For the body to function properly, the heart needs to pump blood at a
sufficient rate to maintain an adequate and continuous supply of oxygen and
other nutrients to the brain and other vital organs. Cardiac output is the term
that describes the amount of blood your heart pumps each minute. Doctors think
about cardiac output in terms of the following equation:
Your stroke volume is the amount of blood your heart pumps each time
it beats, and your heart rate is the number of times your heart beats per
What is a normal cardiac output?
A healthy heart with a normal cardiac output pumps about 5 to 6
liters of blood every minute when a person is resting. The heart pumps about 75
mL each time it beats, and it beats an average of 70 times each minute.
Cardiac output = stroke volume × heart
Cardiac output = 75 mL × 70 beats per
Cardiac output = 5.3 liters per minute
When does the body need a higher cardiac output?
During exercise, your body may need three or four times your normal
cardiac output because your muscles need more oxygen when you exert yourself.
During exercise, your heart typically beats faster so that more blood gets out
to your body. Your heart can also increase its stroke volume by pumping more
forcefully or increasing the amount of blood that fills the left ventricle
before it pumps. Generally speaking, your heart beats both faster and stronger
to increase cardiac output during exercise.
Why is maintaining cardiac output so important?
Sufficient cardiac output helps maintain blood pressure at the
levels needed to supply oxygen-rich blood to your brain and other vital
WebMD Medical Reference from Healthwise
August 05, 2010
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