Chapter 4 - Exercise Metabolism

Question 1

Oxygen Deficit

Answer 1

Amount of oxygen needed but did not have.
-lack of oxygen uptake is usually at the beginning of exercise. (this can also occur when there is an increase in intensity.)

Question 2

Oxygen debt

Answer 2

Term used by A.V. Hill

• repayment for O2 deficit at onset of exercise.
• term used interchangeably with EPOC

Question 3

Excess Post Exercise Oxygen Consumption (EPOC)

Answer 3

Reflects that only -20% of elevated O2 consumption is used to “repay” O2 deficit - thus other factors
-term used interchangeably with oxygen debt (Professor likes this term)

Question 4

Rapid Portion of O2 debt

Answer 4

• Resynthesis of stored PC + ATP
• Replenishing muscle and blood O2 stores
• Rapid phase of lactate removal (some lactate NOT ALL.)

Question 5

Slow Portion of O2 debt

Answer 5

• Elevated heart rate and breathing = increased metabolic need
• elevated body temperature = increased metabolic rate
• elevated EPI and NE= increased metabolic rate
• conversion of lactic acid to glucose (gluconeogensis)

Question 6

EPOC (O2 debt) is greater following higher intensity exercise for these reasons….

Answer 6

• higher body temp. (slow)
• greater depletion of PC + ATP (fast)
• greater blood concentration of lactic acid (fast)
• higher levels of blood epi and norepinephrine
• thus greater HR and breathing (slow)
• need to decrease (lactate, hormones, temp) and replenish ATP/PC stores and O2.

Question 7

Physiological Factors influencing VO2 max

Answer 7

• maximum ability of CV system to deliver O2 to the muscle.
• ability of muscles to use O2 and produce ATP aerobically
• Endurance training can increase VO2 max.

Question 8

LDH Isoforms

Answer 8

forms of an enzyme that either goes to pyruvate or lactic acid.
-has 5 isoforms

Question 9

In low intensity exercises what is the primary source of fuel?

Answer 9

Fats (Lipids)

Question 10

Mechanisms to explain the lactate threshold.

Answer 10

• low muscle oxygen
• accelerated glycolysis
• recruitment of fast twitch fibers
• reduced rate of lactate removal

Question 11

Practical Uses of the Lactate Threshold

Answer 11

• Prediction of performance (combined with VO2 max)

- Planning training programs (marker of training intensity, choose a training HR based on LT)

Question 12

Estimation of Fuel Utilization During Exercise

- Respiratory Exchange Ratio (RER or R)*

Answer 12

one of the methods to estimate fuel utilization during exercise. R = VCO2/VO2

Question 13

Estimation of Fuel Utilization During Exercise

-R for Fat (palmitic acid)

Answer 13

one of the methods to estimate fuel utilization during exercise. R = VCO2/VO2 = 16 CO2/ 23 O2 = 0.70

Question 14

R for Carbohydrate (glucose)

Answer 14

one of the methods to estimate fuel utilization during exercise. R = VCO2/VO2 = 6 CO2/6 O2 = 1.0

Question 15

Fats

Answer 15

What is the primary fuel for low intensity exercise (<30% VO2 max)

Question 16

Carbohydrates

Answer 16

What is the primary fuel for high intensity exercise (>70% VO2 max)

Question 17

Muscle Glycogen

Answer 17

• primary source of carbohydrate during high intensity exercise
• supplies much of the carbohydrate in the first hour of exercise
• limited amount of storage within the muscle of glycogen

Question 18

Sources of Protein During Exercise

Answer 18

Ezymes tht degrade protein (proteases) are activated in long-term exercise.

Question 19

Lactate as a Fuel Source During Exercise

Answer 19

• can be used as a fuel source by skeletal muscle and the heart. (converted to acetyl - CoA and enters Krebs cycle)
• Can be converted to glucose in the liver (Cori Cycle)
• Lactate Shuttle (lactate produced in one tissue and transported to another.)

Question 20

The Cori Cycle : Lactate as a Fuel Source

Answer 20

• Lactate (some) produced by skeletal muscle is transported to the liver
• liver converts lactate to glucose (gluconeogenesis)
• glucose is transported back to muscle and used as fuel.

Question 21

Approximately what percent of ATP is produced by aerobic metabolism>

Answer 21

Almost 100 %

Question 22

Who is known for the term oxygen debt (repayment for O2 deficit at onset of exercise)?

Answer 22

A.V. Hill

Question 23

What is anaerobic energy system is the fasted thing used and fastest thing replenished?

Answer 23

Phosphocreatine + ATP

Question 24

Is lactic acid removed more rapidly with no exercise or light exercise in recovery?

Answer 24

Light exercise

Question 25

In the first 1-5 seconds of exercise what anaerobic system is utilized to supply ATP?

Answer 25

ATP-Phosphocreatine system

Question 26

Intense exercise lasting longer than 5 seconds activated what anaerobic system to supply ATP?

Answer 26

Glycolysis

Question 27

Exercise lasting longer than 45 seconds utilized what system in order to supply the body’s demand for ATP?

Answer 27

A mixture of of ATP-PC system, glycolysis, and aerobic pathways. The longer the activity the more aerobic the metabolism becomes and less anaerobic.

Question 28

The production of ________ is the cause of muscle fatigue not lactic acid.

Answer 28

Hydrogen Ions

Question 29

When a steady state of O2 usage is reached less _______is used and more _______ are used.

Answer 29

Carbs (sugars) : Lipids (Fats)

Question 30

What type of physical training can increase VO2 max?

Answer 30

endurance

Question 31

What type of muscle twitch fibers have more heart type LDH isoforms and thus produce less lactate?

Answer 31

Slow Twitch Fibers

Question 32

In high intensity exercises what is the primary source of fuel?

Answer 32

Carbohydrates

Question 33

What is the crossover concept?

Answer 33

The description of the shift from Fat to Carbohydrates metabolism as exercise intensity increases.
- this is due to the recruitment of more fast-twitch muscle fibers and increasing blood levels of EPI.