Reynolds Number and Heart Disease

Last month my blood pressure increased to 150 / 100 and I started doing some exercise and reduced my salt intake. In few weeks, the BP has reduced to 135 / 90 and I intend to continue reducing it further.

High Blood pressure is a pre-cursor to heart disease. In my opinion that is not an accurate statement ! First of all, the blood flow in the arteries are similar to a fluid flow through pipes, which has been extensively researched in the field of Fluid Mechanics.

Fluid Mechanics classifies the fluid flow through pipes into 2 distinct types, Laminar flow and Turbulent flow. The nature of flow is defined by Reynolds number which is

Reynolds number = (density x velocity x length) / viscosity

An increase in density, velocity and length have a proportional effect and viscosity has an inverse proportional effect on Reynolds number.

Fluid flows are laminar for Reynolds Numbers up to 2000. Beyond a Reynolds Number of 4000, the flow is completely turbulent. Between 2000 and 4000, the flow is in transition between laminar and turbulent

You can find a lot of detail on the Internet about Reynolds number.

Heart disease is caused mainly by damaged arteries. So, how do these arteries get damaged ?

Doctors think that high blood pressure causes this damage. But I believe, what really causes the damage is the Turbulent flow !

In Laminar flow, almost all the particles move in the direction of the flow, whereas in Turbulent flow, several particles move in a direction that is perpendicular to the direction of the flow. There will be lot of eddies resulting in a higher velocity gradient at the wall of the pipe (blood vessel). This causes a higher shear stress on the wall and causes damage.

I believe doctors need to check for turbulent flows (Reynolds Number) in a patient instead of the Blood pressure. Laminar flows do not produce noise and turbulent flow produces noise which can be detected by a stethoscope and a trained ear. I am confident that some instruments can be designed to measure the noise levels and determine the level of turbulence in the arteries. I wish to see such turbulence detectors in the shelves of the pharmacy stores soon.

You can reduce the Reynolds number by increasing the diameter of the artery which will decrease the velocity of the blood flow.

If you are tense, the artery diameter is reduced. If you are relaxed, the artery diameter increases.

When you do more exercise, the peripheral artery diameters increase.

Per Pouiseuille's law, Volume Flowrate is proportional to the fourth power of diameter. Read more here. http://hyperphysics.phy-astr.gsu.edu/hbase/ppois2.html#bl3