Causes And Symptoms Of Low Blood Pressure

Low blood pressure (hypotension, arterial hypotension) is defined as blood pressure below 90/60 mm Hg. The number 90 here refers to the upper (systolic) pressure, and the number 60 to the lower (diastolic) pressure. Arterial hypotension is a pathological decrease in blood pressure (BP) less than 100/60 mm Hg, accompanied by dizziness, impaired vision, decreased thinking ability, and fainting.

Low BP can vary quite widely from person to person. Low blood pressure readings do not always indicate a health risk. Many people with low blood pressure feel fine and do not feel any symptoms, this is their norm, which in no way affects the quality of life and does not indicate the development of any pathology.

Causes And Symptoms Of Low Blood Pressure

Symptoms Of A Decrease In Blood Pressure:

To reduce the severity of symptoms, the doctor may recommend drinking more fluids, gently getting up from a sitting or lying position, avoiding situations requiring prolonged standing (in case of nerve-mediated hypotension), refusing alcohol, wear compression knitwear.

Symptoms of low blood pressure are:

  • Weakness
  • Dizziness
  • Nausea
  • Vomiting
  • Loss of consciousness;
  • Impaired coordination of movement;
  • Pale skin
  • Slowing or rapid pulse

Possible Causes Of Decreased Blood Pressure

To understand the cause of a decrease in BP, it is necessary to determine the timing of the development of hypotension.

If the pressure falls sharply, then the cause may be acute heart failure, severe bleeding, infectious process, toxic syndrome, high fever, dehydration, or overdose of some drugs.

A pronounced decrease in blood pressure is one of the main symptoms of developing shock. This condition is accompanied by disorders of tissue blood circulation and leads to irreversible consequences. Shock can be:

Hypovolemic – as a result of massive blood loss, burns, dehydration

Circulatory – Includes anaphylactic shock (as a result of an allergic reaction to the effect of a substance) and infectious-toxic shock (in poisoning, infection, and intoxication);

Cardiogenic – in acute cardiac disorders (most often in myocardial infarction).

Other Causes Of Low Blood Pressure include:

  • Alcohol abuse;
  • Anti-anxiety medications, tricyclic antidepressants, diuretics, medications to treat cardiovascular disease (including arterial hypertension and coronary heart disease), Parkinson’s disease, erectile dysfunction, and pain medications;
  • Dehydration;
  • Pregnancy (especially before 24 weeks);
  • Heart failure, heart attack, bradycardia, arrhythmias, pneumothorax, pulmonary embolism;
  • Diabetes mellitus, hypoglycemia, hypothyroidism, parathyroid disease, Addison’s disease, multiple system atrophy;
  • create deficiency of iron, folic acid and vitamin B12.

Causes Of Chronic Lowering Of Blood Pressure:

Chronic lowering of blood pressure is possible in the following diseases:

  • Diabetic neuropathy
  • Hypothyroidism
  • Chronic adrenal insufficiency
  • Head injuries (concussion, contusions
  • Anemia
  • Stroke
  • Brain tumours
  • Toxic exposure (occupational hazards)
  • Neurosyphilis
  • Amyotrophic lateral sclerosis, etc.

What is The Danger of Low Blood Pressure?

  • Low blood pressure is dangerous if accompanied by noticeable signs and symptoms. These include dizziness, rapid shallow breathing, sticky sweat, pallor of the skin, nausea, dehydration, severe thirst, decreased concentration, blurred vision, fainting, weakness, fatigue, and depression.
  • If the patient suffers from chronic adrenal insufficiency, then as a result of a deficiency of the hormones aldosterone and cortisol, there is a loss of sodium and potassium retention in the body, which leads to dehydration and impaired cardiovascular function. One of the symptoms may be a decrease in blood pressure.

Types Of Hypotension:

1. Postprandial Hypotension:

With postprandial hypotension, blood pressure drops 1-2 hours after eating (after eating, blood rushes to the GI tract, and there is vasoconstriction, which increases HR). Most often, hypotension of this type affects the elderly, especially if they have diseases of the central nervous system (Parkinson’s disease) or arterial hypertension. To reduce the risk of sudden drops in BP, such patients are recommended to eat small meals, reduce the amount of carbohydrates in their diet, drink enough water, and avoid alcoholic beverages.

2. Physiologic Hypotension:

Hypotension is considered pathological when physical activity, work capacity, and other symptoms of disadvantage are reduced. In practice, a distinction is made between acute and chronic decrease in blood pressure.

