If blood pressure is too low, not enough blood reaches all parts of the body; as a result, cells do not receive enough oxygen and nutrients, and waste products are not adequately removed. Even so, having low blood pressure is generally better than having high blood pressure.
Healthy people who have blood pressure that is low but still in the normal range (when measured at rest) tend to live longer than those who have higher normal pressure. The normal range of blood pressure in adults or people above 18 years is between 90/60 mm Hg to 140/90 mmHg. The best time to check your Blood pressure using BP machine, is in the morning using left arm please, and not the right arm. The body has several compensatory mechanisms that control blood pressure.
They involve changing the diameter of veins and small arteries (arterioles), the amount of blood pumped from the heart (cardiac output), and the volume of blood in the blood vessels. These mechanisms return blood pressure to normal after it increases or decreases during normal activities, such as exercise or sleep.
Veins can widen (dilate) and narrow (constrict) to change how much blood they can hold (capacity). When veins constrict, their capacity to hold blood is reduced, forcing more blood into arteries. As a result, blood pressure increases. Conversely, when veins dilate, their capacity to hold blood is increased, forcing less blood into the arteries.
As a result, blood pressure decreases. The more blood pumped from the heart per minute (that is, the larger the cardiac output), the higher the blood pressure- as long as resistance to blood flow in the arteries remains constant. The body can change the amount of blood pumped during each heartbeat by making the heart rate slower or faster or by making each contraction weaker or stronger.
The amount of blood going to the kidneys is twenty per cent of the blood volume. o increase or decrease blood volume, the kidneys can vary the amount of fluid excreted in urine. When a person is bleeding, blood volume and thus blood pressure decrease. There are a lot of compensatory mechanisms taking place for a person to overcome low pressure when bleeding is stopped. The kidneys decrease their production of urine.
Thus, they help the body to retain as much fluid as possible to return to the blood vessels. Eventually, the bone marrow and spleen produce new blood cells, and blood volume is fully restored. Nonetheless, these compensatory mechanisms have limitations.
For example, if a person loses a lot of blood quickly, these mechanisms cannot compensate quickly enough, and blood pressure falls.
The commonest cause of low blood pressure in our daily environment is when people lose a lot of fluid during attacks of diarrhoea like in cholera due to decrease in blood volume. As a result those patients dehydrated will be given intravenous fluid as drips to over come the shock. If not restored immediately death occurs. Excessive alcohol intake can cause dilatation of blood vessels to cause low blood pressure.
Heart conditions due to impaired valves may also cause low pressure due to inability of pumping blood to parts of the body. Drugs that lower blood pressure may also cause low blood pressure if not properly monitored. If the kidneys are damaged will fail to regulate blood pressure and instead may cause high blood pressure.
Take care of your kidneys if you are diabetic and have high blood pressure because of the greater role the organs play in the control of blood pressure and excretion of waste products in the form of urine. When blood pressure is too low, the first organ to malfunction is usually the brain.
The brain malfunctions first because it is located at the top of the body and blood has to fight gravity to reach the brain. Consequently, most people feel dizzy or light - headed when they stand, and some may even faint. People who faint fall to the
floor, usually bringing the brain to the level of the heart. As a result, blood can flow to the brain without having to fight gravity, and blood flow to the brain increases, helping protect it from injury.
However, if blood pressure is low enough, brain damage can still occur. Low blood pressure occasionally causes shortness of breath or chest pain due to an inadequate blood supply to the heart muscle (angina). All organs begin to malfunction if blood pressure becomes sufficiently low and remains low; this condition is called shock. The disorder causing low blood pressure may produce many other symptoms, which are not due to low blood pressure itself.
For example, an infection may produce fever. Some other symptoms seen are cold clammy extremities, and in light skin individual’s skin may turn blue due to improper oxygenation. Sometimes people feel that their blood pressure is low temporarily, will need to lie down flat so as to allow blood to go to the brain by raising their legs higher than the head if dizziness is reported.
If a person is able to drink and has fainted because of low blood pressure, will need a rest and can be given a cup of tea, or coffee or take sprite/seven up with a bit of salt added to it. Please note if patient will not need surgical treatment and is not diabetic such drinks can be given. The best is to seek medical advice. There is need to seek medical attention for further investigations on people who have low blood pressure.