Skip to content
← Theoretical A

Q19 - Cardiac Output and Oxygen Delivery During Exercise (Fick Principle)

Theoretical A Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license
Cardiovascular Physiology

Cardiac output (CO) is the volume of blood pumped by the heart in one minute. Cardiac output is affected by the stroke volume (SV) and the heart rate (HR). Cardiac output can be measured indirectly using the Fick’s equation: CO = Q/(A-V), where Q is the rate of oxygen consumption (mL/min), A-V is the difference between oxygen concentration in the oxygenated blood (A) and in the deoxygenated blood (V). The data below were measured from a healthy person before and during physical exercise.

Parameters Before Exercise During Exercise
Rate of oxygen consumption (Q) 250 mL/min 1500 mL/min
Oxygen difference (A-V) 50 mL/L blood 150 mL/L blood
Heart rate (HR) 60 beats/min 120 beats/min

Using the information and data, determine which of the statements are true or which are false.

A. Cardiac output increased by two-fold during exercise.
B. Stroke volume during exercise was higher than that before exercise.
C. Physical exercise caused a reduction in hemoglobin's binding for oxygen in tissues, resulting in a three-fold increase in the amount of oxygen released to tissues.
D. The number of heart beats required to supply a tissue with 3000 mL of oxygen during exercise is 240.
← Previous: Q18 Next: Q20 →

Question reproduced from IBO 2016, Theoretical Paper A, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)