HR response to exercise-SV, CO Flashcards
what is sub-maximal exercise
exercise is at a low-to-moderate intensity within a performers aerobic capacity or below the aerobic thresh-hold
associated with aerobic work
What is maximal exercise
exercise is at a high intensity above a performers aerobic capacity, which will take a performer to exhaustion
associated with anaerobic work and fatigue
How to calculate maximum heart rate
220-age
What happens during steady state exercise
heart rate plateaus (level out)- which means supply meeting demand for oxygen delivery and waste removal
Describe what is happening in the graph
an initial anticipatory rise in HR prior to exercise due to release of hormone adrenaline
- a rapid increase in HR at the start of exercise to increase blood flow and oxygen delivery in line with exercise intensity
-a steady state HR throughout the sustained intensity exercise as oxygen supply meets demand
-an initial rapid decrease in HR as recovery is entered and the action of the muscle pump reduces
- a more gradual decrease in HR to the resting levels
What happens during maximal intensity exercise
heart rate does not plateu as exercise intensity continues to increase
There is a growing demand for oxygen and waste removal which HR must continually strive to meet
What is the frank-starling mechanism
increased venous return leads to an increased stroke volume, due to an increased stretch of the ventricle walls and therefore force of contraction
How does stroke volume increase during exercise
it increases in proportion to exercise intensity until a plateau is reached at aprox. 40-60 % of working capacity
Stroke volume is able to increase due to…….
increased venous return- this is the volume of blood that returns from the body to the heart.
The frank starling mechanism- shows us how SV is dependent on venous return. lower hr the more time available to maximise sv- see greater sv in trained athletes
Why does stroke volume reach a plateau during sub-maximal intensity?
increased heart rate towards maximal intensities does now allow enough time for the ventricles to completely fill with blood in the diastolic phase
this limits the frank starling mechanism
How does cardiac output respond to exericse
CO increases in line with exercise intensity and plateaus during maximal exercise.
In recovery there is a massive decrease followed by a slower decrease to resting levels
What is the average HR for an untrained performer at
rest
sub-maximal intensity
maximal intensity
70-72bpm
100-130bpm
220-age
What is the average Stroke volume for an untrained perfomer at
rest
sub-maximal intensity
maximal intensity
70ml
100-120ml
100-120ml
What is the average cardiac output of an untrained performer at
rest
sub-maximal
maximal
5l/min
10l/min
20-30l/min
What is the average HR of a trained performer at
rest
sub-maximal
maximal
50bpm
95-120bpm
220-age
What is the average Stroke volume of a trained performer at
rest
sub-maximal
maximal
100ml
160-200ml
160-200ml
What is average cardiac output of a trained performer at
rest
sub-maximal
maximal
5l/min
15-20l/min
30-40l/min
What is the Neural control mechanism of the CCC
Neural control-
chemoreceptors located in the muscles, aorta and carotid arteries inform the CCC of
CHEMICAL CHANGES in the blood stream, such as INCREASED LEVELS OF CO2 AND LACTIC ACID
proprioceptors located in the muscles, tendons and joints inform the CCC of MOTOR ACTIVITY
Baroceptors located in the blood vessel walls inform the CCC of increased BLOOD PRESSURE
What is the intrinsic control mechanism of the CCC
temperature changes will affect the viscosity (thickness) of the blood and speed of nerve impulse transmission
venous return change will affect the stretch in the ventricle walls, force of ventricular contraction and therefore stroke volume
What is the hormonal control mechanism of the CCC
Adrenaline and Noradrenaline are released from the adrenal glands increasing the force of ventricular contraction (therefore SV) and increasing the spread of electrical activity through the heart (therefore HR)
What is the cardiac control centre
a control centre in the medulla oblongata responsible for HR regulation
What is the sympathetic nervous system
a part of the autonomic nervous system responsible for increasing HR, specifically during exercise
What is the parasympathetic nervous system
part of the autonomic nervous system responsible for decreasing hR, specifically during recovery
What is HR regulation in response to exercise- Neural control
chemo- increased co2 and lactic acid levels
proprioceptors- increased motor activity
baro- increased stretch on ventricle walls
What is HR regulation in response to exercise- intrinsic control
increased temperature
increased venous return
What is HR regulation in response to exercise- hormonal control
sympathetic release of adrenaline and noradrenaline
How does the sympathetic nervous system increase HR
sympathetic nervous system increases stimulation of SA node via the accelerator nerve to INCREASE HR
greater force of ventricular contraction increases SV
Hr X sv = co INCREASED
What is the HR regulation in response to recovery- neural control
chemo- increased 02 and decreased lactic acid
proprio- decreased motor activity
baro- decreased stretch on vessel walls
What is the HR regulation in response to recovery - intrinsic control
decreased temperature
decreased venous return
What is the HR regulation in response to recovery- hormonal control
parasympathetic inhibition of adrenaline and noradrenaline
How does the parasympathetic nervous system decrease HR
Decreases stimulation of the SA node via the vagus nerve to decrease hR
reduced force of ventricular contraction reduces SV slowly
HR x SV = decreased
