Measures of Heart Performance
Physical Education: AQA GCSE, topic 1.2.6
Heart Performance
There are 3 key measures of heart performance:
Heart rate
- Heart rate (HR) is the number of times the heart beats (usually measured in beats per minute or bpm).
Stroke volume
- Stroke volume (SV) is the volume of blood that the left ventricle ejects (pumps out) with each beat.
Cardiac output
- Cardiac output (Q) is the volume of blood that the heart can pump out per minute (usually measured in litres per minute or L/min).
Effects of Exercise on the Heart
Exercise increases the body's oxygen demands. The following changes happen in the heart to help more oxygen to be distributed throughout the body:
Heart rate
- Heart rate increases. This results in an increase in cardiac output because more oxygenated blood is leaving the heart each minute.
- An anticipatory rise is where the heart rate increases just before physical activity. This happens because the body releases adrenaline when it expects physical activity.
Stroke volume
- Stroke volume increases. This causes an increase in cardiac output because more oxygenated blood is being ejected from the left ventricle with each beat.
Cardiac output
- Cardiac output increases.
- This is because any increase in stroke volume or heart rate causes an increase in cardiac output.
Test yourself on Measures of Heart Performance
What are the key measures of heart performance?
Which term refers to the volume of blood ejected by the left ventricle with each beat?
What is the effect of exercise on the body's oxygen demands?
What do we call it when the heart rate increases just before physical activity?
Effects of exercise on the heart