Low blood pressure (Hypotension)

2021-07-27 03:12 PM

Although blood pressure varies from person to person, a systolic blood pressure of 90 millimeters of mercury or less, or 60 mm Hg or less with diastolic pressure is generally considered low blood pressure.


Low blood pressure (hypotension) seems like something to strive for higher. However, low blood pressure can cause dizziness and fainting for many people, which means they have a serious heart, endocrine, or neurological disorder. Having low blood pressure can lead to the brain and other vital organs being deprived of oxygen and nutrients, leading to a life-threatening condition, known as shock.

Low blood pressure (Hypotension) (diagnosisbook)

Although blood pressure varies from person to person, systolic blood pressure with a blood pressure of 90 millimeters of mercury (mm Hg) or less, or 60 mm Hg or less - diastolic pressure (bottom number) is usually considered low blood pressure.

Causes of low blood pressure can range from dehydration to problems with heart disease. Low blood pressure is treatable, but it's important to find out what's causing the condition so it can be treated properly.


Low blood pressure (Hypotension) (symptoms)

For some people, low blood pressure can signal a medical problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:


Fainting (syncope).

Lack of focus.

Blurred eyes.


Cold and pale skin.

Breathe fast, shallow.




In many cases, low blood pressure is not serious. If your blood pressure is consistently low but you feel good, your doctor may monitor it during your regular checkup. Even sometimes dizziness or lightheadedness can be a relatively minor issue - the result of mild dehydration from too much time in the sun or hot showers, for example. It is not a serious problem in these cases, quickly returning to normal due to only a temporary drop in blood pressure.

However, it's important to see your doctor if you experience any signs or symptoms of low blood pressure, as it can sometimes be a serious problem.


Blood pressure is a measure of the pressure in the arteries during the active and resting phases of each heartbeat. Here are the numbers, which means:

Systolic blood pressure (SBP). The first number, which is the number of pressures the heart generates as it pumps blood through the arteries to the rest of the body.

Diastolic blood pressure. The second number, which is an indicator of the pressure in the arteries when the heart rests between beats.

Guidelines define normal blood pressure as being at or below 120/80 - many experts think 115/75 is optimal.

Although it is possible to have an exact blood pressure number at any given time, blood pressure is not always the same. It can change dramatically over a short period of time - sometimes from the next heartbeat, depending on body position, breathing rate, stress level, physical conditions, medications, what to eat and drink, and even the time of day. Blood pressure is usually lowest at night and rises sharply upon awakening.

Low blood pressure

A person whose reading is considered low blood pressure may be normal for another person. Most doctors consider chronic, low blood pressure only if it causes noticeable symptoms.

Some experts define low blood pressure when systolic blood pressure is lower than 90 or 60 diastolic - just being in the low blood pressure range will be considered lower than normal. In other words, if the systolic blood pressure is perfect 115, but the diastolic pressure is 50, it is considered lower than normal.

Sudden low systolic blood pressure can also be dangerous. A change of just 20 mm Hg - a drop in systolic blood pressure from 130 to 110, for example - can cause dizziness and fainting when the brain doesn't get an adequate blood supply. And especially those with uncontrollable heavy bleeding, serious infections, or allergic reactions, which can be life-threatening.

Athletes and people who exercise regularly tend to have lower blood pressure and slower heart rates than other people. So in general, non-smokers who eat well and maintain a normal weight have lower blood pressure.

But in rare cases, low blood pressure can be a sign of serious, even life-threatening.

Problems that can cause low blood pressure

Several medical problems can cause low blood pressure. These include:

Pregnant. Because a woman's circulatory system expands during pregnancy, blood pressure can drop. During the first 24 weeks of pregnancy, systolic blood pressure usually decreases by five to 10 mmHg and diastolic blood pressure by 10 to 15 mmHg. This is normal, and blood pressure usually returns to pre-pregnancy levels after childbirth.

Heart problems. Several heart conditions can lead to low blood pressure, including a very low heart rate (bradycardia), heart valve problems, coronary heart disease, and heart failure. These problems can cause low blood pressure.

Endocrine problems. Hypothyroidism or hyperthyroidism can cause low blood pressure. In addition, other problems, such as adrenal insufficiency (Addison's disease), low blood sugar (hypoglycemia), and in some cases, diabetes can cause low blood pressure.

Loss of water. When it comes to dehydration, even mild dehydration can cause weakness, dizziness, and fatigue. Fever, vomiting, severe diarrhea, overuse of diuretics, and heavy exercise can lead to dehydration.

Shock reduces blood flow, a life-threatening complication. It occurs when low blood volume causes a sudden drop in blood pressure and a decrease in the amount of oxygen reaching tissues. If left untreated, severe shock can cause death within minutes or hours.

Bleed. Losing a lot of blood from a major wound or internal bleeding reduces the amount of blood in the body, leading to a severe drop in blood pressure.

Severe infection (bacteremia). Sepsis can occur when the infection enters the bloodstream. These problems can lead to life-threatening, low blood pressure called septic shock.

