Rhonda Runsalot is a 20 year old woman. She is running at VO2max. Her heart rate is 200 b/min. Her stroke volume is 100 ml blood/b. Her arterial oxygen content is 20 ml O2/100 ml blood. Her venous oxygen content is 6 ml O2/100 ml blood. What is her cardiac output?

Cardiac output = 20 L/min

Explanation:

The cardiac output of a person refers to the volume of blood the heart pumps in a minute. The normal range for cardiac output is about 4 to 8 L/min. However, this can vary depending on the metabolic needs of the individual at any instant of time, for example, it is higher when exercising than  when resting.

Cardiac output is calculated from the product of the stroke volume in liters/min and the heart rate in beats/min

Cardiac output  = stroke volume * heart rate

For the individual who is running; stroke volume = 100 mL/beat or 0.1 L/beat

heart rate = 200 beats/min

Cardiac output =0.1 L/beat * 200 beats/min

Cardiac output = 20 L/min