Exercise Physiology Quiz

Energy Systems and Metabolism in Athletes

• The presentation is about energy systems and metabolism in athletes.
• The presenter is Cleonara Yanuar Dini, S.GZ., M.Sc., RD from the Nutrition Science Department of UNESA.
• The presentation covers carbohydrate, lipid, and protein metabolism.
• It also includes system energy, specifically ATP-PCr, glycogen, glucose, fatty acids, and protein.

How Energy Systems Contribute to Our City

• This slide shows images of cityscapes at night.
• The presentation probes the role of energy systems in urban development.

What's Makes Them Different?

• The presentation compares Usain Bolt and Eliud Kipchoge.
• It highlights their different athletic qualities and specialties.

Carbohydrate Metabolism

• Carbohydrates are broken down into glucose for energy production.
• Glycolysis: Breakdown of glucose into pyruvate, producing a small amount of ATP.
• Citric Acid Cycle: Pyruvate is further oxidized, generating more ATP and electron carriers.
• Electron Transport Chain: Electron carriers transfer electrons to produce large amounts of ATP.

Lipid Metabolism

• Fat is a concentrated energy source, broken down into fatty acids and glycerol.
• Glycerol: Converted to glucose through gluconeogenesis.
• Fatty Acids: Undergo beta-oxidation, producing acetyl-CoA which enters the citric acid cycle.
• Ketone Bodies: Formed during prolonged fasting as an alternative energy source for the brain.

Protein Metabolism

• Protein is broken down into amino acids for energy or tissue repair.
• Deamination: Amino acids lose their amino group and enter energy pathways.
• Krebs Cycle: Intermediates used in the citric acid cycle, producing ATP.
• Gluconeogenesis: Some amino acids converted into glucose.

System Energy

• ATP-PCr: Short-term energy source
• Glycogen: Energy storage form of glucose
• Glucose: Simple sugar, used for energy
• Fatty Acids (Triacylglycerol): Long-term energy source
• Protein: Used as energy when other sources are depleted

How ATP Produces Energy

• ATP (adenosine triphosphate) is the primary energy currency of cells.
• ATP releases energy by breaking a phosphate bond, resulting in ADP (adenosine diphosphate) and inorganic phosphate (Pi).

System Phosphagen

• System fosfagen (ATP-PC): uses ATP and creatine phosphate (CP) for short bursts of exercise.
• Process involves the hydrolysis of ATP and utilizes high energy phosphate bond of creatine phosphate to regenerate ATP.
• Key enzymatic reactions include creatine kinase and adenylate kinase.

Lactic Acid and Oxidative Systems

• Lactic acid system: Uses carbohydrates for rapid energy production via anaerobic glycolysis, good for high-intensity workouts like sprints.
• Oxidative system: For prolonged endurance activities relying on aerobic metabolism for ATP. Uses glucose and fats for energy.

Product of Energy from Glucose (Glycolysis)

• Glucose and glycogen are converted into pyruvate during glycolysis.
• Pyruvate can be converted to lactic acid via lactate dehydrogenase.

Product of Energy of Glucose (Citric Acid Cycle and Electron Transport Chain)

• The Citric Acid Cycle and electron transport chain occur in mitochondria.
• These processes generate a significant amount of ATP from the breakdown of carbohydrates and fats.

Glycogen

• Glycogen is the storage form of glucose in the liver and muscles.
• It's a crucial energy reserve for short-term and prolonged exercise.
• Glycogen stores in the liver primarily support blood glucose levels throughout the day.
• Muscle glycogen supports energy needs for localized muscle contraction without impacting blood glucose.

Breakdown of Glycogen (Glycogenolysis)

• Glycogenolysis is the breakdown of glycogen into glucose-1-phosphate.
• This process is facilitated by glycogen phosphorylase.
• Branch points in glycogen are removed by debranching enzymes.

Lactate Concentration Post-Exercise

• Lactate concentration increases with higher exercise intensity and VO2 max (maximum oxygen uptake).
• Trained athletes have a higher lactate threshold, allowing them to tolerate higher lactate concentrations before fatigue sets in.

Lactate Concentration in Cyclists

• Data regarding lactate concentration (mmol/L) is presented for various cyclist workout intensity levels.

