Low blood pressure (hypotension) – Symptoms and causes

Hypotension – Overview Low blood pressure might seem beneficial, and for some people, no problems are caused. However, for many people, abnormally low blood pressure also known as hypotension can cause dizziness and fainting. Low blood pressure can be life-threatening when the case is severe A blood pressure in which the reading lower than 90 […]

Hypotension – Overview

Low blood pressure might seem beneficial, and for some people, no problems are caused. However, for many people, abnormally low blood pressure also known as hypotension can cause dizziness and fainting. Low blood pressure can be life-threatening when the case is severe

A blood pressure in which the reading lower than 90 millimetres of mercury (mm Hg) for the top number (systolic) or 60 mm Hg for the bottom number (diastolic) is usually considered as low blood pressure.


From dehydration to serious medical disorders can be the causes of low blood pressure. It’s necessary to figure out what’s causing the low blood pressure so that it can be treated.


Hypotension – Symptoms

Low blood pressure signals for some people can be an underlying problem, especially when it drops suddenly or is accompanied by signs and symptoms such as:

  • Dizziness or lightheadedness
  • Fainting
  • Blurred or fading vision
  • Nausea
  • Fatigue
  • Lack of concentration


This life-threatening condition can be an outcome of extreme hypotension. Signs and symptoms may include:

  • Confusion, especially in older people
  • Cold, clammy, pale skin
  • Rapid, shallow breathing
  • Weak and rapid pulse

Doctor Consultation

Signs or symptoms of shock are being seen, seek emergency medical help.

If blood pressure readings is consistently low but feel fine, the doctor will likely just monitor during routine exams.

Occasionally a relatively minor problem can even be dizziness or lightheadedness, the outcome of mild dehydration from too much time in the sun or a hot tub as an example. Still, it’s necessary to see the doctor if having signs or symptoms of low blood pressure because they can point to more-critical problems. Keeping a record of symptoms can be helpful, when are they occurring and at what time.


During the active and resting phases of each heartbeat, blood pressure is a measurement of the strain in arteries

  • Systolic pressure is occurring when the top number in a blood pressure reading is the amount of pressure the heart produces when pumping blood through the arteries to the rest of your body.
  • Diastolic pressure is occurring when the bottom number in a blood pressure reading refers to the amount of pressure in the arteries when the heart is at rest between beats.

Recent guidelines identify normal blood pressure as lower than 120/80 mm Hg.

Blood pressure differs throughout the day, depending on:

  • Body position
  • Breathing rhythm
  • Stress level
  • Physical condition
  • Medications you take
  • What is eaten and drank
  • Time of day

Blood pressure is generally lowest at night and rises sharply on waking up.

Blood pressure: How low can be gone?

A low blood pressure for one can be a normal blood pressure for someone else. Blood pressure is considered too low by doctors only if it causes symptoms.

Some experts have define low blood pressure as readings which are lower than 90 mm Hg systolic or 60 mm Hg diastolic. If either of the number is below that, the pressure is lower than normal.

A sudden decrease in blood pressure can be dangerous. A change of just 20 mm Hg and a drop from 110 systolic to 90 mm Hg systolic, as an example, can be the cause of dizziness and fainting when the brain is not receiving enough blood. And big drops, such as those which are caused by uncontrolled bleeding, severe infections or allergic reactions, can be dangerous to the life.

Conditions causing low blood pressure

Medical conditions that can be a cause low blood pressure may include:

  • Pregnancy as the circulatory system expands rapidly during pregnancy, blood pressure is possibly to drop. This is normal, and blood pressure generally come backs to yhe pre-pregnancy level after given birth.
  • Some heart conditions that can caused low blood pressure include extremely low heart rate (bradycardia), heart valve problems, heart attack and heart failure.
  • Thyroid medical conditions such as parathyroid disease, adrenal insufficiency (Addison’s disease), low blood sugar (hypoglycemia) and, in some kf the cases, diabetes can be a trigger to low blood pressure.
  • When the body loses more water than it takes in that is dehydration, it can cause weakness, dizziness and fatigue. Fever, vomiting, severe diarrhea, overuse of diuretics and intense exercise can cause dehydration.
  • A lot of blood loss, such as from a major injury or internal bleeding, decreases the amount of blood in the body, leading to a severe drop in blood pressure.
  • When a severe infection in the body enters the bloodstream, it can lead to a life-threatening fall in blood pressure which is called septic shock.
  • Triggers which are common of this severe and potentially life-threatening reaction include foods, certain medications, insect venoms and latex. Anaphylaxis can cause problems such as breathing problems, hives, itching, a swollen throat and a dangerous drop in blood pressure.
  • A lack of the nutrients in the diet such as vitamin B-12, folate and iron can keep the body from developing enough red blood cells (anemia), causing low blood pressure.

