chapter 5

Question 1

Acute Responses vs Chronic Adaptations

Acute responses are:

Answer 1

• Short term responses of the respiratory, cardiovascular and muscular systems to exercise.
• These short-term responses return to pre-exercise levels at the cessation of exercise.

Question 2

Acute Responses vs Chronic Adaptations

chronic adaptations:

Answer 2

-Physiological changes of the respiratory, cardiovascular and muscular system to exercise.
-As a result of long-term training.

Question 3

Acute Respiratory Responses to Exercise

Acute respiratory responses to exercise are design to:

Answer 3

-Allow more oxygen to enter the body (increase the availability of oxygen)
-assist with the removal of carbon dioxide.

Question 4

Acute Respiratory Responses to Exercise

Acute respiratory responses include:

Answer 4

• Increased respiratory rate (breathing rate) (RR)
• Increased tidal volume (TV)
• Increased ventilation (VE) or minute -ventilation
• Increased pulmonary diffusion
• Increased oxygen uptake or VO2 max

Question 5

Acute Respiratory Responses to Exercise

1. Increased Respiratory Rate (RR)

definition:
explanation:
performance link:

Answer 5

Definition:
- Respiratory rate refers to the number of breaths taken per minute.

Explanation:
- At rest, an individual’s respiratory rate is around 12 breaths per minute. This can increase significantly during exercise to 35-50 breaths per minute.

Performance Link (How does it assist with performance?):
- An increase in respiratory rate allows more oxygen to enter the body and to be taken up by the cardiovascular system. It also assists with the removal of carbon dioxide from the lungs/body.

Question 6

Acute Respiratory Responses to Exercise

2. Increased Tidal Volume (TV)

definition:
explanation:
performance link:

Answer 6

Definition:
- Tidal volume is the amount of air breathed in and out in one breath. It is measured as the number of litres per breath.

Explanation:
- At the onset of exercise, the depth of breathing (tidal volume) increases from around 0.5 litres per breath to as high as 3-5 litres per breath during maximal activity.

Performance Link:
- An increase in tidal volume allows more oxygen to enter the body and to be taken up by the cardiovascular system. It also assists with the removal of carbon dioxide from the lungs/body.

Question 7

Acute Respiratory Responses to Exercise

3. Increased Ventilation

definition:
equation:
explanation:

Answer 7

Definition:
- Ventilation is the amount of air inspired or expired per minute by the lungs. It is measured in litres per minute (L/min).

Equation:
- Ventilation = Respiratory Rate x Tidal Volume

Explanation:
- At rest, ventilation is around 5-6 litres per minute. During maximal exercise, it may increase beyond 180 and 130 litres per minute (for males and females respectively). An increase in ventilation is due to increases in tidal volume and/or respiratory rate.

Question 8

Acute Respiratory Responses to Exercise

3. Increased Ventilation

performance link:

Answer 8

Performance Link – During Submaximal Exercise:
- At the start of exercise, ventilation increases rapidly due to increases in respiratory rate and tidal volume to meet the body’s demands for oxygen. (A linear relationship exists between ventilation and oxygen consumption).
- When the muscles receive the oxygen they require, ventilation levels will plateau.

Performance Link – During Maximal Exercise:
- During maximal exercise, ventilation continues to increase linearly until it reaches the ventilatory threshold.
- Beyond this point it increases at non-linear rates until the cessation of exercise.
- Further increases in ventilation during maximal exercise are due to increases in respiratory rate.
**Note: Tidal volume has a maximum capacity therefore when it reaches maximum levels it cannot contribute further to increases in ventilation.

Question 9

Acute Respiratory Responses to Exercise

4. Increased Pulmonary Diffusion

definition:
explanation:

Answer 9

Definition:
- Diffusion is the process whereby a gas moves from an area of high concentration to an area of low concentration.

Explanation:
In this case, pulmonary diffusion is the process whereby:
- Oxygen moves from an area of high concentration in the alveoli to areas of low concentration in the capillaries (bloodstream).
- Carbon dioxide moves from an area of high concentration in the capillaries (bloodstream) to areas of low concentration in the alveoli.

This process of gas exchange occurs in the lungs at the alveolar-capillary interface.

Diffusion also occurs in the muscle at the tissue-capillary interface whereby:
- Oxygen moves from an area of high concentration in the capillary (bloodstream) to an area of low concentration in the muscle tissue. (This oxygen is used to provide energy for muscle contraction).
- Carbon dioxide moves from an area of high concentration in the muscle (it is a by-product of aerobic respiration/aerobic energy production) to an area of low concentration in the bloodstream.

