Exercise Physiology Flashcards
(83 cards)
1
Q
At rest what are the needs of skeletal muscles
A
Low metabolic needs, 20-30% oxygen uptake
2
Q
What are oxygen requirements of muscle mass at rest
A
75ml/min
3
Q
What are oxygen requirements of muscle mass during severe exercise
A
300ml/min
4
Q
Why are glucose anf fats mobilised for oxidation
A
To yield ATP for muscle contraction
5
Q
Which systems undergo change in order to meet metabolic needs
A
- Cardiovascular system
- Respiratory system
- Endocrine system
6
Q
How can the amount of work in a performance task be assessed
A
By measuring the increase in oxygen uptake compared to rest
7
Q
What is VO2max
A
The measure of the maximum volume of oxygen that an athlete can use.
8
Q
What si the single best measure of cardiovascular fitness
A
VO2max
9
Q
What is isometric (static) exercise
A
Constant muscle length and increased tension
10
Q
What is dynamic exercise
A
Rhythmic cycles of contraction and relaxation; change in muscle length
11
Q
How does the body respond to isometric and dynamic exercise
A
Through adjustments to the cardiovascular system and respiratory system
12
Q
What is moderate exercise
A
Steady state attained in 2-3 minutes, can talk comfortably
13
Q
What is heavy exercise
A
Steady state not attained for 10-20 minutes, can talk but less comfortably
14
Q
What is marathon pace
A
Heavy exercise
15
Q
Where is the lactate threshold reached
A
During heavy exercise
16
Q
What is severe exercise
A
‘Working on borrowed time’- fatigue is inevitable and highly predictable
17
Q
Where is critical power/ speed
A
In severe exercise
18
Q
What is extreme exercise
A
Maximum effort for 2 minutes or less
19
Q
What are the two types of respiration
A
Aerobic and anaerobic
20
Q
Which type of respiration is long term and happens during exercise such as swimming or cycling
A
Aerobic
21
Q
Which type of respiration is short term and happens during exercise such as weight lifting or sprinting
A
Anaerobic
22
Q
How does anaerobic respiration allow muscles to generate force in the absence of oxygen
A
The combined actions of ATP/ creatine phosphate and glycolysis
23
Q
Why is anaerobic respiration less efficient
A
Lactic acid is produced
24
Q
When is anaerobic respiration prevelant
A
During the early minutes of high-intensity exercise
25
How do muscles generate force during aerobic respiration
They use oxygen through oxidative phosphorylation
26
Which type of respiration yields more ATP
Aerobic
27
When is aerobic respiration the primary method of energy production
During endurance events
28
Which type of muscle fibres are in use during anaerobic exercise
Fast twitch muscle fibres
29
Describe the characteristics of fast twitch muscle fibres
* Large in diameter
* Light in colour (low myoglobin)
* Surrounded by few capillaries
* Relatively few mitochondria
* High glycogen content (have a ready supply of glucose for glycolysis)
30
Describe the characteristics of anaerobic exercise
* Sprinting, weight lifting
* Short duration, great intensity
* Creatine phosphate and glycogen from muscle fibres
* Fast-twitch muscle fibres: IIa/IIb
31
Describe the characterstics of slow twitch muscle fibres
* Red in colour (high myoglobin)
* Surrounded by many capillaries
* Numerous mitochondria
* Low glycogen content
* Also metabolise fatty acids and proteins- broken down into acetyl CoA that enters the Krebs cycle
32
Describe the features of aerobic exercise
* Long-distance running, swimming
* Prolonged but at lower intensity
* Fuels stored in muscle, adipose tissue and liver
* Major fuels used vary with the intesnsity and duration of exercise (glucose early, FFA later)
* Slow twitch muscle fibres
33
Which type of muscle fibres are used in aerobic exercise
Slow twitch muscle fibres
34
What is oxygen consumption proportional to
Work done
35
What is caused by oxyegn consumption not immediately rising to match energy requirements
An oxygen deficit
36
What happens post exercise
ATP and CP are resynthesised.
Excess lactate is resynthesised into glucose and glycogen
37
What contributes to fatigue
Lactate formation
38
What impairs oxidative enzymes
Lactate formation
39
What happens when oxygen consumption is above aerobic energy production
Energy production is supplemented by anaerobic mechanisms.
