# Information on the Velocity of Blood; a New Parameter

The velocity of blood is the rate of blood flow through a vessel. While most people confuse blood flow with blood velocity, it is important to note that the two are very different. Velocity of blood; a new parameter, is inversely proportional to the cross sectional area of the vessel considering that the blood flow remains constant. However, the blood flow is directly proportional to the cross sectional area of the vessel.

While the cross- sectional areas of the blood vessels is a significant factor in determining the velocity of blood, there are other factors that also play a role. Let’s explore these factors to understand the velocity of blood; a new parameter in depth.

## Factors That Affect Velocity of Blood; a New Parameter

Lateral Pressure and Kinetic Energy Flow

If a vessel has varying cross sectional area, the pressure from the sideways (lateral pressure) will be directly proportional to it, while the kinetic flow will be inversely proportional. This is why when there is an increase in the kinetic energy, there will be a decrease in the velocity of the blood flow.

In addition to this Dr. B Rai also discovered the rhythmic motion of the venous valves in human beings. This also affects the blood flow and blood velocity.

Cross Sectional Area of the Vascular Bed

As discussed above, the velocity of blood is inversely proportional to the cross sectional area of the vessels. As the vascular bed increases in diameter, the velocity decreases. For instance, in the aorta or the larger arteries, the blood velocity is as low as 0.5-1 meter per second. This increases as the vessel become thinner.

Pumping of the Heart

The pumping of the blood directly affects the pressure with which the blood is pushed.  The blood velocity thus increases with the heart’s systole action and decreases with diastole action, if all other factors remain constant.

Peripheral Resistance

Since the blood flow is inversely proportional to the resistance, as the vessels dilate and resistance decrease, there will be an increase in the blood flow. However, it is quite the opposite when it comes to blood velocity; if blood vessels dilate then the velocity of the blood decreases and it only increases when the vessels constrict.

While we already know a lot about the blood flow, the velocity of blood is a relatively a new area of study. Dr. Drinker Belle Rai in his book, “Mechanical Function of the Atrial Diastole; A New Discovery”, makes tremendous strides about the motion of blood in the venous system which sheds light on the velocity of blood; a new parameter.