Nutrition and Sports Final Study Guide Spring 2015 1 Know the legal limit for urinary caffeine concentration and how intake affects the measurement Caffeine is on the banned substance list o Banned if approximately 12016 cups of coffee o Banned for IOC if 12 mcg ml of urine o Banned for NCAA if 15 mcg ml of urine The amount that one intakes caffeine and the time that one intakes caffeine can affect performance 2 What are the performance benefits of caffeine consumption and the required dosage Caffeine enhances performance via the effect on the central nervous system increased alertness Increases Resting Energy Expenditure 7 15 Enhances fat mobilization and possibly use important for endurance exercise o Increases lipolysis 13 Resting FFA and glycerol increased suggesting adipose tissue lipolysis May help with endurance exercise because of the glycogen sparing effect Helps with high intensity exercise Power improves The required dosage is approximately 2 4 cups of coffee o 200 400 mg 3 6 mg kg 3 Explain caffeine s mode of action Adenosine inhibition o Caffeine hooks up to adenosine receptor instead of adenosine Results in CNS excitation which changes BP HR and mood Metabolic stimulation to increase energy expenditure Catecholamine release increase EE and CHO and Fat oxidation o Adenosine inhibits NE release o More NE available in synapse CNS Stimulation o Increase excitability of nervous system o Decrease pain with muscle contraction PDE phosphodiesterase inhibition o PDE inhibits intracellular signaling cAMP o Caffeine can thus prolong the action of cAMP by stopping PDE 4 Explain green tea s mode of action 5 Explain beta alanine s mode of action Beta Alanine o Amino acid derivative o Synthesized naturally in liver o Increases carnosine concentrations within skeletal muscle Histidine BA Carnosine is a buffer during high intensity exercise o Beta Alanine most likely works by delaying fatigue through intra muscular H buffering 6 What does HMB stand for HMB is Beta Hydroxy Beta Methylbuterate 13 o It is a bioactive metabolic byproduct of leucine metabolism 7 What are the effects of combing caffeine and green tea There is evidence that this combination has a significant impact on resting metabolism and shift fuel to a greater reliance on fat There has also been evidence that this combination increases fat oxidation Therefore caffeine and green tea can burn fat 8 Explain when buffering solutions may be appropriate and why What is the typically recommended dosing guideline Do they work The bicarbonate aspect of the body s buffering system provides a major line of defense against increased intracellular H concentration Maintaining high levels of extracellular bicarbonate rapidly releases H from cell and delays the onset of intracellular acidosis Increasing bicarbonate alkaline reserves might enhance anaerobic exercise performance because increased H concentration in intense exercise reduces the calcium sensitivity of the contractile proteins which impairs muscle function Buffering solutions are appropriate during anaerobic exercise Doses of at least 0 3 g kg facilitate H efflux from the cell Long term bicarbonate ingestion 0 5 g kg for 5 days is also beneficial 9 Why is EPO use both beneficial and potentially dangerous EPO Epoietin synthetic erythropoietin Increases hemoglobin and hematocrit of rbc in 100 mL of blood Causes significant improvement in endurance exercise performace EPO is blood doping Increases viscosity of blood which can be fatal Can cause stroke heart attack heart failure Blood doping is illegal Increase in RBC and hemoglobin increases oxygen carrying capacity of blood o Which increases aerobic performance Effective in improving VO2max and endurance performance 10 Explain the normal physiological status of creatine sources and function during exercise and recovery 13 Creatine is naturally produced in the liver and kidneys 95 stored in skeletal muscle It is found in the diet from fish and beef Creatine in diet moves into blood and then into muscle Creatine can improve exercise performance Creatine can improve exercise performance lasting 30 secs Creatine improves muscular endurance 11 Know the typical creatine supplementation dosing strategy its effect on total Cr and the resynthesis of PCr How does CHO influence supplementation Typical creatine supplementation dosing is 5 6 grams per day 0 06 to 0 08 g kg BW o Split dosing is now recommended Loading phase is typically 20 grams for 5 days o Only time you don t need to worry about this is if you don t care how fast you saturate o Or if you re an athlete who s worried about putting weight on For both of these you can take smaller dose in a longer period of time Creatine supplementation increases stored doses of creatine phosphate in the muscle o So when ADP needs help to make ATP the creatine phosphate donates the phosphate and your left with Phosphocreatine PCR ADP and the enzyme creatine kinase results in ATP and creatine If you increase creatine and phosphocreatine in muscle you increase pre exercise phosphocreatine availability o This in turn decreases dependence upon glycolysis because you can carry out the ATP PCR system for a o Therefore you would decrease lactate production the hydrogen ion changes because you haven t used free creatine and ATP little bit longer glycolysis yet o Therefore your pH will stay a little bit elevated or maintained for a little bit longer o Which delays the onset of fatigue during activities o Which finally increases muscular performance Taking creatine with CHO causes a better surge in insulin to drive the product into the muscle itself o So creatine with CHO compared to just creatine alone improves performance 12 What are the effects of creatine supplementation on performance in activities at different durations intensity dependent variable Has creatine been effective in longer duration activity Creatine improves endurance and anaerobic performance Creatine also improves exercise performance lasting 30 secs 13 13 How has Cr been shown to affect body composition Creatine improves total body mass and fat free mass Creatine doesn t change fat mass and percent body fat So creatine is useful for improving muscle but not necessarily our body fat levels 14 Does creatine shut down your kidney s Creatinine the byproduct of creatine and kidney function are related If you have an abnormal production of creatinine you might have some renal kidney issues Creatine doesn t have direct effect on