Heart Rate, Stroke Volume & Cardiac Output (OCR GCSE Physical Education (PE)): Revision Note

Cardiac output, stroke volume & heart rate

• Heart rate (HR) = the number of times the heart beats in one minute

  • This is measured in beats per minute or bpm

  • The average resting HR is approximately 72 bpm

    • The heart rate of a fitter individual will be lower than that of a less fit individual; this is because of their heart will have become stronger through exercise and therefore is able to pump more blood per beat which require it to beat less often

• Stroke volume (SV) = the amount of blood that is ejected from the heart by the left ventricle with one contraction

  • This is measured in millilitres per beat or ml per beat

  • The average resting SV is approximately 70 ml

    • The stroke volume of a fitter individual will be larger than that of a less fit person; this is because their heart muscle is stronger and their heart is larger, so more blood can be pumped with each beat

• Cardiac output (Q) = the amount of blood pumped from the heart every minute

• This can be calculated using the following equation:

Cardiac output (Q) = stroke volume (SV) x heart rate (HR)