Question 10

Acute Respiratory Responses to Exercise

4. Increased Pulmonary Diffusion

performance link:

Answer 10

Performance Link:
- During exercise, the diffusion capacity / rate of diffusion is increased due to an increase in the surface area of the alveoli and the muscle tissue.
- This allows more oxygen to enter the bloodstream and to be taken up by the muscle for energy production and greater amounts of carbon dioxide to be removed from the body.

Question 11

Acute Respiratory Responses to Exercise

5. Increased Oxygen Uptake (VO2 max)

definition:
equation:

Answer 11

Definition:
- Oxygen Uptake is the amount of oxygen that can be taken in, transported and utilised by the body for energy production.

Equation:
- Cardiac output (L/min) and arteriovenous oxygen difference (mL/100 mL).

Question 12

Acute Respiratory Responses to Exercise

5. Increased Oxygen Uptake (VO2 max)

explanation:
performance link:

Answer 12

Explanation:
- At rest, the body consumes oxygen at a rate of approximately 0.25 litres per minute.
- During exercise, oxygen uptake increases as the working muscles use more of the oxygen made available to provide energy for muscle contraction.
- A linear relationship exists between oxygen uptake and exercise intensity. As exercise intensity increases, oxygen uptake increases in direct proportion to it.

Performance Link:
- An increase in oxygen uptake allows more oxygen to be taken in, transported and utilised by the muscle for aerobic energy production.
- It also assists with the removal of carbon dioxide at the muscle.

Question 13

Acute Cardiovascular Responses To Exercise

Acute cardiovascular (heart, blood vessels and blood) responses to exercise are design to:

Answer 13

• Deliver more oxygen (blood) to the working muscles in order to meet the body’s increased demand for energy.
• Speed up the removal of carbon dioxide and other waste products from the muscle.

Question 14

Acute Cardiovascular Responses To Exercise

Acute cardiovascular responses to exercise include:

Answer 14

-Increased heart rate
-Increased stroke volume
-Increased cardiac output
-Increased blood pressure
-Redistribution of blood flow to the working muscles
-Increased arteriovenous oxygen difference
-Increased venous return
-Decreased blood volume

Question 15

Acute Cardiovascular Responses To Exercise

1. Increased Heart Rate (HR)

definition:
equation:

Answer 15

Definition:
-Heart rate is the number of times the heart contracts or beats per minute. It is expressed as bpm (beats per minute).

Equation:
- Maximal Heart Rate is calculated by the following formula: 220 – age.

Question 16

Acute Cardiovascular Responses To Exercise

1. Increased Heart Rate (HR)

explanation:
performance link:
additional information:

Answer 16

Explanation:
-At the onset of exercise, heart rate increases directly in proportion (linearly) with increases in exercise intensity until maximal levels are reached.

Performance Link:
- The increase in heart rate helps to increase oxygen delivery to the working muscles to meet the muscles increased demand for oxygen. It also assists with the removal of carbon dioxide and waste products from the muscle.

Additional Information:
-Trained athletes have a lower resting heart rate and submaximal intensity exercise heart rate compared to untrained athletes

Question 17

Acute Cardiovascular Responses To Exercise

2. Increased Stroke Volume (SV)

definition:
explanation:

Answer 17

Definition:
- Stroke volume is defined as the amount of blood ejected from the left ventricle with each beat (contraction) of the heart.
- It is measured in millilitres (ml) or litres (l)

Explanation:
-At rest, the stroke volume of an untrained athlete is 60 – 80ml.
-This can increase to 110 – 130ml during maximal intensity exercise.

Question 18

Acute Cardiovascular Responses To Exercise

2. Increased Stroke Volume (SV)

performance link:
additional Information:

Answer 18

Performance Link:
- An increase in stroke volume during exercise allows more oxygen to be delivered to the working muscles to be used for energy production.
- It also assists with the removal of carbon dioxide and waste products from the muscle.

Additional Information:
- Females tend to have lower stroke volumes than males, both at rest and during exercise, as a result of their smaller heart size.
- Trained athletes (both male and female) have larger stroke volumes compared with their untrained counterparts.

Question 19

Acute Cardiovascular Responses To Exercise

3. Increased Cardiac Output (Q)

definition:
equation:
explanation:

Answer 19

Definition:
- Cardiac output is the amount of blood ejected from the left ventricle per minute.
- It is measured in ml/min or l/min.

