Question

Susan visits the doctor for a stress test before beginning a workout schedule. on the treadmill at a full run for 5 minutes, her heart rate was 150 bpm and her stroke volume was determined to be 120 ml. what is her calculated cardiac output?

Answer 1

Answer : The correct answer for cardiac output is 18 Liter per minute

Cardiac output is the amount of blood pumped by heart per minute. It is product of heart rate and stroke volume . Heart rate is number of beats per minute (bpm) and stroke volume is volume of blood pumped per beat (Liter per beat or Lpb) . Cardiac output can be calculates using following formula :

Cardiac output = Heart rate ( HR ) x stroke volume (SV )

The unit of cardiac output = Liters per minute

Given : Heart rate = 150 bpm

Stroke volume = 120 mL

Since volume is in mL , this need to be converted to L.

$120 \frac{mL}{beat} * \frac{1L}{1000mL } = 0.120 \frac{L}{beat}$

Plugging values of HR and SV in formula :

Cardiac output = $150 \frac{beats}{minute} * 0.120 \frac{Liter }{Beat}$

Cardiac output = $18 \frac{Liter}{minute}$