Guest Author - Colleen Moore, RN
Fluid systems in the body are notorious for the high level of complexity in their physics. The circulatory system is no different, and it is because of this that there are so many different factors that could affect a personís blood pressure. The rate the heart pumps to the viscosity of the blood itself, blood pressure has influences from multiple factors in the body. These factors may, in turn, be influenced by outside factors such as diet, exercise, disease, or drugs. This is because of this that blood pressure has an even greater number of indirect influencers.
Letís start by discussing probably the most influential factor associated with blood pressure: the rate of pumping, more commonly referred to as the heart rate. The average heart rate for a healthy human being runs between 70 and 75 beats per minute. The higher the heart rate is, the higher the blood pressure. Another physical factor related to blood pressure is the blood volume of the body. The more blood there is in the body, the higher the rate of blood return to the heart and the higher the blood pressure. There is a correlation between salt intake and blood volume in many people, though the amount to which it raises blood pressure varies.
Resistance and viscosity are two other major influencing factors in blood pressure. Resistance here relates to the size of blood vessels as well as the smoothness of these vessels. There are things in the body that affect the size of blood vessels. Some make them thinner, which increases blood pressure, while others do the opposite. Fatty acids are responsible for the smoothness of blood vessels, because the more that is deposited on the walls, the less resistance there is. Viscosity, on the other hand, is the thickness of the blood flowing through the body. The thicker the blood is thatís pumping through a bodyís veins, the higher the blood pressure will be. Certain illnesses affect the viscosity of blood, as well as the level of sugars in the blood.
While thus far high blood pressure has been the effect of these factors, there are certainly ones that influence low blood pressure as well. Some causes of low blood pressure include sepsis, hemorrhaging, certain toxins, and hormonal abnormalities. On a lighter note, simply sitting and standing could lower blood pressure as well, though the factors that influence low blood pressure are usually more severe.