectively - Results indicate that repeated ingestion of 20 g of protein was superior for stimulating muscle protein synthesis during the 12 h experimental period. - This study shows that the distribution of protein intake is an important variable to promote attainment and maintenance of peak muscle mass. Protein Quality Based on amounts and types of amino acids and the extent to which they are absorbed. Digestibility scores: DIAAS and PDCAAS. - Complete proteins: Contains all amino acids found in food - Incomplete proteins: Different ratio - Complementary proteins: 2 incomplete proteins consumed at same time Milk/Whey vs Other Plant Increased research focuses on the comparison of milk or whey compared to plant protein sources in recent years. Overall, the evidence suggests that in sufficient quantities (~30g of protein in a single serve), the protein synthetic response from plant proteins does not differ from animal proteins. Protein supplements vs whole foods Pros of wholefoods: - Whole foods contribute to overall diet quality, ensuring adequate intakes of carbohydrate, desirable fatty acids, fibre and micronutrients. - Additional nutrients and components within whole foods that contribute positively to muscle protein turnover. Cons of Whole foods:  - Lack of nutrients in supplements may increase their rate of digestion and absorption, achieving a greater peak leucine concentration and reducing the volume of food or beverage that needs to be consumed to achieve the desired protein intake. - Supplements can provide a targeted fraction of the whole food proteins, such as the whey fraction of dairy protein. - Supplements are convenient. Protein Dose and the Leucine Trigger - The protein dose required for any given eating occasion is designed to achieve a certain level of plasma leucine concentration - Food-First Approach to Enhance the Regulation of Postexercise Skeletal Muscle Protein Synthesis and Remodelling. Wholefood: takes less protein to enhance trigger - The threshold level for triggering protein synthesis appears to be modified by several factors − Food matrix vs isolated protein Protein Supplements - Protein supplements are heavily advertised to strength/power athletes. - Useful for other athletes as well In the presence of resistance training and adequate calories, proteins from either food or supplement sources can contribute to increasing skeletal muscle size and strength and aid in recovery. - Protein supplements are neither more nor less effective than food proteins for skeletal muscle growth. Protein Timing and Distribution – Pre-sleep Protein Feeding Overnight is the longest fasting period during the 24 hours of the day/night cycle. Therefore, likely to be in a prolonged period of negative protein balance. Research confirms protein ingested prior to bed stimulates MPS. - Study: N=44, randomly assigned to a progressive, 12-wk resistance exercise training program. One group consumed a protein supplement containing 27.5 g of protein, 15 g of carbohydrate, and 0.1 g of fat every night before sleep. The other group received a noncaloric placebo. Strength was assessed regularly by 1-repetition maximum strength testing - Result: If training in the evening, consuming 2 meals with adequate protein likely results in more favourable adaptations than a single meal. - Casein protein powders before bed suggested to facilitate a slow, steady release of amino acids throughout the night, although research still lacking Protein distribution in athletes The protein distribution of athletes across the day has been studied in different contexts. ~0.35-0.5g/kg or 20-40g is optimal for most athletes and in most scenarios. Approximate range of recommended protein dose highlighted in green Protein for endurance athletes The effect of protein dose and distribution has been much less studied in endurance athletes. In 2020 the first dose-response study of protein ingestion and protein synthetic responses was published. - In this study, 48 healthy, young, endurance-trained men completed 90 min cycling at 60% VO2max. - Afterwards, they were given 45 g carbohydrates along with either 0g, 15g, 30g, or 45g milk protein. - Myofibrillar and mitochondrial fractional synthetic rate (i.e. protein synthesis) was measured over the following 6 hours. - Myofibrillar Protein Synthesis: A main effect of protein dose was observed, and when comparing pairs of protein doses, 30g and 45g were equally effective, but 45g was more effective than 15g. - Mitochondrial Protein Synthesis: There was no effect of protein dose on the amount of mitochondrial protein synthesis in the 6 hours following exercise. - Myofibrillar Protein Synthesis (per kg BM): When expressed per kg body mass, maximal myofibrillar protein synthesis was achieved at a dose of 0.49g/kg post-exercise. Interestingly, this figure is somewhat greater than is usually observed for resistance training in a similar age group.  