Chapter 4 Flashcards
0
Q
energy requirements at rest: _____ levels are low
A
blood lactate
1
Q
almost _____ of ATP is produced by ________ metabolism
A
100%
aerobic
2
Q
resting oxygen consumption - ______ L/min (energy requirements at rest)
A
0.25
3
Q
resting oxygen consumption - ______ mL/kg/min (energy requirements at rest)
A
3.5
4
Q
if lactate levels are high, you are producing a lot of ATP _______
A
anaerobically
5
Q
smaller people will have a _____ resting oxygen consumption
A
lower
6
Q
bigger people will have a ______ resting oxygen consumption
A
higher
7
Q
if you have a low thyroid hormone, metabolism will _______
A
turn down = low metabolism
8
Q
rest-to-exercise transitions: ATP production ____ immediately
A
increases
9
Q
rest-to-exercise transitions: oxygen uptake ______ rapidly
A
increases
10
Q
oxygen uptake reaches steady state within _______ minutes
A
1-4
11
Q
after steady state is reached, ATP requirement is met through ________ ATP production
A
aerobic
12
Q
initial ATP production through anaerobic pathways
A
ATP-PC system
glycolysis
13
Q
oxygen deficit
A
lag in oxygen uptake at beginning of exercise
- if you run as fast as you can, you wont reach steady state; you will just get closer to your maximum
14
Q
you start producing ATP almost immediately upon ________
A
movement
15
Q
if you take off in a walk - produce some ATP _____
A
aerobically
16
Q
if you take off in a run - produce ATP _______
A
anaerobically
17
Q
O2 deficit is related to the amount of ATP you produced ________
A
anaerobically
18
Q
comparison of trained and untrained subjects
A
trained subjects have a lower O2 deficit
- results in less production of lactate and H+
19
Q
recovery from exercise: oxygen debt
A
- term used by A.V. Hill
- repayment for O2 deficit at onset of exercise
20
Q
oxygen uptake remains _____ above rest into recovery
A
elevated
21
Q
Excess Post-exercise Oxygen Consumption (EPOC)
A
terminology reflects that only ~20% elevated O2 consumption used to “repay” O2 deficit
22
Q
a more fit person will have a _______ EPOC
A
lower - recover faster
23
Q
more fit you are, the _____ the heart rate after exercise
A
lower
ex. step test
24
EPOC is ________ following higher intensity exercise
greater
25
removal of lactic acid following exercise: classical theory
majority of lactic acid converted to glucose in liver
26
removal of lactic acid following exercise: recent evidence
- 70% of lactic acid is oxidized
- used as a substrate by heart and skeletal muscle
- 20% converted to glucose
- 10% converted to amino acids
27
lactic acid is removed more _______ with light exercise in recovery
rapidly
28
lactic acid is produced in _______
muscle
29
the _____ loves lactic acid as fuel (will oxidize lactate)
heart
30
a light cool down helps with ______ and ________
recovery and oxygen debt
31
first 1-5 seconds of exercise
ATP through ATP-PC system
32
intense exercise longer than 5 seconds
shift to ATP production via glycolysis
33
events lasting longer than 45 seconds (metabolic responses to short-term, intense exercise)
ATP production through ATP-PC system, glycolysis, and aerobic systems
34
events lasting longer than 45 seconds: anaerobic vs. aerobic at 60 seconds
70% anaerobic/30% aerobic
35
events lasting longer than 45 seconds - anaerobic/aerobic ratio at 2 minutes
50% anaerobic/50% aerobic
36
metabolic responses to prolonged exercise: prolonged exercise (> 10 minutes)
ATP production primarily from aerobic metabolism
| - steady state O2 uptake can generally be maintained during submaximal exercise
37
metabolic responses to prolonged exercise - prolonged exercise in a hot/humid environment or at high intensity
upward drift in O2 uptake over time
| - due to body temperature and rising epinephrine and norepinephrine
38
steady-state
you can produce ATP at the same rate you are using it
39
someone who is more fit will be able to run _______ at steady state
faster
40
metabolic responses to incremental exercise: oxygen uptake ______ lineraly until maximal oxygen uptake is reached
increase
41
VO2 max
"physiological ceiling" for delivery of O2 to muscle
| - affected by genetics and training
42
physiological factors influencing VO2 max
maximum ability of cardiorespiratory system to deliver oxygen to the muscle
- ability of muscles to use O2 and produce ATP aerobically
43
lactate threshold
the point at which blood lactic acid rises systematically during incremental exercise
44
lactate threshold: appears at __________ VO2 max in untrained subjects
!50% - 60%
45
lactate threshold: at higher work rates, VO2 max is _________ in trained subjects
65%-80%
46
lactate threshold: also called ......
