Exercise physiology mpb 326
Download
1 / 47

Exercise Physiology MPB 326 - PowerPoint PPT Presentation


  • 111 Views
  • Uploaded on

Exercise Physiology MPB 326. David Wasserman, PhD Light Hall Rm 823 3-7336. The Remarkable Thing about Exercise. The Great Debate. Top-down Feedback control. Energy Metabolism and the Three Principles of Fuel Utilization.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Exercise Physiology MPB 326' - shana-vasquez


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Exercise physiology mpb 326

Exercise PhysiologyMPB 326

David Wasserman, PhD

Light Hall Rm 823

3-7336



The great debate
The Great Debate

  • Top-down

  • Feedback control



Exercise physiology mpb 326
The need for energy starts when calcium is released from the sarcoplasmic reticulum of contracting muscle


The working muscle
The Working Muscle sarcoplasmic reticulum of contracting muscle


Energy for contraction
Energy for Contraction sarcoplasmic reticulum of contracting muscle


Muscle relaxation requires energy too
Muscle relaxation requires energy too! sarcoplasmic reticulum of contracting muscle


Where does this atp come from

Where does this ATP come from? sarcoplasmic reticulum of contracting muscle


Sources of atp
Sources of ATP sarcoplasmic reticulum of contracting muscle

Stored in muscle cell (limited)

Synthesized from macronutrients

Common Processes for ATP production

Anaerobic System

a. ATP-PC (Phosphagen system)

b. Anaerobic glycolysis (lactic acid system)

Aerobic System

a. Aerobic glycolysis

b. Fatty acid oxidation

c. TCA Cycle


Exercise physiology mpb 326

ATP-PCr (Phosphagen system) sarcoplasmic reticulum of contracting muscle

Stored in the muscle cells (PCr > ATP)

ATP + H2O  ADP + Pi + E (ATPase hydrolysis)

PCr + ADP  ATP + Cr (creatine kinase reaction)

ADP + ADP  ATP + AMP (adenylate kinase)

PCr represents the most rapidly available source of ATP

a) Does not depend on long series of reactions

b) No O2 transportation required

c) Limited storage, readily depleted ~ 10 s


Glycolysis
Glycolysis sarcoplasmic reticulum of contracting muscle

Glucose + 2 ADP + 2 Pi + 2 NAD+

2 Pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O


Lactate dehydrogenase
Lactate Dehydrogenase sarcoplasmic reticulum of contracting muscle

Hypoxic conditions

Pyruvate + CoA + NADH + H+

Lactate + NAD+


Pyruvate dehydrogenase
Pyruvate Dehydrogenase sarcoplasmic reticulum of contracting muscle

Lots of Oxygen

Pyruvate + CoA + NADP+

Acetyl-CoA + CO2 + NADPH


Pyruvate dehydrogenase1
Pyruvate Dehydrogenase sarcoplasmic reticulum of contracting muscle

Pyruvate + CoA + NADP+

Acetyl-CoA + CO2 + NADPH


Tca cycle
TCA Cycle sarcoplasmic reticulum of contracting muscle

Acetyl-CoA + 3 NAD+ + FAD + GDP + Pi + 2H20

CoASH + 3 NADH + 3H+ + FADH2 + GTP + 2CO2


Beta oxidation of fatty acids
Beta Oxidation of Fatty Acids sarcoplasmic reticulum of contracting muscle

7 FAD + 7 NAD+ + 7 CoASH + 7 H2O + H(CH2CH2)7CH2CO-SCoA

8 CH3CO-SCoA + 7 FADH2 + 7 NADH + 7 H+


Summary of atp production via lipid oxidation
Summary of ATP Production sarcoplasmic reticulum of contracting musclevia Lipid Oxidation

ATP Balance Sheet for Palmitic Acid (16 carbon) ATP

  • Activation of FA chain -1

  • ß oxidation (16 Carbons / 2) –1 = 7 (at 5 ATP each) 35

  • Acetyl-CoA (16 Carbons / 2) = 8 (at 12 ATP each) 96

    Total per chain 130


Electrochemical energy and atp synthesis
Electrochemical Energy and ATP Synthesis sarcoplasmic reticulum of contracting muscle


Energy for burst and endurance activities
Energy for “Burst” and Endurance Activities sarcoplasmic reticulum of contracting muscle

  • Rate of ATP Production (M of ATP/min)

  • phosphagen system ..............4

  • anaerobic glycolysis..………2.5

  • aerobic system.......................1

How long Can it Last?