There are multiple proposed mechanisms by which protein could be useful for endurance athletes. These include: - Oxidation of amino acids to be used for hepatic gluconeogenesis and (or) deamination - As a fuel source by skeletal muscle mitochondria - Increases in mitochondrial protein synthesis to enhance substrate metabolism and utilisation - Promotion of myofibrillar remodelling to maintain muscle protein quality and function by removing old or damaged proteins - Stimulation of net myofibrillar protein synthesis to enable greater muscle force/power output; - Promotion of glycogen resynthesis when co-ingested with carbohydrate (CHO). Describe the effects of low protein and energy intakes Effect of Energy Intake on Protein Intake on training, recovery, Recommendations to Athletes who are “Dieting” (ie making weight): performance, and health. - Daily energy deficit should be moderate (500 kcal). - Resistance exercise must be performed. - Daily protein intake should be at least 1.8 g/kg. - Post-exercise protein consumption should be 0.25 to 0.3 g/kg or perhaps higher (0.4) - Meals or substantial snacks, each containing about an equal amount of protein, should be distributed evenly throughout the day Translate protein recommendations into daily Translating Protein Intake Recommendations to Practical, Daily Food Choices food intake, and assess an athlete’s dietary protein intake. Describe current protein intake guidelines for athletes and sedentary populations, and current and emerging literature to support or disputes these guidelines. Identify additional factors that interact with muscle protein metabolism, including energy balance, dietary protein source, quantity and timing, the presence of other macro and micro nutrients and age, Summary Week 6 - Fats Inquiry Question Notes Broad:  - Fat provides an essential supply of energy for the high demands of exercise training and recovery. - The current guidelines recommend that 20-35% of total energy (kilojoules/kilocalories) consumed comes from dietary fat, but the amount required will vary between individuals. - Consumption of mono and poly-unsaturated fats as a preference to over consumption of saturated fats - CHO are agreed to play the most important role in the supply of replenished energy provision. - ‘Fat adaptation’ (so called metabolic advantage), although has some evidence for adjusting fat specific enzyme activity, has limited evidence as performance enhancer, and that even includes when used in a periodised fashion (with glycogen re-loading) (see later slides for context). - Absorption of certain vitamins (specifically vitamins A,D, E & K), protecting vital organs and aiding hormone production. Classify fats according to - Polyunsaturated fatty acids include both the main groups of omega-6 and omega-3 fatty acids. Inclusion of these in their chemical composition, the diet also influence the membrane lipid layers of body tissues, where for example, this may also result in and distinguish between modification to inflammatory responses. saturated and unsaturated, monounsaturated and Fatty Acids, Sterols, and Phospholipids polyunsaturated, cis and Fatty acids: Saturated (no db), monounsaturated (1 db), polyunsaturated (2 db). Trans fatty acid: H sits on either side. trans, and omega-3, -6, and -9 fatty acids. Benefits of Omega-3 Fatty Acids: Name Characteristic Source a-linolenic acid (ALA) Essential fatty acid that is widely distributed in food; can be used to form Abundant in flaxseed and rapeseed oils and longer fatty Acids green leafy vegetables; also found in soybean, canola, and linseed oils Eicosapentaenoic acid Eicosanoids made from EPA have anti inflammatory effects and inhibit Marine (“oily”) fish such as salmon, herring, (EPA) the formation of eicosanoids made from arachidonic acid, which have mackerel, and sardines; supplements pro-inflammatory effects Docosahexaenoic acid Major component of membrane phospholipids; eicosanoids made from Marine (“oily”) fish such as salmon, herring, (DHA) DHA have anti-inflammatory, pro-resolving effects and inhibit the mackerel, and sardines; supplements formation of eicosanoids made from arachidonic acid, which have proinflammatory effects Describe the digestion, absorption, and Digestion, Absorption, and Transportation of Fats transportation of fat. Explain the metabolism of fat, including mobilisation, Why might an athlete limit their fat intake 2 to 4 hours before a competition, game, or heavy training session? transportation, uptake, Fat surges up and can last for upwards of 8 hours. activation, translocation, and oxidation, as well as ketosis Storage and Metabolism of Fats and the effect it may have on Lipoprotein lipase activity is stimulated by insulin. Fat storage in muscle occurs primarily in muscle that is highly aerobic training. Advantages: Very “energy dense” nutrient, 9 kcal/g (twice that of CHO or protein) and Anhydrous. - Esterification: Formation of a triglyceride. Occurs after fatty acids are taken up by adipocytes - Beta-oxidation: Conversion of fatty acids to acetyl CoA - Lipolysis: Breakdown of a triglyceride to fatty acids and glycerol. Inhibited by insulin - Ketosis: Catabolism of acetyl CoA Mitochondrial Transfer of Fatty Acyl-CoA: Under aerobic based process. FAs must enter inner mitochondrial membrane Ketosis Normal metabolic pathway, sometimes referred to as an “overflow” pathway. Ketones: - Produced by liver as glycogen levels fall - Supply 2 to 6 percent of the body’s total energy needs after an overnight fast - Increased production when fatty acid oxidation is accelerated: Low CHO intake or Impaired CHO metabolism Fats as a Source of Energy during Exercise Describe how the body uses fat to fuel exercise and how manipulating the amount of fat in the diet affects fat oxidation. Fat Recommendations for Athletes - General guidelines: Approximately 1.0 g/kg. 20 to 35 percent of total caloric intake - Total fat amount depends on Total energy + Total carbohydrate and protein - Endurance athletes may need up to 2.0 g/kg/d Effects of Inadequate Fat Intake Usually accompanied by energy restriction accompanies. Can negatively affect training, performance, and health: - Inadequate replenishment of intramuscular fat stores - Inability to manufacture sex-related hormones - Alterations in the ratio of high-and low-density lipoproteins (HDL:LDL) - Inadequate fat-soluble vitamin intakes ‘Anorexia athletica’ State fat recommendations for athletes, and calculate Translating Daily Fat Recommendations to Food Choices the amount of fat needed Amounts and Types of Fats in Food: Total fat, Saturated fat, Trans fat, Cholesterol, Amount of fatty acids daily. Ways to Modify the Typical American Diet Typically high red meat, processed foods, refined grains, high-fat dairy products - Reduce portion size - Prepare foods with less fat - Order carefully at restaurants - Be aware of “hidden fats”  - Lower-fat cuts of meat or poultry - Low-fat or nonfat dairy products, lower-fat versions of high-fat processed foods - Substitute fruits and vegetables for fat-containing snack foods Fat-Related Dietary Supplements Caffeine - Caffeine (theoretically) increases the mobilisation of fats from adipose tissue and at the muscle cell, can change to muscle contractility. Identify sources of dietary - While these effects exist, they are less likely to explain the magnitude of performance changes observed in the fat, and assess an athlete’s current literature. dietary fat intake. - Benefits: nervous system alertness, reduce pain, reduce perception of effort Evaluate dietary Carnitine supplements related to fat - An obligatory component of the transfer process for fatty acids from the bloodstream into muscle mitochondria for metabolism and membrane use as fuel. incorporation - 90% found in muscle Omega-3 Fatty Acids - supports the health of all body systems, including the brain - Limited understanding of omega-3 status in recreational and elite athletes, especially females - Protect lean mass, anti-inflammatory, membrane health and overall wellbeing Summary Week 7 - Supplements Inquiry Question Notes Sports Supplements in the Media Australian freestyle swimmer Shayna Jack tested positive to the banned substance Ligandrol before competing at the world swimming championships in South Korea. Jack said she did not knowingly take Ligandrol but noted it could be found in contaminated supplements. How much money is spent on sports dietary supplements each year? When is a dietary supplement an ergogenic Therapeutic Goods Association aid? - In 2020, the Therapeutic Goods Administration (TGA) amended the Therapeutic Goods (Declared Goods) Order 2019 to provide greater clarity. on the types of sport supplement products regulated by the TGA. Outline which type of - It declares certain sport supplement products to be therapeutic goods where they are represented as being for the supplements are most improvement or maintenance of physical or mental performance in sport, exercise or recreational activity commonly reported as used - Medicine: A product is classified as a medicine if it is represented to be a therapeutic good, likely to be taken for by athletes from around the therapeutic use, or declared to be a therapeutic good. world - Supplements: In Australia, we do not have a separate regulatory category for dietary supplements. All supplements  are either foods or medicines, depending on the supplement's individual features Ergogenic Aid ‘An ergogenic aid is any substance or strategy that improves athletic performance, but the term is often used to describe substances or techniques that increase the production of energy or the ability to do work’. Athletes and use of banned substances A scenario, from a 1995 poll of 198 sprinters, swimmers, powerlifters and other assorted athletes, most of them U.S. Olympians or aspiring Olympians: You are offered a banned performance-enhancing substance, with two guarantees: 1) You will not be caught. 2) You will win. Would you take the substance? Only 3 said no Supplement use by Athletes Supplements are there to support what whole foods can't supply. Describe the Australian AIS Supplement Framework Institute of Sport, Supplement Framework Give examples of dietary or medical supplements from each group and be able to justify why they belong there. 