The cardiac variables are a series of variables that help us explain the functioning of the cardiovascular system. They can be summed up as:

Heart Rate (HR)

HR is defined as the number of heartbeats, or contractions, per minute (bpm). The average HR of a healthy person at rest is between 60-70 bpm.

Stroke Volume (SV)

SV is the volume of blood pumped by the heart in a single heartbeat. However, blood is pumped in different directions by both left and right ventricle. A normal SV for a resting healthy individual should be around 70 mL/beat.

Cardiac Output (CO)

CO can be defined as the volume of blood pumped by the heart per unit of time. CO is calculated multiplying HR and SV. Consequently, CO is measured in units such as liters per minute (L/min). Normal CO for a resting healthy person is around 5 L/min.