So now let's look at what the
blood in the heart is actually doing.
So cardiac output is the volume of blood
that is pumped by each ventricle in one minute.
Normally this volume is about 5.25 liters per minute.
We measure cardiac output by measuring the heart
rate and multiplying it by the stroke volume.
The heart rate is the number of heartbeats per
minute and the stroke volume is the volume of blood
that is pumped out by the
ventricle with each heartbeat.
So how do we regulate this?
Maximum cardiac output is usually 4 to 5 times that
of resting cardiac output in a non-athletic person.
However, in some trained athletes, our maximum cardiac
output can go up to as much as 35 liters per minute.
Also in the heart, we have
something called the cardiac reserve.
This is the difference between a resting cardiac
output and the maximal cardiac output of an individual.
Our cardiac output is going to change if
either the stroke volume or the heart rate change.
Remember, it's the stroke volume times at heart rate so
if either one of those changes whether it be up or down,
that is going to affect your cardiac output.
Cardiac output is going to be affected by factors
that lead to the regulation of stroke volume
as well as the regulation of our heart rate.