Exercise Metabolism W2

Question 1

How do you measure respiratory exchange ratio?

Answer 1

VCO2/ VO2

Question 2

When estimating fuel utilisation, when do measurements need to be performed in order to be reflective of gases in tissues?

Answer 2

Steady-state exercise

Question 3

How much protein is estimated to be used as fuel during exercise?

Answer 3

0

Question 4

What is the caloric equivalent for oxygen when only fat is used?

Answer 4

4.69Kcal per L

Question 5

What is the caloric equivalent for oxygen when only carbohydrate is used?

Answer 5

5.05Kcal per L

Question 6

What is the crossover concept?

Answer 6

The shift from fat to CHO metabolism as a result of increased exercise intensity

Question 7

What causes the crossover concept?

Answer 7

Recruitment of fast muscle fibres

Increasing blood levels of epinephrine to stimulate glycolysis and lactate production

Question 8

What does increasing blood levels of epinephrine
to stimulate glycolysis and lactate production do?

Answer 8

Inhibits fat metabolism by reducing the availability of fat as a substate

Question 9

What factors govern fuel selection during exercise?

Answer 9

Intensity
Duration

Question 10

How does exercise duration effect fuel utilisation during exercise?

Answer 10

A longer duration increases the rate of lipolysis

Question 11

What is beta-oxidation?

Answer 11

Process of oxidising fatty acids to Acetyl-CoA

Question 12

What does glycogen depletion cause?

Answer 12

Decreased glycolysis
Decreased Pyruvate Production
Decreased Krebs-Cycle activity

Question 13

What is FATmax?

Answer 13

Highest rate of fat oxidation
Reached just before lactate threshold

Question 14

What is an increased rate of glycogenolysis caused by?

Answer 14

Recruitment of fast-twitch fibres
Elevated blood epinephrine levels

Question 15

Where does the lactate threshold typically appear in untrained individual?

Answer 15

50-60% VO2max

Question 16

What is OBLA?

Answer 16

Onset of Blood Lactate Accumulation
Point at which blood lactate reaches >4 mmol/L

Question 17

What are the possible explanations of an individuals lactate threshold?

Answer 17

Accelerated Glycolysis
Reduced rate of lactate removal from the blood
Recruitment of fast-twitch muscle fibres during intense, rapid exercise

Question 18

How does accelerated glycolysis caused a lactate threshold?

Answer 18

NADH is produced faster than it is shuttled into the mitochondria= failure to keep up with glycolysis results in pyruvate accepting un-shuttled H+= formation of lactate

Question 19

How does recruitment of fast-twitch muscle fibres during intense, rapid exercise cause a lactate threshold?

Answer 19

LDH isozyme (exact form of the enzyme) in fast fibres has a greater affinity for attaching to pyruvate= promotes lactate formation

Question 20

How does reduced rate of lactate removal from the blood cause a lactate threshold?

Answer 20

Blood flow to muscle prioritized over tissues responsible (liver) for removing lactate

Question 21

How do you work out blood lactate concentration?

Answer 21

Lactate entry into the blood- blood lactate removal

Question 22

What are each mechanism contributing to lactate threshold independent too?

Answer 22

Whether there is sufficient oxygen

Question 23

What causes delayed onset muscle soreness?

Answer 23

Likely microscopic injury to muscle fibres

Question 24

What does microscopic injury do to fibres?

Answer 24

Causes a slow cascade of biochemical events which leads to inflammation and edema within the injured muscle