Impact of Physical activity on SV, HR & CO

Question 1

Define Stroke Volume

Answer 1

The volume of blood pumped out by the heart ventricles each beat

Question 2

What is the average resting stroke volume?

Answer 2

70ml

Question 3

Describe the 2 factors that Stroke voume depends on

Answer 3

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.

Question 4

Explain Starling’s Law

Answer 4

Increased venous return - Greater diastolic filling of the heart - Cardiac muscke is stretched - More force of contraction - Increased ejection fraction

Question 5

Define Ejection fraction

Answer 5

The percentage of blood pumped out by the left ventricle per beat.

Question 6

What is the average Ejection fraction? what can it increase to after a period of training?

Answer 6

60% Increases to 85%

Question 7

Define Heart Rate and state the average Heart rate at rest.

Answer 7

The number of times the Heart beats per minute. 72 Bpm

Question 8

Define Cardiac output

Answer 8

The volume of blood pumped out by the heart ventricles per minute.

Question 9

What is the relationship between cardiac output (Q) and Stroke volume

Answer 9

Q= SVxHR

Question 10

What are the effects of a period of training on resting SV and resting Cardiac output (Q). Explain your answer.

Answer 10

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.

Question 11

What is the average cadiac output at rest and what does it increase to during exercise for a trained athlete and an untrained athlete?

Answer 11

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

Question 12

What is Bradycardia?

Answer 12

A decrease in resting Heart rate to below 60bpm.

Question 13

How do you calculate Maximum Heart rate

Answer 13

220 - age

Question 14

What is coronary Heart disease?

Answer 14

Coronary Heart disease occurs when your coronary arteries which supply the heart muscle with oxygenated blood, become blocked.

Question 15

What is Atherosclerosis? What causes it?

Answer 15

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

Question 16

What is Atheroma? Explain why it is life threatening?

Answer 16

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.

Question 17

What is Angina?

Answer 17

Chest pain that occurs when the blood supply through the coronary arteries to the muscles of the heart is restricted.

Question 18

Define Blood Presssure. why is it dangerous?

Answer 18

The force exerted by the blood against the blood vessel wall. increses the risk of Heart attack, heart failure, Kidney disease, Stroke and dementia.

Question 19

What is a stroke?

Answer 19

A stroke occurs when the blood supply to the brain is cut off.

Question 20

What are the two main types of stroke and explain the difference between the two.

Answer 20

Ischaemic Stroke : when blood clot stops the blood supply Haemorrhagic Stroke: When weakened blood vessels supplying the brain bursts.

Question 21

What percentage does regular exercise reduce the percantage chance of a) Heart attack? b) Stroke?

Answer 21

a) Heart Attack by 20%b) Stroke by 27%

Question 22

Explain Cardiovascular drift.

Answer 22

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.

Question 23

How can you minimise cardiovascular drift?

Answer 23

Maintain high fluid consumption before and during exercise.