40
What is anerobic threshold
The point at which lactate starts to accumulate in teh blood
41
What can be used to indicate a potential for endurance exercise
Anaerobic threshold
42
What provides most of the energy for muscular exercise
Carbohydrates
43
What contributes small amounts of enegy for muscular exercise
Fats
44
What is an insignificant source of energy for muscular exercise
Protein
45
What is respiratory quotient
RQ= Vol CO2 produced : Vol O2 used
Volume of carbon dioxide produced to the volume of oxygen used per unit time by the body under steady state conditions
46
Describe what happens to plasma glucose levels during exercise
Plasma glucose levels fall very little unless severe and prolonged exercise occurs
47
By how much do plasma glucose levels fall over 3 hours of continuous exercise
by 10%
48
Where is glucose derived from
Glycogen stores in skeletal muscle and liver
49
What does adrenaline stimulate
Glycogenolysis
50
What does prolonged exercise stimulate
Gluconeogenesis
51
What are gluconeogenesis and lipolysis stimulated by
Cortisol, noradrenaline, adrenaline and growth hormone
52
What is cardiac output at rest
5 L/min
53
What is cardiac output during heavy exercise
38 L/min
54
How much cardiac output is distributed to exercising muscles in heavy exercise
80%
55
What happens to blood flow to the brain during heavy exercise
It remains constant
56
What happens to blood flow to the renal and splanchnic system during heavy exercise
Circulation declines
57
What adjustments occur during heavy exercise
There are adjustments to heart rate and stroke volume which has effects of regional blood flow and blood pressure
58
What happens to the nervous system during exercise
The vagal (parasympathetic) activity declines and the sympathetic increases
59
What does an increase in symapthetic nerve activity during exercise result in
An increase in heart rate and mobilisation of blood from large veins. Causing an increase in stroke volume and more complete emptying of the ventricles
60
What happens to inactive tissues
| (regional blood flow)
Vasoconstriction due to noradrenaline and sympathetic activity
61
What happens to active tissue
| (regional blood flow)
Vasodilation of the arterioles due to the presence of metabolites and adrenaline. Results in more blood being brought to the tissue
62
Which substances are metabolites
CO2, ADP and organic acids
63
What is SVR
Systemic vascular resistance
64
What affect do increased metabolites have on blood pressure
Vasoldilation and decreased SVR
65
What affect does increased sympathetic activity and secretion of noradrenaline have on BP
Noradrenaline causesvasoconstriction and increased SVR
66
What does increased sympathetic activity and secretion of adrenaline do to blood presure
Adrenaline causes vasodialtion of the muscles and capillaries and decreased SVR
67
What is the overall effect on SVR during exercise
SVR is decreased
68
What is blood pressure
BP = CO x SVR
69
What does a decrease in SVR result in
An increase in the force of ventricular contraction which casues an increase in systolic pressure (diastolic pressure is stable)
70
Summarise the cardiovascular changes that occur during exercise
Increased exercise = increased sympathetic output anf build up of metabolites.
Increased sympathetic output = increased cardiac output, vasodilation in skeletal muscles, vasocostriction in viscera
Increased metabolites = vasodilation in active tissue
71
What effect does training have on performance
Training improves performance
72
What 3 things are required during training
Regular exercise of:
1. appropriate intensity
2. appropriate duration
3. appropriate frequency
73
What will regular training with strenuous exercise result in
1. Lowering resting HR
2. Increasing cardiac output
1. Increasing the size of the heart
74
What do cardiovascular changes result in
An increase in the maximal O2 uptake, capacity for physical work is increased
75
What effect does training have on heart size
1. Long term aerobic training increases the heart's mass and volume.
2. Enlargement occurs due to increased size of the left cavity and modest thickening of its walls
3. This improves the heart's stroke volume
4. Accelerated protein synthesis leads to individual myofibrils increasing in number and thickening
76
What effect does training have on stroke volume
An endurance athlete has a large stroke volume at both rest and exercise. The greatest increase in stroke volume occurs during the transition from rest to moderate exercise
77
What effect does training have on heart rate
1. As exercise intensity increases the HR of athletes accelerates to a lesser extent that untrained
2. Athletes achieve higher maximum O2 uptake before reaching submaximal HR
3. Larger stroke volume accounts for lower exercise HR
4. If the heart pumps large quantity of blood with each beat then adequate devlivery of blood (O2) to the active muscles requires only small increase in HR
78
What effect does training have on cardiac output (CO)
* Increase in maximum CO represents most significant change
* CO = HR x SV
* CO increases due to imporved stroke volume.
* CO increases in order to meet the oxygen requirements of exercising muscle
79
What is athlete's heart
A normal response to healthy exercise or pregnancy
80
What does athlete's heart result in
An increase in heart's muscle mass and pumping ability (walls and chamber size increase). Left ventricular mass is up to 60% greater than in untrained subjects
81
What does pathological hypertrophy lead to
An increase in muscle mass (not as increase in heart's pumping ability) due to accumulation of myocardial scarring. Can increase mass of heart by up to 150%
82
How does exercise reduce cardiovascular disease
1. Improves the heart's contractility, work capacity and circulation
2. Improves the ratio of blood lipids (HDL/ LDL/ triglycerides)
3. Controls and prevents moderate hypertension
4. Controls weight, reduces body fat and increases muscle mass
5. Alleviates stress and decreases cigarette smoking
6. Reduces insulin resistance
83