4 different categories: ➔ Group A: strong evidence for use in specific situations for sport, using an evidence based protocol. - Sports drinks: traditional, low sugar, sugar-free, electrolyte drinks. Benefits in providing fuel and effects on motor output when mouth rinsing. - Vitamin D: medical group. Consuming vitamin D, our skin sees that sunlight it's being activated um using the kidney and the liver and then performs a range of different roles. Helps prevent bone injury, chronic musculoskeletal pain, and evidence that it can be put into group A as a medical supplement for protection against upper respiratory viral infections. Quantitative blood measure can be performed to manipulate diet and behaviour. - Caffeine: Reduced perceptual effort and pain, as well as increasing nervous system alertness. Individual improvement varies. 3 mg/kg of body mass. Suggests to start at a lower dose - 1.5mg. ➔ Group B: emerging scientific support, deserving further research. It's to be considered by athletes under research protocol or case managed monitoring situations. - Vitamin C: Plays role in immune health, energy metabolism, collagen synthesis, protection from cell damage (ie oxidative stress). Range of options in whole foods (strawberries, orange, broccoli, etc) - Pickle juice: Cramping associated with long-term dehydration, electrolyte changes. The stimulation of the receptor actually causes a quick decrease in motor outflow. Neuromuscular. 1 ml/kg body mass after the onset. - Fish oil: May improve membrane health, anti-inflammatory, protect lean mass and improve overall well being. EPA (anti-inflammatory) and DPA (brain health) rich forms. Omega 3 index; take a fingerprint, blood sample and based on the red blood cell, we can tell how much presentation of EPA and DH A has been  through the diet in the last 12 weeks. Whole food > supplement. ➔ Group C: scientific evidence indicates no benefit to athletes or no research undertaken. - Magnesium: Proposed benefits include anti-inflammatory, smooth muscle relaxant, bone healing, etc. Most people get enough magnesium in their diet naturally. ➔ Group D: banned or high risk of contamination substances. - A biological passport is when you actually have someone's blood over time and you're looking for changes. - Tests include, growth hormone releasing factors, EPO receptor agonist, growth hormone biomarkers, urine test, isoforms. When to use supplements Describe the IOC decision IOC Consensus Statement making process for the use - It is often difficult to decide which dietary supplements are going to work for individuals, and although there is of a supplement significant scientific and lay information available to sports dietitians today it is valuable that you work through a decision framework whenever you are working with a new athlete or trialling a new supplement. - The International Olympic Committee (IOC) Consensus Statement on Dietary Supplement use in High Performance Athletes provides two very useful and practical decision frameworks sports dietitians should build into their normal practices to aid in deciding what, when, and how much of a dietary supplement you should be recommending. - Flowchart to guide informed decision making and reduce risk of anti doping rule violation during nutritional supplement use. MD, medical doctors. International prohibited substance list Anabolic steroids, peptides, beta agonist diuretics, etc. Anti-doping is wrapped under sport integrity Australia. “To protect Are there dangers to using your sporting career, it’s important to be aware of the 3 A’s”: supplements? 1. (Be) Aware 2. (Do your) Analysis 3. (Take steps to) Avoid AIS Summary Sports foods and supplements can play a minor but important role in the sports nutrition plans of high performance athletes. Sporting organisations, sports science and medicine practitioners, coaches and athletes all contribute to a pragmatic and transparent approach that balances the pros and cons of supplement/sports food use by considering: is it safe? Is it effective? Is it permitted for use in sport? The ABCD Classification system updates and ranks sports foods and supplement ingredients into four groups according to scientific evidence and other practical considerations that determine whether a product is safe, permitted and effective in improving sports performance. Summary Week 8 Water and Electrolytes Inquiry Question Notes Describe the approximate Water amount, distribution, and Most important nutrient. 60% of adult body weight. Electrolyte balance is important. Each athlete must have an roles of body water and the individualised plan. processes by which water movements occur between Electrolytes Involved in Fluid Balance compartments in the body. Cation Anion Sodium (Na+) Chloride (Cl−) Potassium (K+) Bicarbonate (HCO3 −) Calcium (Ca2+) Phosphate (PO4 3−) Magnesium (Mg2+) Protein Define hypohydration, Fluid balance: Considers water volume and solute concentration euhydration, hyperhydration, Euhydration: Adequate water to meet physiological demands and dehydration, and identify Hyperhydration: Excess water, considered temporary avenues of water and Hypohydration: Insufficient water volume sodium intake and loss. Dehydration: Process of body losing water volume Water moves from an area of lower solute concentration to an area of high solute concentration. - Isotonic: The