Severe allergic reaction (anaphylaxis). Anaphylaxis is a serious and potentially life-threatening allergic reaction. Substances that commonly cause anaphylaxis include foods, certain drugs, insect venoms, and rubber. Anaphylaxis can cause difficulty breathing, hives, itching, swelling in the throat, and low blood pressure.

The diet lacks nutrients. A lack of vitamin B-12 and folate can cause anemia, a condition in which the body doesn't produce enough red blood cells, causing low blood pressure.

Medications that can cause low blood pressure

Certain medications can also cause low blood pressure, including:




Drugs for Parkinson's disease.

Certain types of antidepressants (tricyclic antidepressants).

Sildenafil (Viagra), especially in combination with a cardiovascular drug - nitroglycerine.

Types of low blood pressure

Doctors often divide low blood pressure into different categories, depending on the cause and other factors. Several types of low blood pressure, including:

Orthostatic hypotension (orthostatic hypotension). This is a sudden drop in blood pressure when standing up from a sitting position, or if standing up after lying down. Normally, gravity causes blood to rush to the legs whenever standing. The body compensates for this by increasing the heart rate and constricting blood vessels, thus ensuring enough blood reaches the brain. But in people with orthostatic hypotension, this mechanism is not normal and blood pressure drops, leading to symptoms of dizziness, lightheadedness, blurred vision, and even fainting.

Postural low blood pressure can occur for a variety of reasons, including dehydration, prolonged insomnia, pregnancy, diabetes, heart disease, burns, extreme heat, varicose veins, and neurological disorders certain. Certain medications can also cause orthostatic hypotension, especially those used to treat high blood pressure - diuretics, beta-blockers, calcium channel blockers, and ACE inhibitors - as well as antidepressants and drugs used to treat Parkinson's disease and erectile dysfunction.

Orthostatic hypotension is particularly common in older adults, with 20 percent of those over 65 years of age experiencing orthostatic hypotension. However, orthostatic hypotension can also occur in young, healthy people who stand up suddenly after sitting for long periods of time or after working for a while in a squatting position. Orthostatic hypotension is usually harmless in young people.

Low blood pressure after eating. After eating, blood pressure dropped suddenly. It affects mainly older people.

Just as gravity sends blood to the legs when standing, so does the bulk of blood flow from the gastrointestinal tract after eating. Normally, the body combats this by increasing the heart rate and constricting certain blood vessels to help maintain normal blood pressure. But in some people these mechanisms fail, leading to lightheadedness, dizziness, and falls. Postprandial low blood pressure is more likely to occur in people with high blood pressure or an autonomic nervous system disorder such as Parkinson's disease. Reducing the dose of blood pressure medications and eating small, low-carbohydrate meals can help relieve symptoms.

Low blood pressure from damaged brain signals. This disorder causes blood pressure to drop after standing for long periods of time, leading to symptoms such as nausea, dizziness, and fainting.

Low blood pressure from faulty brain signals is mainly low blood pressure that affects young people, and it seems to happen because of faulty signaling between the heart and brain. When standing for a long time, blood pressure drops due to pooling of blood in the legs. Normally, the body will adjust itself to normalize blood pressure. But in people with neurogenic low blood pressure, nerves in the left ventricle of the heart receive signals from the brain that blood pressure is too high, rather than too low, and so the brain slows down the heart rate, lowering blood pressure even more. . This causes more blood to reach the legs and less blood to the brain, leading to dizziness and fainting.

Low blood pressure due to damage to the nervous system. Shy-Drager syndrome, this rare disorder causes progressive damage to the autonomic nervous system, which controls involuntary functions such as blood pressure, heart rate, breathing, and digestion. Although this condition can be associated with tremors, slowed movement, problems with coordination, and uncontrolled language, its main feature is severe orthostatic low blood pressure associated with high blood pressure. Blood pressure is very high when lying down. Many systems are incurable and often fatal within seven to 10 years of diagnosis.

Risk factors

Low blood pressure can happen to anyone, although certain types of low blood pressure are more common depending on age or other factors:

Age. Decreased orthostatic or postprandial blood pressure occurs mainly in adults over 65 years of age. Centrally low blood pressure occurs as a result of faulty signaling between the brain and heart. It mainly affects children and young adults.

Medicine. People who take certain medications, such as those used to treat high blood pressure such as alpha-blockers, have an increased risk of low blood pressure. This is especially true for adults over the age of 80.

Some diseases. Parkinson's, diabetes, and heart disease put you at risk of developing low blood pressure.


Even moderate low blood pressure conditions can cause not only dizziness and weakness but also fainting and the risk of injury from falls. And severely low blood pressure can deprive it of oxygen to perform its normal function, leading to damage to the heart and brain.