Medications causing low blood pressure

Consuming some medications can cause low blood pressure, including:

  • Water pills (diuretics), such as furosemide (Lasix) and hydrochlorothiazide (Microzide, others)
  • Alpha blockers, such as prazosin (Minipress)
  • Beta blockers, such as atenolol (Tenormin) and propranolol (Inderal, Innopran XL, others)
  • Drugs for Parkinson’s disease, such as pramipexole (Mirapex) or those containing levodopa
  • Certain types of antidepressants (tricyclic antidepressants), including doxepin (Silenor) and imipramine (Tofranil)
  • Drugs for erectile dysfunction, including sildenafil (Revatio, Viagra) or tadalafil (Adcirca, Alyq, Cialis), particularly when taken with the heart medication nitroglycerin (Nitrostat, others)

Types – low blood pressure

Doctors often classify down low blood pressure (hypotension) into categories, depending on the causes and other factors. Some forms of low blood pressure include:

  • Low blood pressure when standing up (orthostatic or postural) hypotension).This causes a sudden drop in blood pressure when standing up from a sitting position or after lying down.

Blood starts to pool in the legs when standing caused by gravity. Typically, the body compensates by increasing the heart rate and constricting blood vessels, thereby making sure that enough blood returns to the brain.

But in people having orthostatic hypotension, this mechanism of compensating fails and blood pressure falls, leading to dizziness, lightheadedness, blurred vision and even fainting.

Orthostatic hypotension can happen for many reasons, including dehydration, prolonged bed rest, pregnancy, diabetes, heart problems, burns, excessive heat, large varicose veins and certain neurological disorders.

Orthostatic hypotension is especially found in older adults, but it also can affect the young, otherwise healthy people who stand up suddenly after sitting with their legs crossed for long periods or after squatting for a time.

  • Low blood pressure after eating (postprandial hypotension).This blood pressure drop happens one to two hours after eating and affects mostly adults who are older.

Blood flows to thr digestive tract after eating. Ordinarily, the body increases the heart rate and shrinks certain blood vessels to help in maintaining normal blood pressure. These fail in some people leading to dizziness, faintness and falls.

People with high blood pressure are most likely to be affected by Postprandial hypotension or autonomic nervous system disorders such as Parkinson’s disease.

For helping the symptoms to decrease eating small, low-carbohydrate meals; drink more water; and avoid alcohol

  • Low blood pressure due to faulty brain signals (neurally mediated hypotension).After standing for long periods the blood pressure drops is caused by this disorder, mostly affects young adults and children. It seems to happen because of a miscommunication between the heart and the brain.
  • Low blood pressure because of nervous system damage (multiple system atrophy with orthostatic hypotension).Also known as Shy-Drager syndrome is a rare disorder that has many symptoms like Parkinson disease. It causes progressive damage to the autonomic nervous system, through which involuntary functions are controlled such as blood pressure, heart rate, breathing and digestion. It’s related with having very high blood pressure while lying down.

Risk factors

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

  • Blood pressure dropping while standing or after eating happen primarily in adults aged older than 65. Neurally mediated hypotension affects usually children and younger adults.
  • People who consuming certain medications, for example, high blood pressure medications such as alpha blockers, have more risk of low blood pressure.
  • Certain diseases such as Parkinson’s disease, diabetes and some heart conditions can put at a greater risk of developing low blood pressure.


Types of low blood pressure which are moderate can cause dizziness, weakness, fainting and a risk of injury from falls.

Blood pressure being severely low can deprive the body of enough oxygen to carry out its functions, leading to damaging the heart and brain.


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