Lecture 20 - Integration II

Question 1

What are the necessary factors in oxidative phosphorylation?

Answer 1

Oxygen consumption and carbon dioxide production are necessary factors in oxidative phosphorylation.

Question 2

What is the Respiratory Exchange Ratio (RER)?

Answer 2

Ratio between oxygen consumption and CO2 production
RER= VCO2/VO2

Question 3

Why is more oxygen needed for fat than glucose during metabolism?

Answer 3

More oxygen is needed proportional to amount of carbon, so more oxygen needed for fat than glucose.

Question 4

What does the amount of oxygen used during metabolism depend on?

Answer 4

The amount of oxygen used during metabolism depends on the type of fuel being oxidized.

Question 5

What can RER inform us?

Answer 5

What type of fuel is being oxidized.
if close to 1, glucose is the major fuel source or if less than 1.0, fats are the major fuel source

Question 6

When is anaerobic production of ATP utilised?

Answer 6

For when we do not have enough time to utilise aerobic production of ATP - quick sprints or explosive efforts

Question 7

What is anaerobic ATP production?

Answer 7

Anaerobic - producing ATP with absence of oxygen

Question 8

Where do we get ATP from (no oxygen)?

Answer 8

We get ATP from fuel stores of creatine phosphate and glycogen

Question 9

When is ATP GENERATION Phosphocreatine pathway used?

Answer 9

During anaerobic exercise - no O2 in pathway
~3-15 secs maximal exercise

Question 10

What is the ATP GENERATION Phosphocreatine pathway?

Answer 10

When ATP is used by ATPase,
the ADP and Pi can be recycled to make more ATP from PCr
PCr can recycle ATP during
exercise until used up.
• Yields 1 ATP for each PCr
• ~3-15 secs maximal exercise

Question 11

Where are our phosphocreatine stores?

Answer 11

In musculoskeletal cells

Question 12

When is ATP GENERATION Glycolysis pathway used?

Answer 12

Anaerobic- no oxygen required
~15s to 2 mins

Question 13

What is the ATP GENERATION Glycolysis pathway?

Answer 13

Glucose is converted to pyruvate which generates 2 ATP

Question 14

What are our sources of ATP generation

Answer 14

Phosphocreatine
Glycolysis
Oxidative (from either CHS or fats)

Question 15

Describe protein as a fuel source

Answer 15

Rarely used as a substrate
• starvation
• can be converted to glucose
(gluconeogenesis)
• can be converted to acetyl-CoA
Energy yield not easy to determine
2-5% of fuel source

Question 16

At lower speeds, what is utilised for energy production?

Answer 16

At lower speeds both trained and untrained - utilise fats for ATP production

Question 17

What is utilised for ATP production as excerise intensity increase?

Answer 17

Fats change to carbohydrate and anaerobic pathways

Question 18

How does the utilisation of ATP production during exercise in trained people compare to that of untrained people?

Answer 18

As intensity increases, trained person can increase utilising only fats up until a much higher speed (change to carbohydrate and anaerobic pathways much higher speeds)

Question 19

Besides VO2max, what is another important parameter for athlete’s?

Answer 19

Threshold intensity (aka lactate threshold, functional threshold power, FTP)

Question 20

What is threshold intensity?

Answer 20

Maximal intensity that can be sustained for a prolonged period

Question 21

What defines threshold intensity?

Answer 21

The threshold intensity or lactate threshold is defined as the point at which blood lactate begins to substantially accumulate above resting concentrations during exercise of increasing intensity (aka as glycolysis or anaerobic production of ATP begins to dominate).

Question 22

In trained athletes, what can lactic acid as a fuel source be used for?

Answer 22

Trained athlete can use lactic acid as a fuel source for the brain, liver, and skeletal muscle.

Question 23

What is lactate threshold?

Answer 23

Lactate threshold is balance between anaerobic glycolysis and clearance of lactate.
At exercise speed increases, and power output increases, there is a point where blood lactate first appears to increase disproportionally above resting values

Question 24

How can lactate threshold increase over time?

Answer 24

Training between aerobic and lactate threshold is trains the body to use that lactic acid and to increase enzymes to break it down (so it can’t accumulate as fast) - this will increase lactate threshold overtime

Question 25

What happens when we pass the lactate threshold?

Answer 25

When we pass the lactate threshold, there will also be a exponential increase in VE and VCO2. Lactic acid gets buffered by bicarbonate (increase H+ and CO2) which stimulates increase in VE and VCO2
VCO2 more than VO2 since switching to anaerobic.
Heart rate linear - increase heartrate, increase intensity

Question 26

What is lactate threshold expressed as?

Answer 26

Expressed as a % of maximal oxygen
uptake (%VO2max).

Question 27

What does lactate threshold represent?

Answer 27

Represents the fastest pace that can be tolerated during a long term endurance event. Perform at higher %VO2max reflects a higher lactate threshold.

Question 28

What is Post-exercise oxygen consumption (EPOC)?

Answer 28

The oxygen uptake needed to balance the oxygen debt created after exercise

Question 29

Why do we have EPOC?

Answer 29

When exercise begins, the oxygen transport system does not immediately supply the needed quantities of oxygen to the active muscles.
It takes several minutes to reach the required level at which aerobic processes are fully functional.

Question 30

Why does it take several minutes after exercise for oxygen consumption to reach rest levels?

Answer 30

Because it takes a while to oxygen to catch up to required level.

Question 31

Why is oxygen needed post exercise?

Answer 31

Oxygen is needed to restore ATP and PCr levels but also to combust the lactate.

Question 32

How is cardiac output determined? (equation)

Answer 32

Q = HR x SV

Question 33

What is avg cardiac output at rest?

Answer 33

Resting CO=5L/min

Question 34

What is avg cardiac output during exercise for trained and untrained?

Answer 34

Untrained CO=20L/min
Trained CO=40L/min

Question 35

What is the relationship between HR and increasing exercise intensity?

Answer 35

As intensity of exercise increases, HR increases proportionately.

Question 36

How do we measure HR?

Answer 36

Pulse

Question 37

What is maximum HR?

Answer 37

The maximum HR is the highest HR value
achieved in an all-out effect to the point of
volitional fatigue.
HRmax is a highly reliable value that remains constant day to day.
Decreases each year with gradual decline with age.

Question 38

How can we estimate HR based off age?

Answer 38

A more accurate equation to estimate HR from
age is:
HRmax= 208- (0.7 X age).

Question 39

What is steady-state HR?

Answer 39

When exercise is held constant at any submaximal workload, HR increases rapidly but then reaches a plateau. The plateau is steady-state. This HR is what is needed to provide the oxygenated blood to the muscle bed for the level of activity of the muscle.
• If intensity increases, so does steady-state HR
• Adjustment to new intensity takes 2 to 3 min, however as the intensity gets stronger, it takes longer.

Question 40

Why can there be a difference in HR between two people doing the same level of work?

Answer 40

The individual with better endurance capacity because can extract more oxygen (e.g. more mitochondria in muscles) and so does not have to increase HR to the same level of intensity

Question 41

Why is HR the bigger variable in cardiac output (Q)?

Answer 41

Because HR can continual increase whilst SV reaches a max and then stays constant (can’t increase further)