Introduction to Nutrition for Exercise and Health chapter 1 Physiology of Aerobic & Anaerobic Exercise Introduction to Nutrition for Exercise and Health Prof Jennifer Broxterman, RD, MSc FN3373: Nutrition for Physical Activity Lecture 2 Author name here for Edited books

What Fuels Physical Activity?

ATP

Hydrolysis of ATP

ATP & Energy Use by Exercising Muscles

Rephosphorylation of ADP to Form ATP

Energy Systems that Replenish ATP Creatine Phosphate Anaerobic Glycolysis ATP Oxidative Phosphorylation

Characteristics of the 3 Energy Systems Speed of Action Amount of ATP Replenished Duration of Action Creatine Phosphate Very Fast Very Small Very Short Anaerobic Glycolysis Fast Small Short Oxidative Phosphorylation Very Slow Large Very Long

Energy System 1 Creatine Phosphate

Creatine Phosphate Energy System

The CrP Energy System Rephosphorylates ADP to ATP Rapidly Anaerobic reaction If [ATP] in a muscle ↓ there is an accompanying ↑ in ADP in the cell ↑ in the activity of CK, allowing the reaction to proceed faster CrP is stored in very small amounts At very high-intensity exercise it takes ~ 5-10 seconds for CrP in the muscle to be depleted and fatigue to set in

Characteristics of the CrP Energy System One chemical step Catalyzed by creatine kinase (CK) Very fast reaction One ATP per CrP molecule 5-10 second duration Anaerobic Fatigue associated with CrP depletion Predominant energy system in very high-intensity exercises (power events)

Creatine Phosphate & ADP Rephosphorylation

The Creatine Shuttle

Energy System 2 Anaerobic Glycolysis

2 Pyruvic Acid molecules Glucose GLYCOLYSIS 2 ATP 2 Pyruvic Acid molecules Anaerobic Metabolism Aerobic Metabolism If Oxygen is Present If Oxygen is Absent 36-38 ATP Lactic Acid CO2 + H2O

The Anaerobic Glycolysis Energy System

Anaerobic Glycolysis

Cori Cycle

Energy System 3 Oxidative Phosphorylation

2 Pyruvic Acid molecules Glucose GLYCOLYSIS 2 ATP 2 Pyruvic Acid molecules Anaerobic Metabolism Aerobic Metabolism If Oxygen is Present If Oxygen is Absent 36-38 ATP Lactic Acid CO2 + H2O

Cellular Respiration Overview C6H12O6 + 6O2 6CO2 + 6H2O + Energy (glucose) (heat and ATP) The energy in one molecule of glucose yields 36 ATP Aerobic respiration involves a series of 3 reactions: Glycolysis Krebs Cycle Electron Transport Chain

Glycolysis

Oxidative Phosphorylation Energy System

Glycolysis, Krebs Cycle, Electron Transport Chain of Oxidative Phosphorylation

Macronutrients as Fuel Sources during Exercise

Beta Oxidation

Respiratory Exchange Ratio

Respiratory Exchange Ratio

Respiratory Exchange Ratio

RER Chart