Impact of Physical activity on SV, HR & CO Flashcards
Define Stroke Volume
The volume of blood pumped out by the heart ventricles each beat
What is the average resting stroke volume?
70ml
Describe the 2 factors that Stroke voume depends on
Venous Return; This is the volume of blood returning to the heart via the veins. Icreaes in venous return gives an increases SVThe elasticity of the cardiac fibres: this is concerned with the degree of stretch of the cardiac tissue during the diastolic phase ( Heart relaxtion phase). The more the cardiac fibres stretch the greater the force of contraction.
Explain Starling’s Law
Increased venous return - Greater diastolic filling of the heart - Cardiac muscke is stretched - More force of contraction - Increased ejection fraction
Define Ejection fraction
The percentage of blood pumped out by the left ventricle per beat.
What is the average Ejection fraction? what can it increase to after a period of training?
60% Increases to 85%
Define Heart Rate and state the average Heart rate at rest.
The number of times the Heart beats per minute. 72 Bpm
Define Cardiac output
The volume of blood pumped out by the heart ventricles per minute.
What is the relationship between cardiac output (Q) and Stroke volume
Q= SVxHR
What are the effects of a period of training on resting SV and resting Cardiac output (Q). Explain your answer.
SV increases because the heart is a muscle and hypertrophy occurs causing there to be blood pumped out per beat. The Cardiac output remains the same because you only need the same amount of energy at rest so if the SV has increased the HR will decrease.
What is the average cadiac output at rest and what does it increase to during exercise for a trained athlete and an untrained athlete?
At rest untrained athlete: Q = SVxHR 70mlx 72bpm= 5040ml (5.04L)At rest trained athlete: 84mlx60= 5.04LDuring exercise: Trained athlete:170ml x 202=34.34L During exercise:Untrained athlete: 120mlx202=24.24L
What is Bradycardia?
A decrease in resting Heart rate to below 60bpm.
How do you calculate Maximum Heart rate
220 - age
What is coronary Heart disease?
Coronary Heart disease occurs when your coronary arteries which supply the heart muscle with oxygenated blood, become blocked.
What is Atherosclerosis? What causes it?
Atherosclerosis occurs when arteries harden and narrow and become clogged up by fatty deposits.Caused by smoking, high blood pressure, lack of exercise, high levels of cholesterol
What is Atheroma? Explain why it is life threatening?
A fatty deposit found in the inner lining of an artery. If a fatty deposit breaks off it can block the artery causing a blood clot which will cause a heart attack because it stop oxygenated blood getting to the heart muscle.
What is Angina?
Chest pain that occurs when the blood supply through the coronary arteries to the muscles of the heart is restricted.
Define Blood Presssure. why is it dangerous?
The force exerted by the blood against the blood vessel wall. increses the risk of Heart attack, heart failure, Kidney disease, Stroke and dementia.
What is a stroke?
A stroke occurs when the blood supply to the brain is cut off.
What are the two main types of stroke and explain the difference between the two.
Ischaemic Stroke : when blood clot stops the blood supply Haemorrhagic Stroke: When weakened blood vessels supplying the brain bursts.
What percentage does regular exercise reduce the percantage chance of a) Heart attack? b) Stroke?
a) Heart Attack by 20%b) Stroke by 27%
Explain Cardiovascular drift.
Cardiovascular drift occurs after a period of exercise (Approx 10mins in a warm environment) when the heart rate is at a steady state. Instead of the Heart rate remaining constant it gradually increases while the stroke volume decreases. This occurs because as muscle temperature increases fluid is lost as sweat resulting in reduced blood plasma volume. This reduces the venous return and thus the stroke volume (starling’s Law). The Heart rate increses to try and maintain an incrresed Cardiac output in an attempt to create more energy to cool down the body.
How can you minimise cardiovascular drift?
Maintain high fluid consumption before and during exercise.