Equation:
- Cardiac Output = Stroke Volume (SV) x Heart Rate (HR)

Explanation:
- During exercise, cardiac output increases as a result of increases in both heart rate and stroke volume.
- This increase in cardiac output is designed to bring about an increase in oxygen delivery to the working muscles and heart.
- Heart rate is the most important factor contributing to increases in Cardiac Output during exercise.

Question 20

Acute Cardiovascular Responses To Exercise

3. Increased Cardiac Output (Q)

performance link:

Answer 20

Performance Link – Submaximal Exercise (When the athlete is not working to exhaustion):
- During submaximal exercise, cardiac output will increase rapidly at the onset of exercise in response to increases in exercise intensity.
- When the muscles receive the oxygen that they demand, cardiac output will plateau and steady state (a period where the muscles receive the oxygen supply, they demand) will be achieved.

Performance Link – Maximal Exercise (When the athlete is working to exhaustion):
- During maximal intensity exercise, cardiac out increases linearly in response to increases in exercise intensity to meet the body’s demands for oxygen.
- Stroke volume will reach maximum capacity. Further increases in cardiac output are due to increases in heart rate until maximum levels are reached.

Increases in cardiac output allows more oxygen to be delivered to the working muscles per minute for energy production. It also assists with the removal of carbon dioxide and waste products from the working muscles.

Question 21

Acute Cardiovascular Responses To Exercise

4. Increased Blood Pressure

definition:

Answer 21

Definition:
Blood pressure is the pressure exerted by the blood against the arterial wall as it is forced through the circulatory system by the action of the heart.
- It has two components: systolic blood pressure and diastolic blood pressure.

Systolic blood pressure is the pressure exerted by the blood on the arterial walls as it is ejected from the heart during the contraction phase of the heart cycle.

Diastolic blood pressure is the pressure exerted by the blood on the arterial walls during the relaxation/refilling phase of the heart cycle.

Question 22

Acute Cardiovascular Responses To Exercise

4. Increased Blood Pressure

explanation:

Answer 22

Explanation:
- Dynamic Whole-Body Exercise
During, exercise, the increase in cardiac output results in an increase in blood pressure.
- During dynamic whole-body exercise such as jogging or cycling, blood is pumped more forcefully and quickly out of the heart to meet the muscles demand for oxygen.
- This increases the pressure on the artery walls. This results in an increase in systolic blood pressure.
- Diastolic blood pressure experiences little change during dynamic whole-body exercise.

Explanation: Resistance-Type Exercise (Lifting Heavy Weights):
- During resistance-type exercise (e.g. lifting weights), large increases in both systolic and diastolic blood pressure are evident.
- With high-intensity resistance training, blood pressure can reach values as high as 480 over 350 mmHg.

Note: This acute response does not contribute to an increase in performance. Do not make reference to this acute response in exam situations unless the question asks you specifically about blood pressure.

Question 23

Acute Cardiovascular Responses To Exercise

5. Redistribution of Blood Flow to Working Muscles

definition:

Answer 23

Definition:
Blood supply is controlled in the body via the processes of vasodilation and vasoconstriction.

• Vasodilation involves an increase in the diameter of the arterioles. This allows more blood to flow to the working muscles.
• Vasoconstriction involves a decrease in the diameter of the arterioles. This reduces the supply of blood to areas of the body, specifically organ and glands when we are exercising.

It is important to be aware that the body only has approximately 5 litres of blood circulating it at any one time and this is require to provide oxygen to many working muscles depending on the nature of the activity undertaken.

Question 24

Acute Cardiovascular Responses To Exercise

5. Redistribution of Blood Flow to Working Muscles

explanation:
performance link:

Answer 24

EXPLAINATION:
At rest,
- 20% of blood flow is directed to the skeletal muscle.
- 80% of blood flow is directed to the internal organs and glands (heart, liver, kidneys, brain)

During exercise,
-80% of blood flow is directed to the skeletal muscle to meet the muscles demand for oxygen.
-20% of blood flow is directed to the internal organs and glands (heart, liver, kidneys, brain).

• This increase in blood flow to the working muscle is achieved by vasodilation occurring at the arterioles surrounding the working muscles.
• At the same time, vasoconstriction occurs at the internal organs and glands, reducing blood supply to these areas of the body.

PERFORMANCE LINK:
- The increase in blood flow to the working muscle increases the availability of oxygen at the muscle.
- This oxygen is used for aerobic energy production to fuel muscle contraction.