anaerobic threshold
| onset of blood lactate accumulation (OBLA) - blood lactate levels reach 4 mmol/L
47
OBLA
onset of blood lactate accumulation
| - blood lactate levels reach 4 mmol/L
48
Explanations for the lactate threshold: accelerated glycolysis
NADH produced faster than it is shuttled into mitochondria
| - excess NADH in cytoplasm converts pyruvic acid to lactic acid
49
hypoxia
low muscle oxygen
50
explanations for the lactate threshold: recruitment of fast-twitch muscle fibers
- LDH isozyme in fast fibers promotes lactic acid formation
51
practical uses of the lactate threshold: prediction of performance
combined with VO2 max
52
practical uses of the lactate threshold: planning training programs
- marker of training intensity
| - choose a training HR based on LT
53
does lactate cause muscle soreness?
lactate production is commonly believed to cause muscle soreness
54
lactate removal is _____ following exercise
rapid
55
power athletes should experience ______ after every workout
DOMS
56
DOMS
delayed-onset muscle soreness
57
muscle soreness is _______ following routine workout
rare
58
what does cause muscle soreness?
microscopic injury to muscle fibers leads to inflammation
59
Estimation of fuel utilization during exercise: respiratory exchange ration (RER or R)
R = VCO2/VO2
60
R for fat(palmitic acid)
C16H32O2 + 23O2 --> 16CO2 + 16H2O
R = VCO2/VO2 = 16 CO2/23O2 = 0.70
61
R for carbohydrate (glucose)
R = VCO2/VO2 = 6/6 = 1.00
62
Exercise intensity and fuel selection : low intensity exercise
- <30% VO2 max
| - fats are primary fuel
63
exercise intensity and fuel selection: high-intensity exercise
- >70% VO2 max
| - carbohydrates are primary fuel
64
exercise intensity and fuel selection: "crossover" concept
- describes the shift from fat to CHO metabolism as exercise intensity increases
- due to: recruitment of fast muscle fibers, increased blood levels of epinephrine
65
McArdle's Syndrome
a genetic error in muscle glycogen metabolism
66
McArdle's Syndrome: cannot synthesize the enzyme ___________
phosphorylase
67
McArdle's Syndrome: inability to break down __________
muscle glycogen
68
McArdle's Syndrome: prevents __________
lactate production
69
McArdle's Syndrome: blood lactate levels do not _____ during high-intensity exercise
rise
70
Is low-intensity exercise best for burning fat? at low exercise intensities......
- high percentages of energy expenditure (~60%) derived from fat
- however, total energy is low
- total fat oxidation is also low
71
is low intensity exercise best for burning fat: at higher exercise intensities......
- lower percentage of energy (~40%) from fat
- total energy expended is higher
- total fat oxidation is also higher
72
exercise duration and fuel selection: prolonged, low-intensity exercise
shift from carbohydrate metabolism toward fat metabolism
73
exercise duration and fuel selection: due to an increase rate of lipolysis ....
breakdown of triglycerides --> glycerol + FFA
- by enzymes called lipases
- stimulated by rising blood levels of epinephrine
74
interaction of fat and CHO metabolism during exercise: fat burns in the flame of __________
carbohydrates
75
glycogen is depleted during ________ high-intensity exercise
prolonged
76
carbohydrate feeding via sports drinks improves endurance performance
- the depletion of muscle and blood carbs stores contributes to fatigue
- ingestion of carbohydrates can improve endurance performance
- may also improve performance in shorter, higher intensity events
77
_________ g of carbohydrate per hour are required
30-60
78
sources of carbohydrate during exercise: muscle glycogen
primary source of carb during high-intensity exercise
| - supplies much of the carbohydrate in the first hour of exercise
79
sources of carbohydrate during exercise: blood glucose
- from liver glycogenolysis
- primary source of carb during low-intensity exercise
- important during long-duration exercise
80
sources of fat during exercise: intramuscular triglycerides
- primary source of fat during higher intensity exercise
81
sources of fat during exercise: plasma FFA
- 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
82
sources of protein during exercise: proteins break down into amino acids
muscle can directly metabolize branch chain amino acids and alanine
- liver can convert alanine into glucose
83
sources of protein during exercise: only a small contribution to total energy production during exercise
- may increase to 5-10% late in prolonged-duration exercise
| - enzymes that degrade proteins (proteases) are activated in long-term exercise
84
Lactate as a fuel source during exercise: 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 liver (Cori cycle)
85
lactate as a fuel source during exercise : lactate shuttle
lactate produced in one tissue and transported to another
86
Cori cycle
lactate as a fuel source
- lactate produced by skeletal muscle is transported to the liver
- liver converts lactate to glucose (gluconeogenesis)
- glucose is transported back to muscle and used as a fuel
87
liver converts lactate to ______
glucose
