Metabolic Response to exercise

Question 1

almost 100% of ATP is produced by what type of metabolism

Answer 1

aerobic

Question 2

what is the resting O2 consumption

Answer 2

.25L/min

Question 3

what 2 things increase rapidly when you go from rest to exercise transitions

Answer 3

ATP production and Oxygen uptake

Question 4

how long does it take to reach a steady state when you begin to exercise

Answer 4

1-4 minutes

Question 5

define oxygen deficit

Answer 5

lag in oxygen uptake at the beginning of exercise

Question 6

compare the oxygen deficit in trained and untrained subjects

Answer 6

1. Trained: have a lower oxygen deficit
   - their aerobic bioenergetic capacity is better
   - results in less production of lactate and H+
2. untrained: have higher levels of oxygen deficit

Question 7

define steady state

Answer 7

when your ventilation levels off

Question 8

define oxygen debt

Answer 8

term used to describe recovery from exercise

-repayment for O2 deficit at onset of exercise

Question 9

what does EPOC stand for and what is it used to describe

Answer 9

excess post-exercise oxygen consumption

-repayment for O2 deficit at onset of exercise

Question 10

what is involved in the rapid portion of O2 debt

Answer 10

1. resynthesis of stored PC

2. replenishing of muscle and blood O2 stores

Question 11

what is involved in the slow portion of O2 debt

Answer 11

1. elevated heart rate and breathing=energy need
2. elevated body temp=metabolic rate
3. elevated epinephrine and norepinephrine metabolic rate
4. conversion of lactic acid to glucose

Question 12

do you ever reach a steady state during intense exercise?

Answer 12

no because your heart rate cant catch up to the ventilation

Question 13

when is EPOC the greatest

Answer 13

following higher intensity exercise

Question 14

what does increase heat during exercise do

Answer 14

it lowers the affinity between oxygen and hemoglobin

Question 15

define the anaerobic threshold

Answer 15

lactate levels increase

Question 16

what was the classical theory regarding the removal of lactic acid following exercise

Answer 16

majority of lactic acid is converted to glucose in the liver

Question 17

what is the more recent evidence regarding the removal of lactic acid following exercise

Answer 17

70% of lactic acid is oxidized and used as a substrate by the heart and skeletal muscle
20% is converted to glucose
10% is converted to amino acids

Question 18

when is lactic acid removed more rapidly

Answer 18

during light exercise

-optimal intensity is 30-40$ VO2 max

Question 19

what are the metabolic responses to short term intense exercise

Answer 19

1. First 1-5 seconds, ATP through ATP-PC system is used
2. longer than 5 seconds: glycolysis
3. longer than 45 seconds: ATP production through aTP-PC, glycolysis, and aerobic systems

at 60 seconds 70% anaerobic
at 2 minutes 50% anaerobic

Question 20

what are the metabolic responses to prolonged exercise

Answer 20

1. exercise lasting longer that 10 minutes
   - aerobic metabolism
   - steady state oxygen uptake can generally be maintained during submaximal exercise
2. in a hot/humid environment or high intensity
   - upward drift in oxygen uptake over time due to increased body temp and epinephrine and norepinephrine

Question 21

how long does oxygen uptake continue to increase

Answer 21

increases linearly until VO2 max is reached which means that even if you continue to increase the work rate, you cannot increase you O@ intake

Question 22

how is VO2 max affected

Answer 22

by genetics and training

Question 23

what are 2 physiological factors influencing VO2 max

Answer 23

1. max ability of cardiorespiratory system to deliver oxygen to the muscle
2. ability of muscles to use oxygen and produce ATP aerobically

Question 24

what are four things that explain the lactate threshold

Answer 24

1. low muscle oxygen
2. accelerated glycolysis
3. recruitment of fast-twitch fibers
4. reduced rate of lactate removal

you want to train above threshold in order to improve

Question 25

what are practical uses of the lactate threshold

Answer 25

1. prediction of performance combined with VO2 max 2. planning training programs - choose training HR based on LT

Question 26

does lactate cause muscle soreness

Answer 26

no, soreness is due to delayed onset muscle soreness

Question 27

during low intensity exercise (<30$ VO2 max) what is the primary fuel being used

Answer 27

fats

Question 28

during high intensity exercise (>70% VO2 max) what is the primary fuel being used

Answer 28

carbohydrates

Question 29

what is the crossover concept

Answer 29

describes the shift from fat to CHO metabolism as exercise intensity increases due to the recruitment of fast muscle fibers and increasing blood levels of epinephrine

Question 30

is low intensity best for burning fat?

Answer 30

no, the total fat oxidation is low | -during more intense exercise total fat oxidation is higher and total energy expended is higher

Question 31

What is the fuel selection during prolonged low intensity exercise

Answer 31

-it is a shift from carb to fat metabolism dur to an increased rate of lipolysis (breakdown of triglycerides into glycerol and FFA -stimulated by rising blood levels of epinephrine

Question 32

muscle glycogen

Answer 32

1. primary source of carbs during high intensity exercise | 2. supplies much of the carbs in the first hour of exercise

Question 33

blood glucose

Answer 33

from liver glycogenolysis - primary source of carbs during low intensity exercise - important during long duration exercise as muscle glycogen levels decline

Question 34

what are 3 branched chain amino acids

Answer 34

leucine isoleucine valine

Question 35

what are 2 sources of fat during exercise

Answer 35

1. intramuscular triglycerides | 2. plasma FFA

Question 36

intramuscular triglycerides

Answer 36

primary source of fat during higher intensity exercise

Question 37

plasma FFA

Answer 37

- from adipose tissue lipolysis - FFA converted to acetyl-CoA and enters krebs cycle - primary source of fat during LOW intensity exercise - becomes more important as muscle triglyceride levels decline in long duration exercise

Question 38

sources of protein during exercise

Answer 38

proteins broken down into amino acids - muscle can directly metabolize branch chain amino acids and alanine - liver can convert alanine to glucose

Question 39

what is the enzyme that degrades proteins

Answer 39

proteases

Question 40

describe lactate as a fuel source

Answer 40

1. can be used as a fuel source by skeletal muscle and the heart - it is converted to acetly-CoA and enters the krebs cycle 2. can be converted to glucose in the liver(cori cycle) 3. lactate shuttle - lactate produced in one tissue and transported to another