Acute Responses To Exercise

Question 1

What is an Acute Response?

Answer 1

An Acute Response refers to a change in a particular parameter of the body that occurs during exercise and returns to resting level state upon conclusion.

Question 2

What is the Respiratory System responsible for?

Answer 2

The Respiratory System is responsible for the delivery of oxygen to, and the removal of carbon dioxide from, the cells of the body.

Question 3

What is Ventilation?

Answer 3

Ventilation refers to how litres of air is breathed in or out per minute. When exercise commences, Respiratory Rate (The number of breaths taken per minute) and Tidal Volume (The amount of air inspired or expired per minute) increase ventilation dramatically.
V = TV x RR

Question 4

What happens at high intensities in relation to Ventilation?

Answer 4

At high intensities, Tidal Volume plateaus and any further increase in ventilation is due to further increases in the Respiratory Rate. Ventilation continues to increase until the cessation of exercise

Question 5

Can Ventilation increase before exercise is undertaken?

Answer 5

Yes, this is due to an anticipatory rise in relation to the exercise that is about to be completed

Question 6

What is the Ventilatory Threshold?

Answer 6

Ventilatory Threshold refers to the point where ventilation increases at a non-linear rate. approx 65-75% of maximum oxygen consumption

Question 7

During light to moderate exercise, the relationship between ventilation and oxygen consumption is …

Answer 7

Linear

Question 8

What is Diffusion

Answer 8

Diffusion refers to the movement of molecules from an area of high concentration to low concentration.
Increase in Diffusion =
Greater 02 at muscle
Greater CO2 removal

Question 9

Where does Gaseous Exchange occur?

Answer 9

In the lungs at the alveolar-capillary interface

In the muscle at the tissue-capillary interface

Question 10

How does Diffusion of Gases occur in the lungs?

Answer 10

In Lungs, the oxygen concentration is high, so oxygen diffuses from the alveoli into the bloodstream.
Carbon Dioxide levels in the blood are high, so carbon dioxide moves from the blood into the alveoli via a diffusion path

O2 -> alveoli -> bloodstream
CO2 -> bloodstream -> alveoli

Question 11

How does Diffusion of Gases occur in the muscles?

Answer 11

In the muscles, blood oxygen concentration is high, so oxygen diffuses into the muscle from the blood. Carbon Dioxide levels in the muscle are high, so carbon dioxide moves from the muscle into the blood stream via a diffusion path

O2 -> blood -> muscle
CO2 -> muscle -> blood

Question 12

During exercise what happens at the alveoli and muscle as a result of diffusion?

Answer 12

There is an increased surface area of the alveoli and muscle tissue, therefore, greater amounts of oxygen and carbon dioxide can be exchanged at the alveoli and muscle.

Question 13

What is the Cardiovascular System responsible for?

Answer 13

Delivering greater amounts of oxygen and energy substrates to the working muscles.

Question 14

What is Cardiac Output? is it higher for a trained or untrained athlete?

Answer 14

Cardiac Output refers to how many litres of blood the left ventricle pumps per minute (avg. 23L during exercise). HIGHER FOR TRAINED
Q = HR x SV

Question 15

What is Stroke Volume? is it higher for a trained or untrained athlete?

Answer 15

Stroke Volume refers to how many millilitres of blood the ventricles pump per beat (avg. 70ml/bt during rest). Plateaus at around 40-60% of one’s VO2 Max
HIGHER FOR TRAINED

Question 16

What is Heart Rate?

Answer 16

Heart Rate refers to the amount of heart beats per minute (avg. 80 beats during rest).

Question 17

What is Blood Pressure?

Answer 17

Blood Pressure refers to the amount of pressure that is exerted against the arteries when the ventricles contract (systolic) and relax (diastolic) (avg. 120/80).

Question 18

What is Venous Return?

Answer 18

Venous Return refers to the amount of blood that is returned back to the heart via the veins. Venous Return is increased via three mechanisms: the muscular pump, the respiratory pump and venoconstriction

Question 19

What is Blood Volume?

Answer 19

Blood Volume refers to the volume of blood which decreases as a consequence of sweating. Factors that can determine how much is lost is the intensity, duration and environmental.

Question 20

What is Arteriovenous Oxygen Difference?

Answer 20

AVO2 Difference refers to the difference in oxygen concentration in the arterioles compared to the venules.

Question 21

What is Redistribution of Blood Flow?

Answer 21

Redistribution of Blood Flow refers to the redirection of blood away from areas where it is not needed to working muscles. Vasoconstriction refers to the decrease in the diameter of a blood vessel, resulting in a decrease in blood flow whereas Vasodilation refers to the increase in the diameter of a blood vessel, resulting in an increase in blood flow

Question 22

What is Oxygen Consumption?

Answer 22

Oxygen Consumption is the volume of oxygen that can be taken up and used by the body. As intensity increases, so does oxygen consumption

Question 23

What is Increased Blood Flow?

Answer 23

Increased Blood Flow is the amount of blood that is delivered to working muscles, thus providing more oxygen. Through the dilation of skeletal capillaries, they can allow for more blood to flow to muscles which results in a larger blood volume reaching the muscle. It also increases the surface area resulting in increased diffusion rates

Skeletal capillaries dilating -> more b flow, large b volume, increased diffusion

Question 24

What is Motor Unit Recruitment?

Answer 24

Motor units are the way in which muscles are controlled by the Central Nervous System (CNS).
Increase in motor unit recruitment by the CNS = more motor units are contracted, and results in a greater force being produced by the working muscle.

Question 25

What is the All or Nothing Principle?

Answer 25

The All or Nothing Principle is when an entire motor unit will contract maximally or not at all.

Question 26

What are Energy Substrates?

Answer 26

The chemicals that are required to resynthesis ATP (PC, Glycogen, Triglycerides)

Question 27

What does an increase in Diffusion allow?

Answer 27

More O2 to working muscles

More CO2 to be removed as a result of aerobic respiration

Question 28

What is the difference between absolute and relative VO2 max?

Answer 28

Absolute VO2 max. results do not take into account the athlete’s body weight (kg). The greater the mass, the less oxygen is used per kilogram per minute, resulting in a lower relative VO2 max.

Question 29

What is VO2 max and how is it measured?

Answer 29

VO2 max is the measurement of the maximum amount of oxygen that an individual can utilize during intense, or maximal exercise. It is measured as milliliters of oxygen used in one minute per kilogram of body weight.