Question 25

Acute Cardiovascular Responses To Exercise 6. Increased arterio-venous oxygen difference (a-VO2 diff.) definition:

Answer 25

Remember arteries transport oxygenated blood away from the heart to sites around the body, whereas veins/venules transport deoxygenated blood (blood with low concentrations of oxygen) back to the heart. DEFINITION: - Arterio-venous oxygen difference is a measure of the difference in the concentration of oxygen in the arterial blood and the concentration of oxygen in the venous blood. - This is measured in millilitres per 100 millilitres of blood. - The arterio-venous oxygen difference is a measure of how much oxygen the muscles are extracting.

Question 26

Acute Cardiovascular Responses To Exercise 6. Increased arterio-venous oxygen difference (a-VO2 diff.) explanation: performance link:

Answer 26

EXPLAINATION: At rest: - The arteries contain an oxygen concentration of 20ml per 100ml of blood. - The veins contain an oxygen concentration of 15ml per 100ml of blood. Therefore the a-VO2 diff. =20-15ml per 100ml of blood = 5 ml per 100ml - At rest, the muscles demand for oxygen is low therefore they only extract approximately 25% of oxygen from the arterial blood. During exercise: - The arteries contain an oxygen concentration of 20ml per 100ml of blood. - The veins contain an oxygen concentration of 5 ml per 100ml of blood. Therefore the a-VO2 diff. =15 ml per blood - During exercise, the difference increases as the working muscles extract more oxygen from the arterial blood. PERFORMANCE LINK: An increase in a-VO2 difference increases the availability of oxygen in the working muscles. This oxygen is used for aerobic energy production and fuels muscle contraction.

Question 27

Acute Cardiovascular Responses To Exercise 7. Increased Venous Return definition: explanation:

Answer 27

DEFINITION: - Venous return refers to the volume of blood that flows back (returns) to the heart. It is a direct reflection of cardiac output. - In similar terms if the heart ejects a certain amount of blood per minute (cardiac output), then that same volume of blood must return to the heart (venous return). EXPLIANTION: - During exercise, an increase in cardiac output (Q) is accompanied by an increase in venous return. The three mechanisms that are responsible for this increase in venous return are: - The muscle pump – This is the result of the pumping action caused by repetitive muscle contractions. - The respiratory pump – This is the result of repetitive contraction of the diaphragm muscle during inspiration (breathing in) - Venoconstriction (constriction/reduction in size of the veins) NOTE: This acute response does not contribute to an increase in performance. Do not make reference to this acute response in exam situations unless the question asks you specifically about venous return.

Question 28

Acute Cardiovascular Responses To Exercise 8. Decrease Blood Volume (Plasma Volume) definition: explaination:

Answer 28

Definition: - Blood volume refers to the amount of blood in the circulatory system. - Blood has four main components: plasma, red blood cells (RBCs), white blood cells and platelets. Explanation: - During aerobic exercise, blood volume decreases. - This is as a result of plasma being lost from the body via sweat. Note: - This acute response does not contribute to an increase in performance. Do not make reference to this acute response in exam situations unless the question asks you specifically about blood volume.

Question 29

Acute Muscular Responses To Exercise Acute muscular responses to exercise are designed to:

Answer 29

- Increase the extraction of oxygen from the blood. - Increase aerobic energy production for muscular contraction. - Increase the amount of force a muscle can generate.

Question 30

Acute Muscular Responses To Exercise

Answer 30

- Increased motor unit recruitment - Increased blood flow to working muscles Increased body temperature - Decreased intramuscular energy substrate levels. For example, decreased ATP stores, decreased Creatine Phosphate (CP) stores. During prolonged endurance events – decreased glycogen stores and decreased triglyceride stores. - Increased lactate production - Increased muscle enzyme activity - Increased arteriovenous oxygen difference

Question 31

Acute Muscular Responses To Exercise 1. Increased Motor Unit Recruitment definition: explanation:

Answer 31

Definition: - A motor unit refers to a motor neuron and the muscle fibres it stimulates. Explanation: - During exercise, the central nervous system recruits more motor units by increasing the frequency of messages sent to active the motor unit. - Depending on the required strength and speed of the muscle contraction, the number of motor units recruited and the rate at which they are recruited can be adjusted.

Question 32

Acute Muscular Responses To Exercise 1. Increased Motor Unit Recruitment performance link: additional information:

Answer 32

Performance Link: - Increasing the number of motor units recruited enables the muscle to produce more forceful muscle contractions. Additional Information: - It is important to remember the ‘All or Nothing Principle.’ - When a motor unit is activated, it will contract maximally or not at all depending on the strength of the neural impulse. - If the neural impulse does not reach a certain threshold, the motor unit and the muscle fibres it stimulates will not contract.

