Transcript FN3373-Lecture-2-OWL-Physiology-of-Aerobic-Anaerobic

chapter
1
Physiology of
Aerobic & Anaerobic
Exercise
Introduction
to
Nutrition for
Exercise and
Prof Jennifer Broxterman, RD, MSc
Health
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
Oxidative
Phosphorylation
ATP
Characteristics of the 3 Energy Systems
Speed of
Action
Amount of
ATP
Replenished
Duration of
Action
Creatine
Phosphate
Anaerobic
Glycolysis
Very Fast
Very Small
Very Short
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
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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 highintensity exercises (power events)
Creatine Phosphate &
ADP Rephosphorylation
The Creatine Shuttle
Energy System 2
Anaerobic
Glycolysis
Glucose
GLYCOLYSI
S
2 ATP
2 Pyruvic Acid molecules
Aerobic
Metabolism
CO2 + H2O
If Oxygen is Present
36-38
ATP
If Oxygen is Absent
Anaerobic
Metabolism
Lactic Acid
The Anaerobic Glycolysis
Energy System
Anaerobic Glycolysis
Cori Cycle
Energy System 3
Oxidative
Phosphorylation
Glucose
GLYCOLYSI
S
2 ATP
2 Pyruvic Acid molecules
Aerobic
Metabolism
CO2 + H2O
If Oxygen is Present
36-38
ATP
If Oxygen is Absent
Anaerobic
Metabolism
Lactic Acid
Cellular Respiration Overview
C6H12O6 + 6O2
(glucose)
6CO2 + 6H2O + Energy
(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