concentration of all solutes is the same on both sides of the cell membrane, so there is no net movement of water. - Hypertonic: The concentration of all solutes is greater outside than inside the cell, so water moves out of the cell, causing the cell to shrink. ECF is hypertonic to ICF. - Hypotonic: The concentration of all solutes is less outside than inside the cell, so water moves into the cell, causing it to swell. ECF is hypotonic to ICF. Water Loss, Intake, Balance, and Imbalance Water loss - Sensible: Faeces (~100ml/day), Urine (~1500ml/day) and Sweat (~100ml/day) - Insensible (~1000ml/day): Avenues of loss that are not normally noticed. Ventilation and inhaled air or nonsweat diffusion through the skin Water balance - Beverages, food, metabolism = ventilation, skin, sweat, urine, faeces Discuss the effect of exercise on fluid balance and the role fluid plays in body temperature regulation, performance, and health during exercise. Thermoregulation and the effect of Exercise on Fluid Balance Physical Activity, Thermoregulation and Sweating - Energy production during physical activity and skeletal contractions produces heat (75%-80% energy lost as heat/sweat) - 1 L of sweat dissipated = 2400 kJ energy lost as heat - The effect of a hot environment is termed "heat stress” - The effect of exercise in a hot environment is commonly referred to as "exertional heat stress". - The core temperature achieved during exertional heat stress is determined by the "heat balance" Heat balance during exercise Heat balance: Difference between heat gain and loss and determines core body temperature. - Body temp tightly regulated 36-37.5 - During exercise increases and often reaches a steady state of 38-39C - Heat Gain: Metabolic heat production and Solar radiation - Heat loss: Convection (moving), Conduction (physical contact, e.g air/water), Radiation (direct temperature) and Sweat evaporation The ability for sweat to evaporate depends on: - Absolute humidity gradient between the skin surface and surrounding air. - Clothing and equipment: Covering the skin prevents convective and radiant heat loss + reduces the effectiveness of sweat evaporation. E.g. ice hockey, American football, and motorsport athletes. Exercise, Sweat, and Water Loss Increase in sweating: Critical mechanism to prevent excessive increase in body temperature. Influential factors: Exercise intensity, Environmental conditions, Clothing and Training status. Physiological effects of elevated core temperature during exercise - Increased fluid & electrolyte losses: Reduced blood plasma/blood volume, Increased blood/plasma osmolality - Increased stress response to exercise: Increased HR but lowered cardiac output, Reduced blood flow to abdominal organs, Increased excitability to CNS > cramping - Risk of exertional heat illness Outline strategies for maintaining fluid balance Effect of Heat on Exercise Performance before, during, and after The effect of hot environments on performance times in track and field running events at major championships. NOTE: exercise;explain the Team sports and the effect of temperature will also be related to the duration, rather than the intensity of oneoff efforts. phenomenon of hyponatremia; and outline a strategy for its prevention in endurance and Sweat Electrolyte Physiology and Assessment in Athletes ultra-endurance athletes. Sweat Gland Function - Human eccrine sweat glands are abundant across the skin surface. - Responsible for the production of sweat - Regulate the sodium and chloride content of the sweat: Minimal evidence that other electrolytes are regulated in any significant manner.  - Secretory duct: Produces precursor sweat, similar composition to plasma - Reabsorptive duct: Reabsorbs some of the Na+ and Cl- in initially secreted sweat - Secreted sweat: Lower [Na+] plasma, similar [K+] Strategies to Replenish Water and Electrolytes Fluid Balance Assessment Measuring the change in Total Body Water (TBW) is very commonly used in sport and exercise nutrition - Indication of the “fluid deficit” - Often expressed as the % of body mass lost. - Dependent on the balance of sweat rate (fluid loss) and the amount of fluid consumed (fluid gain) during activity. Sweat rate is calculated from the change in body weight, after accounting for food and fluid consumption (weight gain) and urinary and faecal losses (weight loss). The remaining weight loss is assumed to be sweat losses. Some assumptions are made when using body weight change to estimate sweat losses: - 1L of sweat ≈ 1kg body mass - Changes in weight due to other factors (e.g. glycogen and body fat reduction due to oxidation, water liberated from glycogen, etc.) are negligible and/or cancel each other out - These assumptions appear to be valid under most exercise conditions Testing Process 1. Void bladder before session 2. Weigh athlete with minimal clothing before & after session (towel dry after exercise) 3. Weigh drink bottle/s and food before and after session 4. If toilet stops taken, weigh the athlete before/after 5. Record session duration and ambient conditions Calculating Total Sweat Loss (fluid deficit): - Total Sweat Loss (mL): = change in body mass (kg x 1000 to convert to grams) + food & fluid intake (g or mL for fluid) - toilet body mass losses (kg x 1000 to convert to grams) - Whole Body Sweat Rate (mL/hr): = total sweat loss / exercise duration (hr) - % body mass loss from fluid: = total sweat loss (kg) - fluid intake (L) / pre-exercise body mass (kg) X 100 Example: Joel has a 1.5 hour soccer match at the local club in the middle of summer: - Weight before match: 79.0 kg - Weight after match: 77.5kg - Fluid consumed during breaks throughout the match: 500mL - Urine losses during the match: 0g Change in body mass (kg): = weight before match (79.0kg) – weight after (77.5kg) = 1.5kg body mass loss Total Sweat Loss (mL): = change in body mass (1.5kg x 1000) + food & fluid intake (500g) - toilet body mass losses (0kg x 1000) = 2000mL Sweat Rate (mL/hr): = total sweat loss (2000mL) / exercise duration (1.5hrs) = 1333mL/hr % body mass loss = Total sweat loss (2kg) – fluid intake (0.5kg) / pre-exercise body mass (79kg) x 100 = 1.9% Fluid Balance Assessment - Considerations A fluid balance assessment is generally considered both valid and reliable for exercise of < 3 hr duration. - The results are specific to the conditions at the time of the assessment: Ambient temperature and humidity, Exercise intensity and duration, Clothing and airflow or Heat acclimation & training status. For exercise of a prolonged nature (e.g. ultra-endurance exercise), loss of substrate for energy production increases body mass loss. − substantial endogenous carbohydrate and fat oxidation. Sweat Loss During Exercise Amount of Sweat Loss During Exercise Sweat loss varies considerably: - ~100 ml daily in nonexercise, temperate conditions - 1 to 2 L/hr if exercising in high temperatures with protective clothing - >2.5 L/hr in prolonged exercise in the heat - Cold environments, exhalation Factors affecting sweat rate: Exercise type, Gender, Ambient Temperature, Relative Humidity, Heat Acclimation, Clothing and Equipment. Exercise-Associated Hyponatraemia Exercise Associated Hyponatremia (EAH) is a serious, potentially fatal condition. Characterised by low blood sodium concentration ( 3 hrs activity): 500-700 mg/L of fluid consumed. Testing required during training - Consuming carbohydrate if appropriate - Avoiding gastrointestinal upset - Customised to consider sweat rate, sweat composition, duration, clothing, and environmental conditions Hydration Goals After Training and Performance - Restoring lost body water to achieve euhydration: 125-150% of the exercise-induced fluid deficit within the first 4 hours post-exercise - Currently no guidelines exist for post-exercise sodium replacement: When sodium deficit is less than 80% of typical daily sodium intake, rapid replacement with salty foods is adequate to restore sodium balance within 24 hours - Consuming adequate carbohydrate to fully restore muscle glycogen - Consuming adequate protein to build and repair skeletal muscle - Avoiding gastrointestinal upset Sports drinks during and after exercise: - Helps prevent dehydration induced by exercise  - Flavour of sports drink encourages greater fluid consumption - Electrolytes helps the body absorb and retain fluid - Isotonic for easy absorption across the gut - Ideal concentration of CHO and electrolytes means that sports drinks are ideal for replenishment of fluid and fuel Summary Week 9 - Readings Inquiry Question Notes “Practical Approaches to Nutrition for Female Athletes” Female athletes often receive misguided nutritional advice, leading to inadequate caloric intake. There’s a lack of sports research specific to women, often resulting in the incorrect application of male-centric findings to female athletes. Summary Week 10 - Nutrition for Team sport Inquiry Question Notes Gain an understanding of the Types of team sports types of team sports and Strength and power sports: rugby union and rugby league some unique considerations Endurance based sports: AFL, hockey and soccer Batting sports: cricket, baseball, softball Court sports: basketball and netball - Generally divided into 2 types – field and court - Repeated high intensity sprint activity with short or long periods of rest in between - Speed, strength and agility - Combination of anaerobic and aerobic energy systems - Carbs are usually main source for fuel Considerations in team sport Science and physiological aspects = important. BUT the culture of the team sport and how you can adapt your personality and approach to fit within that culture = also important. ➔ Small (and important) cog in very large machine ➔ Role of the sports dietitian within a team sport environment - Life skills for development players - Individual nutrition education and advice - Data collection, monitoring and feedback - Food service: environment promotes clean eating - Training and competition fuel and fluid delivery systems - Collaboration with coaches and support staff - Professional development and reflection Understand how nutrition How nutrition can impact performance can impact performance in a - Team is comprised of individual athletes – not all advice will be the same eg GI issues