Low blood pressure or hypotension is a condition where the systolic and diastolic pressure falls below 90 and 60 (mm Hg) respectively. Blood pressure is usually measured in millimetres of mercury, and normal blood pressure is usually slightly less than 120/80 mm Hg.
To have low blood pressure is not always a concern; however, chronic hypotension can cause a lack of blood flow to the brain, causing dizziness, blackouts or loss of consciousness, and may even be life-threatening in severe cases.
More often, low blood pressure is a symptom of a different concern, such as plaque build-up, a heart disorder or aging related medical conditions, making it necessary to pay attention to signs of low blood pressure in its initial stages.
Hypotension is classified into a few major types, and these may entail different low blood pressure treatments by doctors. These include:
This kind of drop in blood pressure is also termed orthostatic hypotension and is diagnosed if there is an abnormal lowering of blood pressure when standing up suddenly. If a person who is lying or sitting down stands up and the heart is unable to adjust the flow of blood to suit the posture, it can result in a lack of adequate blood supply to the brain causing symptoms of low blood pressure such as dizziness or even loss of consciousness.
Usage of certain drugs, both prescription and recreational, as well as an underlying medical condition such as heart or liver disease cause the heart and the endocrine system to be affected and thus unable to immediately compensate for the downward movement of the blood when standing up.
Loss of consciousness, concussion and otherwise fainting due to an acute drop in blood pressure can occur due to the brain and the heart not receiving the correct signals from the nervous system, causing blood vessels to become incapable of dilating or constricting to maintain blood pressure. This is also known as neurally mediated hypotension or vaso-vagal syncope.
'Prandial' refers to the consumption of food, and sometimes eating a large meal can cause low blood pressure since the blood flow to the digestive system increases at this time, causing blood vessels to be dilated. Ordinarily, the heart would pump more blood to maintain the blood pressure, but in people with symptoms of low blood pressure, this does not happen, and instead, they experience fatigue and dizziness.
Blood pressure is one of the vital signs that are calculated to determine individual health, along with pulse rate, rate of respiration, and body temperature. It is the pressure generated as the heart contracts and expands while purifying the blood and exchanging the gases it carries.
A network of blood vessels carries the blood to and from the heart to the rest of the body, and if the volume of blood being pumped becomes low due to certain reasons, it causes hypotension resulting in a lack of adequate oxygen and nutrition. Even as the signs of low blood pressure are not always obvious, many otherwise healthy people can have hypotension because of this. There are several medical reasons that lead to low blood pressure including:
Fluctuations in blood pressure is not abnormal during pregnancies since the body's circulatory system undergoes expansion and there are changes to the production of certain hormones, and low blood pressure is common at this time. It returns to normal soon after delivery, but may require medical attention if it causes more severe symptoms.
A healthy heart is capable of offsetting any drop in blood pressure by pumping an additional amount once it receives a signal from the brain. Heart attacks, arterial blockage in the heart or heart valve concerns render the heart incapable of supplying a more constant blood flow and may cause low blood pressure.
The endocrine system affects several signalling mechanisms in a healthy body, and an imbalance in its production of hormones can cause a drop in blood pressure. Thyroid and insulin conditions are often cited as causes of low blood pressure.
A lack of nutrients such as vitamin B-12, iron, omega 2 &3 fatty acids and folate in the body results in a drop of production of red blood cells, affecting the blood's ability to carry sufficient oxygen. A low blood pressure diet is often prescribed to counter any symptoms and works effectively in a majority of cases.
The kidneys maintain a sufficient balance of nutrients and water to aid blood flow. However, kidney disease resulting in either dehydration or overhydration can lead to an imbalance of electrolytes and constriction of blood vessels causing impediment to blood flow.
A rare but recognized cause of low blood pressure is shock arising from severe infection and results from the infection entering the bloodstream.
A severe reaction to an allergen can also cause symptoms of low blood pressure by causing the heart to beat irregularly and impeding the flow of blood.
Some medicines for heart conditions, hypertension or depression can cause dilation of blood vessels resulting in sudden drops in blood pressure. Only in certain cases where patients may have other compounding medical conditions, the effects of low blood pressure may be more obvious. More often, the lowered pressure is a mild side effect of the medication and not much cause for concern.
Unless acute, the effects of low blood pressure do not manifest as symptoms in many individuals. Chronic sufferers of low blood pressure would need to seek medical consultation if they experience:
- Lightheadedness or dizziness
- Chronic fatigue
- Cold sweaty skin
- Shallow and rapid breathing
- Confusion or mental fog
- Loss of consciousness, concussion
- Weak pulse
Some people become more prone to low blood pressure due to a few factors such as age, ongoing medication, certain heart or neurological diseases or medical procedures. If symptoms of low blood pressure remain recurring despite care at home or change in diet or you, this may be due to:
It is generally understood that the heart as well as the nervous and endocrine systems become weaker with age, and if this affects vitality in the body, several effects of low blood pressure may be witnessed. These need to have heightened consideration if the individual has a history of heart, kidney or liver ailments, or shows signs of Parkinson's disease.
Prescriptions for hypertension and heart disease that include alpha or beta blockers, or a combination such as carvedilol, antidepressant drugs, or drugs for erectile dysfunction can cause low blood pressure. If you have been prescribed any such medication, it is best to remain aware of any obvious symptoms of low blood pressure that may be indicative of chronic hypotension.
