“Low blood pressure” means many serious problems, let us see what are all involved with our blood & its pressures
The force exerted by blood circulation on the blood vessels’ walls is known as ‘Blood Pressure’. This is the most important side of our body’s sign system or can be said as the vital signs of our body-systems.
Our body signs or the vital signs of our body-systems
The signs of our body system are breathing, heart rate and body temperature.
Generation of blood pressure
Heart pumps blood throughout our body by taking the routes of the arteries. The process is fully dependent on the responses of the arteries flowing of blood. This process is known as ‘blood pressure generation’.
How blood pressure is expressed?
Blood pressure is expressed through the terms 1) systolic and 2) diastolic blood pressure.
The systolic blood pressure or high blood pressure
The top number or systolic blood pressure is 120/80 that is the pressure generated in the arteries.
The characteristics of the system: Some pressures are exerted by our heart through arteries, which results in contractions of the heart and pumping blood into them. Systolic blood pressure means the heart is pumping blood.
The diastolic blood pressure or low blood pressure
The bottom number or the diastolic blood pressure is the pressure in the arteries due to the relaxation of the heart muscles following a contraction.
The characteristics of the system: Diastolic blood pressure means the heart is relaxing after pumping blood to the arteries.
Low blood pressure
Low blood pressure becomes so low that it causes some signs and symptoms; the reason being the low blood flow to the veins and arteries. If the blood flow is too low to carry required nutrients and oxygen to the important organs like kidney, heart and brain, the organs will fail to function properly, which in turn will either permanently or temporarily damage the organs.
Signs and symbols are the main specifications for measuring low blood pressure
Unlike the measurement of high blood pressure, low blood pressure is measured by the signs and symbols. Although 90/50 blood pressure number is considered as the low blood pressure, but many normal persons have continuous blood pressure reading as 90/50 without any symptoms, proving that they do not have the problem of low blood pressure. But the irony of the fact is those who have high blood pressure, may also develop the signs and symptoms of low blood pressure, in case there blood pressure drops down to 100/60.
Normally, pregnant women may experience decreased blood pressure during their gestation period. In some cases, the blood pressure may go down below 100/60. Hence it is always advised that a pregnant woman must be constantly under the observation of an obstetrician.
Generation of blood pressure
During diastole or the relaxation of the heart, the blood from the heart gets filled in the left ventricles. In this position, the left ventricle not only contracts but also pumps blood to the systole or arteries. During contraction of the systolic pressure or of the ventricle, the blood pressure in the arteries is higher; the reason is active ejection of blood in the arteries. At the time of relaxation of the diastolic pressure or of the ventricle, the blood pressure is lower. In this position no blood is ejected into the arteries.
If we place our fingers on the artery we can feel the pulse; the reason being the left ventricle’s contraction and also the ejection of blood.
Determining blood pressure
Two factors determine the blood pressure. They are:
1) The amount of blood pumped into the arteries by the left ventricles of the heart and
2) The flow of blood is resisted by the arteries’ walls, which is otherwise known as smaller arteries.
In normal condition, if the arteries are stiff or narrow or more blood is pumped in to it, the blood pressure is recorded to be higher. It can be said in other way that in case flow of blood gets resisted due to the narrow or stiff arteries, the blood pressure tends to be higher. The cause of arteries becoming narrower is the contraction of its surrounding muscles. With the aging factor, a person may develop atherosclerosis that in turn causes stiffness in arterioles. In case the supply of blood to the arteries is less or the arteries are either more flexible or larger, the blood pressure tends to be lower due to the less resistance to the flow of blood.
The way normal blood pressure is maintained by our body
The mechanisms of our body can not only maintain but also alter the blood flow and so the blood pressure of our body. The walls of our arteries have the sensors that can sense the pressure of blood and passes the signals to the arteries, veins, heart and also to the kidneys. These organs have the capacity to make changes in the pressure of blood that results to either increasing or decreasing blood pressure.
Adjustment of blood pressure
Several ways are there for adjusting blood pressure. First among them is the adjustment of amount of blood to be pumped by the heart to the arteries, to the veins which is known as cardiac output. Second is the arteriolar resistance and the final one is the adjusting the volume of blood.
Frequent contraction and speeding up of heart.
By frequenting the contraction, heart speeds up its rate by virtue. As it speeds up its rate of beating it forcefully pumps more blood. Both, frequenting contractions and speeding up its beating, result to more blood flow to the arteries and causing high blood pressure.
Narrowing and expanding of veins
More blood gets stored in the veins with the expansion of veins that in turn sends less blood to the heart to be pumped to the arteries. This causes less pumping of blood from heart, resulting to low blood pressure. As a reverse process, when veins get narrowed, veins get less blood to be stored returning more blood to the heart to pump to the arteries, which cause high blood pressure.
Narrowing and expanding of arteries
As the arterioles get expanded, it creates less resistance to the blood flow while decreasing the blood pressure. On the other hand, as the arterioles get narrowed, it creates more resistance while raising the blood pressure.
