Cardiac Output and Stroke Volume — NEET Biology
✅ Asked in NEET 2019This sequential event in the heart which is cyclically repeated is called the cardiac cycle and it consists of systole and diastole of both the atria and ventricles. As mentioned earlier, the heart beats 72 times per minute, i.e., that many cardiac cycles are performed per minute. From this it could be deduced that the duration of a cardiac cycle is 0.8 seconds. During a cardiac cycle, each ventricle pumps out approximately 70 mL of blood which is called the stroke volume. The stroke volume multiplied by the heart rate (no. of beats per minute) gives the cardiac output. Therefore, the cardiac output can be defined as the volume of blood pumped out by each ventricle per minute and averages 5000 mL or 5 litres in a healthy individual. The body has the ability to alter the stroke volume as well as the heart rate and thereby the cardiac output. For example, the cardiac output of an athlete will be much higher than that of an ordinary man.
NTA tests your understanding of cardiac output (CO) formula: CO = Stroke Volume (SV) × Heart Rate (HR). Students often confuse stroke volume (70 mL per beat) with cardiac output (5 liters/minute) or forget to convert units properly. The key trap: mixing up what each term means—SV is per beat, CO is per minute. Remember the sequence: if heart rate increases but stroke volume stays constant, cardiac output increases proportionally. Athletes have higher CO than normal individuals because they can increase both SV and HR. Practice numerical problems using the formula to master this high-yield concept.
What would be the heart rate of a person if the cardiac output is 5 L, blood volume in the ventricles at the end of diastole is 100 mL and at the end of the ventricular systole is 50 mL? (NEET 2019)
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.