Cardiac Output and Stroke Volume

Cardiac output is the blood volume ejected from the ventricles into the blood vessels each minute. It is calculated by multiplying the stroke volume by the heart rate.

Stroke volume is the amount of blood that one ventricle discharges per heartbeat. It is derived from the difference between the end-diastolic and end-systolic volumes.

Heart rate is the number of beats per minute.

So, for a resting male with an average stroke volume of 70 mL per beat and a heart rate of 75 beats per minute, the cardiac output comes out to 5.25 L per minute.

Exercise increases stroke volume and heart rate, enhancing cardiac output and health.

The difference between the maximum and resting cardiac output is called the cardiac reserve. It represents the heart's capacity to handle increased demand.

The cardiac reserve of an average individual is four to five times their resting cardiac output, whereas, for athletes, it can be seven to eight times.

However, individuals with severe heart disease may have minimal or no cardiac reserve.