Tests and diagnostics

The goal of low blood pressure screening is to find the underlying cause. This helps determine the correct treatment and identify any heart, brain, or nervous system problems that may be causing your blood pressure to be lower than normal. To reach a diagnosis, your doctor may recommend one or more of the following tests:

Check blood pressure. Blood pressure is measured on the arm. Blood pressure is in millimeters of mercury (mm Hg) and comes in two numbers. The top number, the pressure in the arteries when the heart beats (systolic pressure). Second, or lower number, number of pressures in the arteries between beats (diastolic pressure).

Blood tests. These can provide information about your overall health as well as low blood sugar (hypoglycemia), high blood sugar (hyperglycemia or diabetes), or low red blood cells (anemia), Both can cause blood pressure to be lower than normal.

Electrocardiogram (ECG). This noninvasive test, which can be done in a doctor's office, detects heart rhythms, structural abnormalities in the heart, and problems with the heart muscle's supply of blood and oxygen. It can also indicate if you're having a heart attack or if you've had one in the past.

Sometimes, the irregular heartbeat comes and goes, and the electrocardiogram won't find any problems. If this happens, you may be asked to wear a Holter for 24 hours to record your heart's electrical activity.

Echocardiography. Noninvasive, which includes transthoracic ultrasound, provides detailed images of heart structure and function.

Stress test. Certain heart problems can cause low blood pressure when the heart is working hard. During the stress test, you will exercise, such as walking on a treadmill. You may be given medicine to make your heart work harder if you can't exercise. As the heart works harder, you will be monitored with an electrocardiogram or an echocardiogram. Blood pressure may also be monitored.

Valsalva test. This test is a non-invasive examination of autonomic nervous system functions by analyzing heart rate and blood pressure after several cycles of deep breathing: Inhale deeply and then exhale with pressure with pursed lips, as if trying to blow a hard balloon.

Tilting table test. If you have low blood pressure from standing, or from faulty brain signals, your doctor may recommend a tilt table test, which evaluates your body's response to changes in position. During the test, lie on an inclined table to raise the upper body, simulating movement from the horizontal to the vertical position.

Treatments and drugs

Low blood pressure with or without signs or symptoms, or with only mild symptoms, such as dizziness on short standing, rarely requires treatment. If symptoms are present, the best treatment depends on the underlying cause, and doctors often try to address the initial health problem - dehydration, heart failure, diabetes, or hypothyroidism, for example - more low blood pressure itself. When low blood pressure is caused by medication, treatment usually includes changing the dose of the medication or stopping it altogether.

If the cause of low blood pressure is unknown or there is no effective treatment, the goal is to raise blood pressure and relieve signs and symptoms. Depending on your age, health condition, and types of low blood pressure, this can be done in several ways:

Use lots of salt. Experts often recommend limiting salt in the diet because salt can raise blood pressure, sometimes dramatically. For people with low blood pressure, that can be a good thing. But because excess sodium can lead to heart failure, especially in older adults, it's important to check before increasing salt in the diet.

Drink more water. Although nearly everyone can benefit from drinking enough water, this is especially true if you have low blood pressure. Blood volume increases and helps prevent dehydration, both of which are important in treating low blood pressure.

Wear compression stockings. Elastic stockings are often used to relieve pain and varicose veins can help reduce blood pooling in the legs.

Medicine. Several medications, either alone or together, can be used to treat low blood pressure that occurs when standing up (orthostatic hypotension). For example, the drug fludrocortisone is commonly used to treat low blood pressure. This drug helps increase blood volume, which increases blood pressure. Doctors often use medications to raise blood pressure levels in people with chronic orthostatic hypotension. It works by limiting the ability of blood vessels to dilate, which increases blood pressure.

Lifestyle and Remedies

Depending on the reason for low blood pressure, certain steps can be taken to help reduce or even prevent symptoms. Some suggestions include:

Drink more water, less alcohol. Alcohol is dehydrating and can lower blood pressure, even if consumed in moderation. Drinking water prevents dehydration and increases blood volume.

Follow a healthy diet. Get all the nutrients you need for good health by focusing on a variety of foods, including whole grains, fruits, vegetables, lean chicken, and fish. If your doctor tells you to increase your sodium intake but doesn't like a lot of salt in your food, try using natural soy sauce - 1,200 mg sodium per tablespoon - or add a dry soup mix that's also loaded with sodium.

Slowly change body position. Dizziness and lightheadedness that occur with orthostatic hypotension can be reduced by slowly changing standing position. Before getting out of bed in the morning, take a few deep breaths and then slowly sit up before standing. Sleeping with the head of the bed slightly elevated can also help counteract the effects of gravity. If symptoms begin while standing, pull and squeeze across the thigh, or place one foot on a rock or chair and lean forward when possible. These poses encourage blood to flow from the legs to the heart.

Eat small, low-carbohydrate meals. To avoid a sharp drop in blood pressure after meals, eat several small meals several times a day and limit high-carbohydrate foods like potatoes, pasta, rice, and bread. Drinking caffeinated coffee or tea with meals can temporarily raise blood pressure, in some cases, by 3-14 millimeters of mercury (mm Hg). But since caffeine can cause other problems, check before increasing your coffee intake.

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