Blood Pressure

The Blood Pressure calculator compute blood pressure (BP) based on cardiac output (Qc) and blood flow resistance (R).

INSTRUCTIONS: Choose units and enter the following:

• (Qc) This is the cardiac output
• (R) This is the blood flow resistance

Blood Pressure (BP):  The calculator return the pressure in millimeters of mercury (mmHG).  However, this can be automatically converted to compatible units via the pull-down menu.

Heart / Blood Calculators:

• Compute the Heart Chamber Pressure via the Law of Laplace
• Compute the Heart Wall Stress via the Law of Laplace
• Compute the Blood Flow Rate using Darcy's Law
• Compute the Change in Vascular Pressure
• Compute Blood Pressure
• Compute the Blood Volume in a Human based on their weight

The Math / Science

Blood pressure (BP) is a measure of the force being exerted on the walls of arteries as blood is pumped out of the heart.  The formula for Blood Pressure is:

BP = Qc • R

Where:

• BP is Blood Pressure
• Qc is Cardiac Output
• R is Blood Flow Resistance

BP measurements are usually taken on the left arm (above the elbow) with a ‘sphygmomanometer’ and a stethoscope. The sphygmomanometer consists of an inflatable cuff with a pressure gauge. When inflated the cuff blocks the flow of blood to the arm below the cuff.  As the cuff is allowed to slowly deflate, the measurer listens through the stethoscope to sounds as the artery opens and allows blood flow to continue again. A blood pressure range of 110/70 to 120/80 is considered normal.

It's advisable to take BP measurements when:

• Sitting and calm
• Before taking a meal (i.e. not on a full stomach)
• Before drinking coffee, alcohol, smoking cigarettes
• Every day about the same time (for comparison purposes) and record this on a chart