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Physiology of Exercise

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					Energy for Exercise
Chapter 11

Biological Work
Muscle Contraction * Digestion & Absorption Gland Function Establishment of Gradients Synthesis of New Compounds

Energy
First Law of Thermodynamics Conservation of Energy – Energy can not be “Created” or “Destroyed” Our body simply transforms energy

AdenosineTriPhosphate
“Fuel” for all processes in body
Food energy  Rebuild more ATP ATP – Chemical, Potential Energy Phosphate bonds: “High Energy”

Phosphorylation
ATP  ADP + P + ENERGY
ATP Re-synthesis

CP  C + P + ENERGY

Aerobic vs. Anaerobic Energy
Aerobic: O2 requiring energy production Anaerobic: No O2 required for energy

Anaerobic Energy
ATP stores Creatine Phosphate Anaerobic glycolysis

ATP – CP Energy System
Small amount of ATP stored
85 g in whole body Must be re-synthesized CP: quick energy for ATP rebound


CP stored in larger quantities

All out Exercise – 5 to 8 seconds

ATP – CP Energy System Increasing [ATP – CP]
Exhaust ATP – CP stores  Adaptation Creatine Monohydrate supplementation

Creatine Monohydrate
What it does
Increases intracellular stores creatine phosphate. Increases anaerobic capacity Decreases accumulation of lactic acid* Delays onset of muscular fatigue Increase water retention in muscle*

Creatine Monohydrate What it does NOT do:
Make you stronger / faster Increase muscle mass Decrease body fat % Increase aerobic capacity

Creatine Monohydrate
Side Effects?
Muscle cramps, pulls, strains, etc.

Dehydration Liver / Kidney stress Atrophy of bank account

Anaerobic Glycolysis
6-Carbon Glucose  two 3carbon pyruvic acid Occurs in “watery medium” 5% of total ATP from glucose

Anaerobic Glycolysis
1.) Chemical bonds broken 2.) H+ atoms are striped 3.) Two ATP formed

Glucose
Energy H+

Anaerobic

ATP
Fatty Acids Amino Acids

Pyruvic Acid (2)

Lactic Acid (2)
Inter Cellular Fluid Mitochondria

CO2
Acetyl Co-A (2)

&

H+

Aerobic

CO2

Krebs Cycle

Energy

ATP
To ETC

H+

Aerobic Glycolysis
Pyruvic Acid  Acetyl CoA Acetyl CoA  Mitochondria Krebs Cycle
Chemical breakdown of Acetyl CoA & fragments of proteins & Lipids Frees H+ & Produces CO2 Generates small Amount of ATP

Aerobic Glycolysis
Krebs Cycle
H+  Electron Transport Chain

ETC
H+ + Oxygen  H20 + Energy

Energy

ATP

Krebs

Cycle
H+

CO2

Electron Transport Chain 2H+ +

ATP

O

--

= H2O

Energy Transfer Systems and Exercise
100%

% Capacity of Energy System
10 sec

Anaerobic Glycolysis

Aerobic Energy System

ATP - CP

30 sec

2 min

5 min +

Aerobic Capacity
Capacity for aerobic resynthesis of ATP

O2 Uptake During Exercise
Oxygen Uptake: Use of oxygen by the cells for aerobic metabolism.
VO2 – ml O2/Kg/min. VO2 max = Max O2 uptake possible by individual Quantification of Aerobic Capacity

VO2max
VO2max : Max Oxygen Uptake
Further increases in exercise intensity (further energy requirement), results in NO increase in VO2.
Additional energy is produced via anaerobic glycolysis

Exercise of Increasing Intensity
Oxygen Consumption (ml/kg/min)

60 50 40 30 20 10 0 Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 Stage 6
VO2max

What Effects Energy Capacity ?
Diet (Glycogen stores, Metabolic State) Training
Type of training, Altitude

Gender Supplements / Drugs GENETICS

Energy Systems and Exercise

Anaerobic / Aerobic Energy is always being produced
Exercise intensity / duration determines the ratio

Can be estimated with RER

RER aka RQ
RER = CO2 produced / O2 consumed Carbohydrate: Hydrogen to Oxygen (2:1)  RER = 1.00
C6H12O6 + 6O2  6 CO2 + 6 H2O

Lipid: Hydrogen > Oxygen (2:1)  RER = 0.7

Energy

ATP

Krebs

Cycle
H+

CO2

Electron Transport Chain 2H+ +

ATP

O

--

= H2O

Lactic Acid
Byproduct of Anaerobic Metabolism.
Glucose Energy H+

ATP

Pyruvic Acid (2)

Lactic Acid (2)

Lactic Acid
Causes Fatigue
Irritation of local muscle Decreased pH of cellular environment & bloodstream

Training increases lactate tolerance and decreases lactate formation at any given workload (by 20-30%)

Blood Lactate Threshold
Point at which lactate begins to dramatically increase in the blood stream. (55% VO 2max)
Fatigue increases exponentially Caused by increase in anaerobic metabolism  Lactate production

Effect of Training on Blood Lactate / Lactate Threshold

[Blood Lactate] 25%

Untrained Trained LT

LT

50% 75% Percent of VO 2 max

100%

What Effects Lactic Threshold ? GENETICS
Aerobic Capacity Fiber Type

Training
(adaptations..next slide)

Physiological ’s with Training ( Lactic Acid Build Up)  in capillaries ( Density)  aerobic enzymes  mitochondria (# and size)  Pain tolerance to Lactic Acid

Blood Lactate Threshold
Lactate appearance in the bloodstream
POWERFUL predictor of aerobic exercise performance! Higher LT = Better performance; less LA buildup, less fatigue

Lactate Processing
Cori Cycle
Muscle Cell
Glucose

Liver
Glucose / Glycogen

Pyruvate
Lactate

Pyruvate Lactate

Recovery
Recovery Oxygen Uptake
VO2 stays  after exercise
Replenish ATP – CP Reload hemoglobin Supply elevated energy needs to cardiovascular system o Increased O2 need 2 heat


Recovery (cont.)
Lactic Acid Removal (Heavy Exercise)
Cori cycle Reconversion in muscle cell


Lactate  Pyruvate  Glucose

Few seconds – few hours

Recovery (cont.)
Light activity accelerates recovery
Increased blood flow to muscle, liver, and heart


All can oxidize lactate for energy


				
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posted:11/5/2009
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