team sport environment - Prevent or delay fatigue = better training outcomes - Body composition – leaner is not always better for performance; targets should not the same for each athlete - Recovery nutrition – particularly with sports like basketball with more than 1 game per week, pre-season training – back-to-back sessions - Providing food options and education for them to make good choices around food - Hydration strategies and heat management: ice towels, menthol etc - Health and well-being – not just performance: ie during retirement ensuring their health is a priority - Nutrition for injury – prevention + return to play strategies: eg protein smoothie for muscle recovery - Education for fellow staff and coaches on nutrition impact Factors influencing nutrition advice: rules, Field size, Duration and frequency of matches, season length, Training phase and substitutions. Understand some of the Requirements for training and competition requirements for training and ➔ Very individual: can depend on body composition, position, training requirements (speed needed, distance running) competition and ways to ➔ Nutrition and hydration for the climate assess if athletes are ➔ Level of athlete - development VS elite meeting these - Development – will need advice around good base diet - Elite – individual screening/testing, hydration, fueling and recovery strategies ➔ Duration of training and games – number of sessions in a day Meeting requirements ➔ Energy - Important for performance and recovery and can compromise both health and performance if chronically low - Training Days: Studies show that many team sports athletes are not meeting energy requirements - Competition Days: Intake was higher than training days across many sports and for the days leading into competition ➔ Carbohydrates - Intake can vary a lot from guidelines – typically lower - Many athletes opting for dieting higher in protein and fat in place of carbs - Typically close to 3-5g/kg/day ➔ Protein - Intake generally exceeded recommendations - >2g/kg/day (ISSN recommendations) - High intakes generally considered for athletes aiming to reduce body fat - Recovery: carbs:protein 3-4:1 – 0.2-0.5g/kg BW protein How do you know if players are meeting requirements ➔ Body composition - Lean mass – protein and energy requirements and distribution - Body fat – overall energy intake, food diary, photos etc. involve partners or parents, cooking classes ➔ Immunity and health – bloods, energy and macronutrient intake, micronutrients intake, supplementation ➔ Wellness markers – mood, stress/anxiety, soreness, sleep duration and quality, fatigue ➔ Performance in training: struggling at training prompts to reassess if they are meeting requirments ➔ Injuries Planning and implementation across the season Pre-Season Gain some insight into ways Usually the busiest time for dietitians and the most demanding time physically for athletes. Opportunity to work on specific a dietitian might plan and goals: Life skill development, Collection of assessment data, Trialling nutrition strategies, Manipulating body comp, implement nutrition Pre-planning logistics to the season ahead, and Hydration monitoring and individual plans. strategies across the season During Season - Match day nutrition and hydration education - Match day nutrition timelines - Systems to ensure nutrition and hydration are integrated without the dietitian present (other staff can help with this) - Illness and injury referral systems and protocols - Concussion protocol and follow up Off Season - Review of the season and planning for next season - Body comp manipulation for some players can happen in the off season (bigger goals) - Refine systems and make changes for next season - Injured players with off season rehab programs Catering Understand how catering Depends on budget, travel, availability of cooking facilities and time constraints. Aiming to ensure everyone within the team and food service works in a can get what they need at a meal or snack is a priority when menu planning. team setting - Buffets – practical and allow players to adjust their portions – education needed - Pre-packed meals good for on the go or quick lunches between sessions - Team mealtime is a good chance to involve yourself and for players to ask questions - Keeping fridge and pantry stocked with good options to access during training Supplement programs Gain some insight into how a supplement program might be run within a team sport setting Summary Week 11 Inquiry Question Notes Describe the concepts of Introduction to eating disorders normal eating, disordered “Normal” Eating eating, and eating disorders. An eating pattern that: Compare and contrast - Is flexible and not obsessive anorexia nervosa, bulimia - Is moderate and balanced nervosa and binge eating - Is based on internal hunger and fullness cues disorder - Involves some constraint, but not reckless abandon or overly strict discipline - Consists of consuming foods that are nutrient rich as well as eating some foods that might have a low nutrient content “Normal eating is being able to eat when you are hungry and continue eating until you are satisfied. It is being able to choose food you like and eat it and truly get enough of it – not just stop eating because you think you should. Normal eating is being able to use some moderate constraint in your food selection to get the right food, but not so restrictive that you miss out on pleasurable foods. Normal eating takes up some of your time and attention, but it keeps its place as only one important area of your life. Normal eating is flexible” Satter, 1987.  