  • phosphagen system...8 to 10 sec

  • anaerobic glycolysis…1.3 to 1.6 min

  • aerobic system.........unlimited time(as long as nutrients last)


Aerobic energy
Aerobic Energy sarcoplasmic reticulum of contracting muscle

  • During low intensity exercise, the majority of energy is provided aerobically

  • Energy produced aerobically requires O2

  • Therefore, O2 uptake can be used as a measure for energy use


Exercise physiology mpb 326

Exercise Testing in Health and Disease sarcoplasmic reticulum of contracting muscle


Oxygen uptake and exercise domains

I sarcoplasmic reticulum of contracting muscle

N

C

R

E

M

E

N

T

A

L

4

VO2 (l/min)

Severe

2

Heavy

Moderate

0

150

300

Work Rate (Watts)

Oxygen Uptake and Exercise Domains


Anaerobic threshold concept

Heart sarcoplasmic reticulum of contracting muscle

Disease

Onset of lactic acidosis

Athlete

Anaerobic Threshold Concept

Exercise

15

Blood

Lactate

mM

10

5

0

150

50

100

200

250

Rest Period

Exercise

(watts)


Anaerobic threshold in some elite long distance athletes can be close to max

Bill sarcoplasmic reticulum of contracting muscle

Rodgers

Anaerobic Threshold in Some Elite Long Distance Athletes can be close to Max

Exercise

15

Onset of lactic

acidosis

Blood

Lactate

mM

10

5

0

60

20

40

Basal

Oxygen

Uptake

80

100

Oxygen Uptake

(% maximum)


Oxygen deficit and debt
Oxygen Deficit and Debt sarcoplasmic reticulum of contracting muscle


Oxygen uptake and exercise domains1
Oxygen Uptake and sarcoplasmic reticulum of contracting muscleExercise Domains

C

O

N

S

T

A

N

T

L

O

A

D

Severe

4

Heavy

2

Moderate

0

12

24

Time (minutes)


Lactate and exercise
Lactate and Exercise sarcoplasmic reticulum of contracting muscle

12

Blood Lactate

mM

6

0

12

24

0

Time (minutes)


Three principles of fuel utilization during exercise
Three Principles of Fuel Utilization during Exercise sarcoplasmic reticulum of contracting muscle

  • Maintaining glucose homeostasis

  • Using the fuel that is most efficient

    Storage

    Metabolic

  • Preserving muscle glycogen core


Glucose homeostasis is usually maintained despite increased glucose uptake by the working muscle
Glucose homeostasis is usually maintained despite increased glucose uptake by the working muscle

Moderate

Exercise

1

0

0

8

0

Blood

6

0

Glucose

(

mg

/

dl

)

4

0

2

0

0

5

4

R

a

t

e

s

o

f

G

l

u

c

o

s

e

E

n

t

r

y

a

n

d

E

n

t

r

y

3

R

e

m

o

v

a

l

f

r

o

m

t

h

e

B

l

o

o

d

2

R

e

m

o

v

a

l

-

1

-

1

(

m

g

k

g

m

i

n

)

1

0

-

3

0

0

3

0

6

0

T

i

m

e

(

m

i

n

)


Carbohydrate stores after an overnight fast sedentary
Carbohydrate Stores after an Overnight Fast glucose uptake by the working muscleSedentary

100

grams

Liver

Glycogen

Blood

Glucose

Muscle

Glycogen

400

grams

4 grams


Carbohydrate stores after an overnight fast 1 hr of exercise
Carbohydrate Stores after an Overnight Fast glucose uptake by the working muscle1 hr of Exercise

