Cardivascular System During Exercise and Recovery Flashcards
What happens when the intensity of exercise increases?
It moves from submaximal intensity to maximal intensity.
What key words describe submaximal intensity?
Aerobic, long duration, endurance, blow anaerobic threshold, low, moderate intensity
What key words describe maximal intensity?
anaerobic, short duration, short bursts, at or above anaerobic threshold, high intensity.
What is the effect of submaximal exercise on heart rate?
- increase in HR before exercise = anticipatory rise due to adrenalin.
- fast increase in HR at start of exercise to cop with increased demand for oxygen from muscles
- HR plateaus, as the body reaches a steady state, as the supply of oxygen has now caught up with the demand from the muscles.
- fast decrease at the end of exercise during the first stage of recovery due to a decrease in VR.
- slower decrease in HR during second stage of recovery until HR returns to its pre-exercise value
What is the effect of maximal exercise on heart rate?
no steady state is reached - the supply of oxygen never catches up with the demand from the muscles.
recovery time takes longer for HR to return to its pre-exercise value due to higher intensity.
Describe the effect of different exercise intensities on stroke volume
- SV increases linearly with exercise intensity.
- SV plateaus as exercise intensity continues to rise.
3 at max intensity, SV decreases. - max SV is reached at submaximal exercise intensity.
Explain the effect of different exercise intensities on stroke volume
SV increases at submaximal exercise intensity because:
1. increased venous return and Starling’s law of the heart
SV plateaus at submaximal intensity and decreases at maximal intensity because:
2. HR increases as exercise intensity increases
3. not enough time during ventricular diastole for ventricles to fill completely.
4. less blood in ventricles at the end of diastole.
5. less blood ejected from ventricles per beat.
6. decreased SV.
7.when SV decreases due to high Hr it is called cardiovascular drift.
What happens to SV during recovery?
SV remains elevated during recovery, to maintain blood flow to the muscles in order to remove lactic acid and carbon dioxide, it reduces to its pre-exercise value gradually. A cool down helps to maintain SV
What is Starling’s law of the heart?
SV depends on venous return (VR) - the volume of blood returning to the heart. During exercise VR increases, so more blood is returning to the heart. This causes the walls of the heart chambers to stretch, therefore there are two stretches:
stretch 1 = atria
more blood enters atria = stretching of the aria walls. This stimulates the SA node causing it to increase firing rate = increased HR
stretch 2 = ventricles
more blood enters the ventricles = stretch of ventricular walls. This causes a more forceful contraction of ventricular walls = increased SV
Describe the effect of different exercise on cardiac output
- Q increases linearly with exercise intensity.
2. Q plateaus as exercise intensity continues to rise towards maximal intensity
Explain the effect of different exercise intensities on cardiac output
Q increases at submaximal exercise intensity because:
1. HR and SV ae increasing
2. Q = HR X SV
Q plateaus towards maximal intensity because:
3. HR continues to increases
4. SV decreases because of cardiovascular drift
5. so Q remains constant at its maximal value
What happens to Q during recovery?
Q reduces to its pre-exercise value gradually
HR decreases quickly, but SV remains elevated.
A cool down helps to maintain Q
What are the average values of HR at rest, submaximal and maximal?
Rest = 70bpm Submaximal = 100bpm Maximal = 220-age
What are the average values of SV at rest, submaximal and maximal?
Rest = 70ml Submaximal = 100ml Maximal = start at 100ml, but then decreases
What are the average values of Q at rest, submaximal and maximal?
Rest = 5 l/min Submaximal = 10 l/min Maximal = 20 l/min