Question 33

Acute Muscular Responses To Exercise 2. Increased blood flow to working muscles explanation:

Answer 33

Explanation: - During exercise, there is an increased demand for oxygen by the muscles. - This leads to the redistribution of blood flow from the internal organs to the working skeletal muscles. - The redistribution of blood flow occurs via the process of vasodilation of the capillaries at the muscle and vasoconstriction of the capillaries at the internal organs and glands.

Question 34

Acute Muscular Responses To Exercise 2. Increased blood flow to working muscles performance link:

Answer 34

Performance Link: - An increased blood flow to the working muscles provides the muscle with greater amounts of oxygen. - This allows the muscle, specifically the myoglobin, to extract more oxygen from the blood and utilise this oxygen for aerobic energy production to fuel muscle contraction. - Myoglobin is the protein pigment found in the muscle that is responsible for extracting oxygen from the blood. - Haemoglobin is the protein pigment found in the blood that is responsible for transporting oxygen to various sites around the body.

Question 35

Acute Muscular Responses To Exercise 3. Increased body temperature explanation:

Answer 35

EXPLAINATION: - When exercise commences, there is an increase in the rate of chemical reactions that take place in the body to provide ATP for muscle contractions. - Heat is a by-product of these chemical reactions and this causes body temperature to increase. - Increased blood flow to the muscles also results in an increase in muscle temperature.

Question 36

Acute Muscular Responses To Exercise 3. Increased body temperature performance link:

Answer 36

PERFORMANCE LINK: - During prolonged endurance activities (30+ min in length), increased/elevated body temperature can be detrimental to performance as it can lead to the onset of fatigue. - Thermoregulation is the process the body uses to keep body temperature within certain boundaries. As core temperature rises: - Blood is redistributed away from the working muscles to the skin’s surface via the process of vasodilation of the capillaries at the skin’s surface. - This allows heat to be lost from the body via sweat. - Fatigue sets in as there is less oxygen/blood flow to the working muscles, and this increases the reliance on the anaerobic glycolysis energy system.

Question 37

Acute Muscular Responses To Exercise 4. Decreased muscle energy substrate levels definition:

Answer 37

Definition: - The muscle contains ATP and energy substrates/fuels that are used for ATP production. - These fuels include creatine phosphate, glycogen and triglycerides. - Creatine Phosphate (CP or PC) is the fuel source of the ATP-CP system. - Glycogen is the fuel source of the anaerobic glycolysis energy system and the aerobic energy system. - Triglycerides are one of the fuel sources of the aerobic energy system.

Question 38

Acute Muscular Responses To Exercise 4. Decreased muscle energy substrate levels explanation: performance link:

Answer 38

Explanation: - During exercise, the muscle relies on ATP to fuel muscle contraction. - The limited intramuscular stores of ATP deplete. This increases the reliance on the three energy systems to resynthesise ATP. - Fuel sources such as creatine phosphate, glycogen and triglycerides are called upon to resynthesis ATP. - The energy system activated and fuel sources called upon is dependent on the intensity and duration of the activity. - This leads to decreases in creatine phosphate stores, glycogen stores and during prolonged endurance events (30 min+ in duration) triglyceride stores. Performance Link: - The depletion of fuel stores such as creatine phosphate, glycogen and triglycerides provide energy for the resynthesis of ATP and thus, muscle contraction.

Question 39

Acute Muscular Responses To Exercise 5. Increased lactate production definition: explanation:

Answer 39

Definition: - Lactate is a by-product of anaerobic glycolysis and the anaerobic glycolysis energy system. Explanation: - During maximal intensity activity, the anaerobic glycolysis energy system is predominant – meaning it is the major supplier of ATP for muscle contraction. - This leads to an increase in the accumulation of lactate in the muscle. It is important to be aware that an increase in lactate production does not lead to an increase in performance. Please do not discuss this as an acute muscular response to exercise unless direct reference is made to it.

Question 40

Acute Muscular Responses To Exercise 6. Increased muscle enzyme activity definition: explanation:

Answer 40

Definition: - Enzymes speed up the rate of chemical reactions. - ATPase is an enzyme that speeds up the breakdown of ATP. - Glycolytic enzymes speed up the breakdown of glycogen anaerobically (insufficient oxygen present) - Oxidative Enzymes are enzymes that speed up the breakdown of glycogen aerobically (sufficient oxygen present). - Lipolytic Enzymes are enzymes that speed up the breakdown of triglycerides (fats). Explanation: - Enzyme activity increases during exercise to produce the increased amounts of ATP required by the muscles. - Enzymes are involved in all of the chemical processes that produce energy via the three energy pathways.