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:
I had my first heart attack 26 years ago, when I was 52. I was very active
then, sometimes jogging and often walking long distances. But I was also on the
congressional staff in Washington, and the day leading up to the attack was
even more hectic than usual. My boss was introducing major legislation, and I
had crafted an important floor speech. I didn’t have time for regular meals and
ate a huge cheeseburger for dinner, then smoked three or four cigarettes.
It happened about 3 in the morning...
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.
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 keep blood pressure at the
levels needed to supply oxygen-rich blood to your brain and other vital
WebMD Medical Reference from Healthwise
March 12, 2014
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