Liver

Glycogen

Blood

Glucose

Muscle

Glycogen

400

grams

4 grams

100

grams


Carbohydrate stores after an overnight fast 2 hr of exercise
Carbohydrate Stores after an Overnight Fast glucose uptake by the working muscle2 hr of Exercise

Liver

Glycogen

Blood

Glucose

Muscle

Glycogen

400

grams

4 grams

100

grams


Carbohydrate stores after an overnight fast 3 hr of exercise
Carbohydrate Stores after an Overnight Fast glucose uptake by the working muscle3 hr of Exercise

Liver

Glycogen

Blood

Glucose

Muscle

Glycogen

400

grams

4 grams

100

grams


Carbohydrate stores after an overnight fast 4 hr of exercise
Carbohydrate Stores after an Overnight Fast glucose uptake by the working muscle4 hr of Exercise

Liver

Glycogen

Blood

Glucose

Muscle

Glycogen

400

grams

4 grams

100

grams

!!!


Contribution of different fuels to metabolism by the working muscle is determined by 3 objectives
Contribution of different fuels to metabolism by the working muscle is determined by 3 objectives:

  • Maintaining glucose homeostasis

  • Using the fuel that is most efficient

    Storage

    Metabolic

  • Preserving muscle glycogen core


The most efficient fuel depends on exercise intensity and duration
The Most Efficient Fuel depends on muscle is determined by 3 objectives:Exercise Intensity and Duration

Metabolic Efficiency

CHO is preferred during high intensity exercise because its metabolism yields more energy per liter of O2than fatmetabolism.

kcal/l of O2

CHO 5.05

Fat 4.74

CHO can also produce energy without O2!!!

Storage Efficiency

Fat is preferred during prolonged exercise because its metabolism provides more energy per unit mass than CHO metabolism.

kcal/g of fuel

CHO 4.10

Fat 9.45

Fats are stored in the absence of H2O.


Effects of exercise intensity
Effects of Exercise Intensity muscle is determined by 3 objectives:

  • Plasma FFA (fat from fat cells) is the primary fuel source for low intensity exercise

  • As intensity increases, the source shifts to muscle glycogen

From: Powers & Howley. (2007). Exercise Physiology. McGraw-Hill.


Effects of exercise duration
Effects of Exercise Duration muscle is determined by 3 objectives:

From: Powers & Howley. (2007). Exercise Physiology. McGraw-Hill.


Fuel selection
Fuel Selection muscle is determined by 3 objectives:

  • As intensity increases carbohydrate use increases, fat use decreases

  • As duration increase, fat use increases, carb use decreases

From: Powers & Howley. (2007). Exercise Physiology. McGraw-Hill.


Contribution of different fuels to metabolism by the working muscle is determined by 3 objectives1
Contribution of different fuels to metabolism by the working muscle is determined by 3 objectives:

  • Maintaining glucose homeostasis

  • Using the fuel that is most efficient

    Storage

    Metabolic

  • Preserving muscle glycogen core


Exercise physiology mpb 326
Other fuels are utilized to spare muscle glycogen during prolonged exercise thereby delaying exhaustion

Adipose

Lactate

NEFA

Pyruvate

Glycerol

Amino Acids

Muscle

NEFA

GLY

ATP

GNG

GLY

Glucose

Liver

As exercise duration increases:

• More energy is derived from fats and less from glycogen.

• Amino acid, glycerol, lactate and pyruvate carbons are

recycled into glucose.


Contribution of different fuels to metabolism by the working muscle is determined by 3 objectives2
Contribution of different fuels to metabolism by the working muscle is determined by 3 objectives:

  • Maintaining glucose homeostasis

  • Using the fuel that is most efficient

    Storage

    Metabolic

  • Preserving muscle glycogen core


Discussion question
Discussion Question muscle is determined by 3 objectives:

Can you accommodate all three principles of fuel utilization?

Why not?

What is the Consequence?