High blood pressure (“HBP”) is a common medical diagnosis, especially as we age.
Blood pressure is determined by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries – the higher the force against artery walls – the higher your blood pressure is.
For most adults, there’s no identifiable cause of HBP or are there usually any symptoms. This type of high blood pressure, called essential hypertension or primary hypertension, tends to develop gradually over many years.
Some people have HBP caused by an underlying condition (e.g., heart or kidney condition). This type of HBP, called secondary hypertension, tends to appear suddenly and usually causes higher blood pressure than does primary hypertension.
Apart from pharmaceutical medication for controlling HBP typically treatment can start with a natural diet, exercise, weight control, de-stressing, etc. It is known that stress causes narrowing (“vasoconstriction”) of blood vessels; also exercise helps open up capillaries to reduce resistance to blood flow and reduce blood pressure.
In this article I want to focus on one aspect and that is the relationship between unintentional dehydration and HBP. According to Dr. F. Batmanghelidj, “essential hypertension is an adaptive process to a gross body water deficiency”. The simple truth is that dehydration can cause disease.
The blood vessels of the body have been designed to cope with fluctuation of their blood (mostly water) volume and the tissue requirements by opening and closing the different vessels. Also, when the total fluid volume in the body is decreased (e.g., dehydration), the main blood vessels also decrease their aperture (vasoconstriction).
Shunting of blood circulation is a normal routine. When we eat, for example, most of the circulation is directed into the gastrointestinal tract. This is done by closing capillary circulation elsewhere unless it is more urgent.
The Renin-Angiotensin system or RA system (active mainly in the kidneys) is activated when the fluid volume in the body is diminished. It is activated to retain water, and to do so, it also promotes the absorption of more salt (sodium).
Where there is either water or sodium deficiency in the body, the RA system brings about the tightening of the capillary beds and the vascular system. It is designed to do this so that there is no “slack” or empty space in the circulation system. This tightening of the vascular system offers resistance to blood circulation and only an increased force behind the circulating blood will ensure the passage of some fluids throughout the body.
However, the RA system can only retain water that is already in the body and it may not be enough. When the body is dehydrated a rationing system is involved (“drought management”) with more important organs taking priority. It can also mean that small capillaries may be shut down even in important organs such as the heart and brain. Dehydration over a long period of time can cause gradual damage to cells that can lead to disease.
Once water and sodium content in the body is replenished and reaches a preset level the RA system switches off reversing the vasoconstriction and the need to retain water and sodium.
Essential hypertension should primarily be treated with an increase in daily water intake. It should be noted that there is no substitute for water. Coffee, tea, alcohol, sodas, etc, contain water but are also diuretic.
The front line medical treatment of prescribing a diuretic medication for essential hypertension seems to run counter to the body’s effort to retain water. Diuretics work by changing the function of the kidneys so that more water (including salt and other minerals) reaches the bladder. The theory is it reduces blood volume (water content) and, therefore, blood pressure.
It doesn’t address the original condition that caused the HBP (which could be from dehydration) but adds a pharmacological dehydration to the already existing condition.