Heart disease, neurological disease or damage, liver disease and renal dysfunction can all play a part in affecting the efficient flow of blood through the body. It is best to keep an eye out for relevant symptoms if you are a patient of these diseases.
A familiar instrument for diagnosis of low blood pressure is a sphygmomanometer, which has an inflatable cuff that goes around your forearm while you are sitting and supported. This cuff is worn at the heart level and must be the right size since a too large or too small cuff would result in the wrong measurement.
The inflation and deflation causes the blood vessels to constrict and relax in conjunction, and a doctor uses a stethoscope near the crook of your elbow to determine when the blood flow is constricted, and the time that it starts. The pressure diagnosed at these two times is what is noted as your blood pressure.
The pulse rate is also an important indicator of any abnormalities in blood pressure, and a doctor may repeatedly measure your pulse in addition to measuring blood pressure. A rapid, shallow beating of the pulse may indicate inability of the heart to pump adequate blood through the body. Sometimes, an electrocardiogram may also be used for accurate measurement of the heart rate, or a blood sugar test may be prescribed to determine any symptoms or effects of low blood pressure. A "tilt-table test" that simulates a change in posture while lying down on a table may also be prescribed to check for orthostatic hypotension.
Diagnosis depends on the outcome of these tests and is relatively simple to do. Medical history is also a consideration when determining if a person has signs of low blood pressure, or a more short-term incident.
Unless accompanied by other conditions, low blood pressure is usually easy to treat and does not require much medication. Often, a low blood pressure diet may be prescribed, or a change in lifestyle may become necessary. Common recommendations include:
Increased intake of water: Dehydration can cause an electrolyte imbalance resulting in signs of low blood pressure, and care towards adequate hydration would be important, especially in high temperature situations, during fevers or dysentery.
Increased sodium in diet: Salted nuts, cheeses and cured fish and meats are high in sodium content, and would help stabilize blood pressure in case it is very low. Care must be taken to not overdo it, however, and for a balance to be maintained.
Limiting alcohol consumption: Alcohol consumption can cause fluctuation in heart rate and limiting its consumption for some time will help alleviate symptoms of low blood pressure in otherwise healthy individuals.
Exercise: Light exercises not involving much strain to the body help improve circulation of blood throughout, and keep the heart healthy. In cases of low blood pressure, it is important to be aware of its symptoms such as palpitations and cold skin so that exercising does not aggravate the condition.
Care during changes to posture: Postural hypotension can be alleviated with mindfulness towards standing up from a sitting or lying position. Avoiding sudden jerks would allow the body some time to recover from the blood pooling downward due to gravity, and keep the pressure steady. Getting up slowly, turning towards the side before getting out of bed and sleeping at an elevated angle are commonly recommended to correct low blood pressure.
Small, frequent meals with fewer carbohydrates: Another low blood pressure diet tip is increasing the number and frequency of meals, but cutting back on meal size. This stabilizes metabolism and would help with alleviation of symptoms of low blood pressure.
Ceasing any aggravating medication: If intake of certain medication is seen to cause dips in blood pressure, your doctor may recommend a substitute for the drug, or even stopping its consumption till pressure is stabilized.
In cases of more severe or recurrent symptoms of low blood pressure, doctors may prescribe drugs to stabilize the system. These may include:
Fludrocortisone: It is a steroid that is prescribed when the body is unable to produce enough by itself, and is often prescribed in conjunction with other steroids such as hydrocortisone. It reduces inflammation in the body and causes the body to retain more sodium. It may cause some water retention, but this is not a cause for concern since it is necessary to build blood pressure. To maintain the sodium-potassium balance, a doctor might recommend consumption of potassium-rich foods such as apricot, bananas, spinach and broccoli while on this prescription. Once the effects of low blood pressure are no longer witnessed, you may be asked to discontinue the steroid, while maintaining lifestyle and diet changes.
Midodrine: A counter to blood vessel dilation, midodrine is a what is called a vasopressor and constricts small blood vessels to increase blood pressure. It is usually prescribed in cases of postural (orthostatic) hypotension and the dosage is gradually increased over time to prevent side effects.
A balanced meal with complex carbohydrates, fish, lean meat, fruits and cooked vegetables goes a long way in preventing hypotension. Changing meal patterns to make them more frequent and less heavy prevent as well as address postprandial fatigue and hypotension.
On diagnosis of a dip in BP, a low blood pressure diet that supplies adequate sodium, and potassium while maintaining blood sugar levels is generally recommended for patients. Increased consumption of non-alcoholic beverages helps maintain adequate hydration and is recommended. Increasing salt quantities or addition of soy sauce in everyday cooking is a simple change that combats effects of low blood pressure and may be suggested by your doctor.
Everyday exercise such as a 30-minute walk or light running can serve to improve circulation and alleviate any existing symptoms of low blood pressure. It is best to go with a companion if already a patient of hypotension, in case episodes of blurry vision, giddiness, or fainting happen during these times.
It is necessary to avoid undue stress to the body and sudden, jerky movements through heavy lifting and other strenuous exercise so that the flow of movement is smooth. Discipline and consistency regarding exercise aids the underlying causes of low blood pressure, while alleviating its symptoms as well.
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