Normal eating in athletes: Athlete’s diets often require careful planning. Diets may become more rigid at particular times i.e. competition season. Normal eating amongst athletes is characterised by discipline, not obsession and inflexibility. - Ensure adequate intake of macronutrients - Minimise excessive caloric intake that may result in weight gain Eating Disorders Eating disorders are defined as serious, complex and potentially life-threatening mental illnesses characterised by disturbances in behaviours, thoughts and feelings towards body weight/shape and/or food and eating. Eating disorders represent a substantial deviation from normal eating. There are different types of eating disorders that someone can be diagnosed with, according to the DSM-5 (classification and assessment tool for mental disorders). Anorexia Nervosa Bulimia Nervosa Binge Eating Disorder (BED) Caloric restriction that results in a Recurring binge eating episodes coupled Large amount of food in short time + significantly low body weight for with compensatory behaviours in attempt loss of control of eating behaviours. age. to prevent weight gain: Self-induced Associated by having three or more of - Intense fear of gaining vomiting, Laxatives, Diuretics and/or the following: weight enemas, Fasting or Excessive exercise. - More rapid eating than normal - Distorted body image - Prevalence is difficult to estimate - Eating until uncomfortably full Behaviours to prevent weight gain due to lack of treatment and - Eating large amounts when not even at a significantly low weight: detection physically hungry - Restricting type - Eating alone because of - Binge-eating/purging type feeling embarrassed - Feeling disgusted with oneself, depressed, or guilty afterward OSFED/USFED Exercise Dependence Not all of the criteria for diagnosis Exercise addiction or compulsive ^^All these discussed eating disorders of the previous eating disorders exercise. Adverse impacts on are characterised by poor body image, have been met. Symptoms are quality-of-life and health. Ie acute injuries, distortion of one’s own body, and fear still clinically significant and over-training. Often found in conjunction of weight gain. Outline changes in eating problematic for daily functioning with eating disorders and disordered and exercising patterns over and health eating. Mechanism to control weight. time that may put athletes at risk for disordered eating and eating disorders. Disordered eating Disordered eating behaviours are those that are not considered to be normal or optimal, and have some characteristics of State the prevalence of eating disorders but not enough to be a diagnosed eating disorder. disordered eating and eating - Include yo-yo dieting, restrictive eating patterns, removing whole food groups, fasting and then feasting patterns, disorders in male and female rigid eating patterns, compulsive or dependent exercise. athletes and explain the - These behaviours are connected to attempts to lose weight or change body shape. distinctions between athletes with eating disorders and Prevalence of eating disorders those who are training - In the general population, throughout their lifetime , ~8.4% women and 2.2% of men will experience an eating intensely but do not have a disorder. disordered eating pattern. - In athletes, this prevalence is much higher: modest estimate of 14-16% of athletes will experience an eating disorder in their lifetime. - Estimates of disordered eating amongst athletes range from 6-45% in females and as high as 19% in males Risk Factors for Eating Disorders  - Genetics (psychiatric) - Family environment – family history of eating disorders/disordered eating, dieting, obsessive food talk, children not modelled healthy food behaviours - Personality – perfectionistic, obsessive, poor self-esteem, need to maintain control. - Trauma/Complex PTSD - Cultural influences – “thin ideal” - Major life events, changes or loss. - Athletics/sports with thin bodies and weight requirements Engaging in dieting (food restriction to intentionally lose weight) is the single biggest predictor for the onset of an eating disorder. Health consequences of eating disorders - Low energy availability (starvation) > menstrual and endocrine disturbances, low bone mineral density, impaired immune function, intense fatigue - Nutritional deficiencies > commonly iron-deficient anaemia. - Electrolyte imbalances and dehydration – impaired cardiac function, low blood pressure - Gastrointestinal problems – bloating, constipation, diarrhoea, impaired intestinal function - Dental problems if purging - Impaired mood, cognitive and psychological functioning due to lack of nu