Response of kidney to the changes in blood pressure
With the changes of blood pressure, kidney can produce less or more amount of urine as its response. The primary component of urine is water, which is removed from blood. If kidneys make more urine, the volume or amount of blood, required for the veins and arteries, becomes less that causes blood pressure. If the other mechanisms of urine production are compared with, in regards to the adjustment of blood pressure, kidney’s production of urine can slowly affect the blood pressure over some periods of time; it may be hours or days. The rest of the mechanisms get affected in seconds.
The examples are 1) severe laceration due to some type of injury and 2) bleeding due to stomach ulcer that cause low blood pressure. In this situation, body’s response to the low blood volume & low blood pressure are very quick that makes the following adjustment, and all these increase the blood pressure:
Ø With the increase in heart rate, heart contraction’s forcefulness increases that results to more pumping of blood through heart.
Ø The narrowing of veins means more pumping of blood by the heart
Ø If the kidneys get reduced blood, it will form reduced urine that in turn will increase the amount of blood to the veins and arteries.
Ø Narrowing of arteries will increase the resistance of blood flow. By this way the adaptive responses will keep normal blood pressure, provided blood loss is not that much severe which can lead to overwhelming of responses.
Heart disease and the factors responsible for low blood pressure
1) Due to the weak heart muscle there is every possibility of reduced amount of blood pumping and the increased chances of heart failure.
2) One among the common reasons for weakening of heart muscle is the collapse of a major part of heart muscle because of repeated smaller attacks or either large or single heart attacks.
3) Other causes of weakened heart are the heart’s inability to pump blood due to medications, which are toxic in nature or myocarditis i.e. the heart muscle’s infections due to viruses.
4) The other factors may be the heart-valves’ diseases, which is known as aortic stenosis, causing reduced blood flow to the arteries from the heart.
5) Pericardium is the area that surrounds the heart where due to inflation a disorder occurs. The name of the disorder is Pericarditis. The disorder causes fluid accumulation within the pericardium and impedes heart’s ability to expand followed by the filling and ultimately pumping the blood.
6) Pulmonary embolism means clotting of blood within the veins. This is also known as deep vein thrombosis. The clotting of blood in vein means breaking it off and traveling to the heart and also to the lungs. If the clot is large, it can obstruct in the blood flow in the lung’s left ventricle, which in turn severely disturbs normal blood return to the heart for pumping. The problem of pulmonary embolism is a life threatening problem.
7) Bradycardia means a slow heart rate that lowers down heart’s capacity to pump the blood. Normally, 60 and 100 beats/minute is the resting heart rate for any healthy adult. Although below 60 and 100 beats/minute is not always considered as the signal for low blood pressure. It has been often found that some highly trained athletes are found to have heart rate 40s to 50s beats/minute and that also without any symptom. The slow heart rate beats are counterbalanced by added forceful heart contractions. In this condition, the heart pumps more blood, if compared with the non-athletes. However, in many cases bradycardia causes light headedness, fainting, dizziness and even low blood pressure.
Many common causes for bradycardia are 1) heart block, 2, sick sinus syndrome and 3) drug toxicity. In most of the cases, elderly people are the victims of this condition.
8) Syndrome of Sick sinus means failure of generation of electrical signal by the heart’s electrical system for maintaining normal heart rate. (Fast is the criteria).
9) Heart block is the result of the blockage in the specialized tissues which are responsible for transmitting electrical current to the heart. The problem is due to degeneration from medications, atherosclerosis and heart attacks. In case of heart block, all or sometimes some of the electrical signals are prevented by the heart blockage. In this condition, the normal contraction of heart gets disturbed.
10) Drug abuse or toxicity of drug. The examples are beta blockers or Lanoxin (digoxin) , used for treating high blood pressure can cause the slowing down of the electricity transmission to the heart due to chemical reaction that lead to hypo-tension or bradycardia
11) In case of tachycardia which is known as abnormality in the heart rate’s fastness. This condition can be responsible for low blood pressures. Atrial fibrillation is known to be the most common example of tachycardia. The disease atrial fibrillation is heart disorder. The characteristics of which are irregular and rapid electrical discharges from the heart muscle, causing contractions in the ventricles’ electrical discharges in an irregular and rapid way. This is a usual condition. Because of rapid contraction of ventricles, maximum filling of blood dos not happen. Other than this, even with faster contraction (due to the faster heart rate), the amount or volume of blood which was to be pumped gets decreased. Ventricular tachycardia is the other type of disorder due to abnormal heart rhythms, which can cause low blood pressure. Some of the patients get life threatening shocks.
Your overall health and low blood pressure
Low blood pressure means lower risks of heart disease, kidney disease and strokes. People with low blood pressure are the people who have the ideal body weight, people who exercise in regular way, athletes and non-smokers. Low blood pressure is not alarming as long as it does not become too low to cause symptoms and become the cause for organ damages.