Cori Cycle

• The Cori cycle describes the metabolic pathway where lactate produced in muscle tissue is transported to the liver.
• Here, lactate is converted back to glucose and returned to the muscles, completing a cycle crucial for energy production and regulation.

Fatty Acids/Triacylglycerol

• Fatty acids are converted to acetyl-CoA through beta-oxidation in the mitochondria.
• Acetyl-CoA enters the citric acid cycle for energy production.
• Fatty acids from triglycerides are metabolized to provide energy, particularly during prolonged exercise.

Conversion of Energy From Fat

• Fat is stored in the body as triglycerides, and is broken down into glycerol and fatty acids.
• Glycerol produces glucose, which can be used in glycolysis or gluconeogenesis.
• Fatty acids undergo beta-oxidation to generate acetyl-CoA, which enters the citric acid cycle and the electron transport chain to produce ATP and water.

Protein and Metabolism

• Some amino acids support gluconeogenesis during exercise by producing intermediates (pyruvate, oxaloacetate and malate).
• Other amino acids are ketogenic, yielding acetyl-CoA or acetoacetate that cannot be used for glucose synthesis.

Energy Stores

• Table shows energy stores (liver glycogen, muscle glycogen, blood glucose, fat, protein) with their respective mass, energy content, and duration of exercise.

How Exercise Type Affects Metabolism

• Short duration exercise relies on ATP stores and creatine phosphate, followed by anaerobic glycolysis.
• Prolonged exercise relies on aerobic processes, utilizing various fuel sources like carbohydrates and fats.

Aerobic and Anaerobic Systems

• Percentage contribution of energy systems (aerobic, anaerobic, ATP-PC, and Glycolysis) during various exercise durations are described in the graphs and tables.

Oxygen Consumption During Exercise

• Oxygen consumption (VO2) changes during various exercise intensities.
• Steady-state VO2 is the energy requirement of the activity.
• Graph explains the oxygen consumption and recovery during various types of exertion.

Estimate of ATP Generation from Different Fuel Sources

• Table 7.1 shows the relative contributions of various fuel sources (phosphocreatine, anaerobic glycolysis, aerobic glycolysis, glycogen and triacylglycerols) to ATP production in different exercise durations.

Metabolic Response to Exercise

• The presentation covers the metabolic responses to various types exercise.
• The presentation details the metabolic changes in carbohydrates, fats, proteins, enzymes and oxygen in relation to endurance training, resistance training and other exercise types.

Metabolic Response to Physical Exercise (Carbohydrate, Fat, Protein)

• Carbohydrates provide short-term energy.
• Fats provide long-term energy.
• Protein provides energy when other sources are depleted.

Metabolic Response to Exercise (Enzymes)

• Glycogen phosphorylase, phosphofructokinase, lactate dehydrogenase (LDH), and malate-aspartate shuttle enzymes are activated with exercise.
• Enzymes of beta-oxidation and the Krebs cycle also increase with training, increasing the rate of fuel metabolism.

Metabolic Responses to Exercise - Oxygen Utilization

• Oxygen utilization increases with aerobic endurance training but not with dynamic resistance training.
• Myoglobin concentration also increases with aerobic training.
• There are oxygen deficits and drifts occurring during exercise and recovery stages.

Metabolic Response to Exercise (Cardiovascular)

• Cardiac output reflects the functional capacity of the cardiovascular system.
• Heart rate and stroke volume determine the heart's output capacity.
• Cardiac output increases with intensity.

Metabolic Response to Exercise (Muscle)

• Endurance athletes have normal-sized muscle fibers with increased slow-twitch fiber enlargement and glycogen content.
• Weightlifters show enlarged fast-twitch fibers and glycogen content increase.
• With aerobic training, the number of capillaries around each muscle fiber increases by 20–30%.

Metabolic Response to Exercise (Mitochondria)

• Training promotes an increase in the number and size of mitochondria, enhancing the capacity for fuel oxidation.

Conclusion

• The presentation is an overview of the metabolic changes associated with different types of athletic training.
• The presentation highlights the crucial role of energy systems in the performance and adaptation.