 The blood pressure of a healthy person at rest is below 100/60 mm Hg. It occurs as an individual variant of the norm, in athletes, residents of high mountains, tropics, and polar regions (adaptive or compensatory hypotension).

3. Orthostatic Hypotension:

Orthostatic hypotension is a decrease in systolic (upper) blood pressure by 10 mm Hg or more in combination with an increase in heart rate by 10 beats per minute or more when the patient moves from lying to sitting or standing. The described changes should persist for at least two minutes after the change of body position.

(symptoms of hypotension last from a few seconds to a few minutes) occurs with a sudden change in body position (getting up from sitting or lying down), often occurs in the elderly, but can be observed with prolonged bed rest, dehydration, pregnant women, and people with chronic diseases (diabetes mellitus).

4. Medication-Induced Hypotension:

Medication-induced hypotension is a decrease in blood pressure due to the use of blood pressure-lowering medications.

These include the following groups of drugs:

Nitrates (Nitroglycerin);

  • Angiotensin-converting enzyme (ACE) inhibitors – captopril, enalapril, perindopril, and others;
  • Slow calcium channel blockers (nifedipine, verapamil, diltiazem, etc.);
  • Beta-Adreno blockers (metoprolol, bisoprolol, etc.);
  • Diuretics, or diuretics (furosemide, spironolactone, hydrochlorothiazide, etc.).
  • Attention should be paid when the upper (systolic) pressure is normal or elevated, and the lower (diastolic) pressure is decreased. This situation may be a symptom of a heart defect – aortic valve insufficiency and requires consultation with a cardiologist and cardiac surgeon.

5. Neurogenic Lowering Of Blood Pressure:

Neurogenic lowering of blood pressure is more common in adolescence and young adulthood. This type of hypotension is the result of a functional disorder of the nervous system or organic brain damage.

A sudden and severe drop in blood pressure (caused by severe and uncontrolled bleeding, severe infections, allergic reactions, burns, and heart attack) can be life-threatening and require emergency care.

 Causes of organic brain damage can be:

  • Trauma (concussions or contusions of the brain);
  • Degenerative changes in the substance of the brain (changes in the structure of neuronal membranes, destruction of neurons);
  • Disorders of cerebral circulation (heart attacks, strokes);
  • Violation of the release of catecholamines (adrenaline, noradrenaline) – physiologically active substances – into the blood during physical activity.

What Diseases Cause Low Blood Pressure?

A sudden drop in blood pressure is characteristic of:

  • Myocardial infarction
  • Severe heart rhythm disorders (arrhythmias)
  • Intracardiac blockages
  • Pulmonary embolism
  • Massive blood loss
  • Allergic reactions
  • Burns

What Doctors Should Be Consulted In Case Of A Decrease In Blood Pressure?

Patients suffering from arterial hypotension should be examined by different specialists:

  • Cardiologist
  • General practitioner
  • Endocrinologist
  • Neurologist
  • Surgeon

Diagnosis And Examination:

With low blood pressure, consult a specialist.

The doctor, if necessary, will prescribe tests:

  • Clinical blood test – to detect possible anaemia and infectious process.
  • General urinalysis – to assess the work of the kidneys.
  • Biochemical blood test (control of cholesterol levels, very low-, low- and high-density lipoproteins to assess the risk of atherosclerosis, blood electrolytes – potassium, sodium, calcium, creatinine levels).
  • Blood tests for the content of hormones (thyroxine – T4, triiodothyronine – T3, thyroid hormone – TTG), antibodies to thyroperoxidase, and antibodies to thyroglobulin.


The method of treatment directly depends on the cause of hypotension. With an allergic reaction, treatment is applied, aimed at eliminating the allergen, relieving swelling, and increasing blood pressure. If a myocardial infarction is suspected, the patient can be given an aspirin tablet and called an ambulance. If the decrease in blood pressure is accompanied by neurogenic signs: weakness in the arms and legs, speech, vision, and facial asymmetry, it is necessary to lay the patient on his side and call an ambulance.5

As part of self-help in the presence of precursors of fainting (weakness, dizziness, tinnitus, darkening of the eyes), it is necessary as soon as possible to sit on a chair or the floor, lower the heat, steady and deep breathing. It is important to remember that falling from your height can cause serious injury.


It should be understood that low blood pressure occurs when the mechanisms of its regulation are disturbed. Chronic hypotension can lead to a decrease in the activity of endocrine glands. For example, in hypothyroidism, metabolism changes, in particular, proteins and electrolytes, which leads to redistribution of fluid in the body and changes in blood pressure. Also in hypothyroidism, the development of arterial hypotension is a consequence of bradycardia (slowing of the pulse).


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