LESSON 14 - exercise thresholds

Question 1

what dose increasing lactate mean for protons ?

Answer 1

increasing protons

Question 2

does increased lactate have an acidifying or basic effect

Answer 2

acidifying (increased protons (H+) = decreased pH)

Question 3

what is buffering protons ?

Answer 3

neutralizing (keep us at that level)

Question 4

what does bicarbonate do ?

Answer 4

compensate for that acidity

Question 5

when bicarbonate combines with H what does it form ?

Answer 5

water and carbon dioxide

Question 6

H + HCO3 produces H2O + CO2 uses what anhydrase ?

Answer 6

carbonic anhydrase

Question 7

what keeps CO2 from accumulating and drives the carbonic anhydrase reactions towards production of CO2 and “consumption” of H+ ?

Answer 7

ventilation

Question 8

what are the two metabolic boundaries ?

Answer 8

• lactate threshold (LT)
• critical intensity (CI) or maximal metabolic steady-state

Question 9

describe lactate threshold :

Answer 9

the metabolic rate (or VO2) at which blood lactate cannot be maintained at resting levels

Question 10

what types of intensity is lactate threshold ?

Answer 10

separates moderate from heavy intensity exercise domains

Question 11

describe critical intensity or maximal metabolic steady-state :

Answer 11

• the highest VO2 at which a heightened lactate production in muscle may be stabilized in blood

Question 12

what types of intensity is critical intensity ?

Answer 12

separates heavy from severe intensity exercise domains

Question 13

how can we detect these boundary crossings through incremental exercise ?

Answer 13

by measuring gas exchange and ventilation at the mouth

Question 14

dissociating bicarbonate makes what ?

Answer 14

CO2 & H2O

Question 15

for every O2 we produce about the same rate amount of what …

Answer 15

CO2

Question 16

if we have no change in lactate (pH remains stable) what does this mean for bicarbonate ?

Answer 16

no bicarbonate since no buffering is needed

Question 17

is lactate and pyruvate a reversible equation ?

Answer 17

yes !

Question 18

what is used to convert pyruvate to Lactate ?

Answer 18

lactate dehydrogenase

Question 19

at a low production, describe lactate appearance …

Answer 19

rate of lactate appearance equals disappearance

Question 20

below the lactate threshold (moderate) is hyperpnea or hyperventilation ?

Answer 20

hyperpnea (healthy amount)

Question 21

do we want a lot of lactate ?

Answer 21

• no we do not
• we want a low concentration in cytosol to maintain equilibrium

Question 22

where is lactate produced ?

Answer 22

in the muscle

Question 23

what is lactate associated with ?

Answer 23

with an increase in H+ ions

Question 24

above all else what is most important to maintain ?

Answer 24

H+ (bicarbonate plays a role in this)

Question 25

we don’t want too much pyruvate, but why do we need pyruvate ?

Answer 25

to support ATP rate demand

Question 26

what does stopping pyruvate inhibit ?

Answer 26

glycolysis (dont want that)

Question 27

when is steady state achieved ?

Answer 27

when lactate is stable

Question 28

what organ replenishes bicarbonate ?

Answer 28

kidneys

Question 29

moderate and heavy states are both examples of hyperpnea or hyperventilation ?

Answer 29

hyperpnea

Question 30

what does it mean when lactate is elevates and unstable ?

Answer 30

• high production
• rate of lactate appearance exceeds clearance

Question 31

severe states is hyperpnea or hyperventilation ?

Answer 31

hyperventilation

Question 32

what are the two metabolic thresholds ?

Answer 32

GET/VT1 and RCP/VT2

Question 33

describe GET/VT1:

Answer 33

• the VO2 at the onset of bicarbonate buffering where VCO2 and VE begin to increase at a greater rate than VO2
• ≈ LT

Question 34

what does GET/VT1 seperate ?

Answer 34

moderate from heavy intensity exercise domains

Question 35

describe RCP/VT2 :

Answer 35

• the VO2 at which bicarbonate buffering cannot prevent acidosis and hyperventilation ensues to compensate
• ≈ CI

Question 36

what does RCP/VT2 separate ?

Answer 36

heavy from severe intensity exercise domains

Question 37

is GET/VT1 hyperpnea or hyperventilation ?

Answer 37

hyperpnea

Question 38

is RCP/VT2 hyperpnea or hyperventilation ?

Answer 38

hyperventilation

Question 39

what does GET stand for ?

Answer 39

gas exchange threshold

Question 40

what does RCP stand for ?

Answer 40

respiratory compensation point

Question 41

describe the RCP performance two mile case performance :

Answer 41

• those with higher RCP had a better two mile rate
• can be used to prove that better RCP = better performance