Hypotension: definition, symptom, treatment
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Do you ever feel weak and dizzy?

You may be suffering from low blood pressure.

What is hypotension? What are its symptoms and the different types of hypotension?

All the answers can be found in this sheet.

Hypotension: definition

Tension or arterial pressure is the force exerted by the blood on the walls of the arteries. Arterial hypotension is characterized by abnormally low blood pressure. It is, in a way, the reverse of hypertension.

This low pressure can be permanent or transient, occasional or frequent. It is not a disease as such, but rather a symptom.

The causes of hypotension are multiple: neurological problems, side effects of a drug, dehydration, etc.

The sudden drop in blood pressure may be accompanied by dizziness and weakness for a few seconds, and sometimes fainting. These symptoms usually appear after getting up quickly from a chair or bed. 

Like heart rate or body temperature, pressure must be maintained at a relatively constant level for the body to function properly.

People of all ages can have symptoms of low blood pressure occasionally, including healthy young adults. People over the age of 65 are nevertheless those who suffer from it most often. 

In 20% of them, the phenomenon occurs regularly and can have several causes. It is therefore important to consult a doctor in order to find the cause or causes. Bedridden people and pregnant women are also more prone to it.

blood pressure

Blood pressure (or blood pressure) is made up of systolic and diastolic pressures, which are measured in millimeters of mercury, or mm Hg.

Systolic pressure is the blood pressure when the heart contracts and pushes blood through the arteries. It ensures blood supply throughout the body.

Diastolic pressure is the pressure that continues to exert on the arteries between each contraction as the heart refills with blood. So, when we talk about the pressure of 120/80, 120 corresponds to the systolic pressure, and 80 to the diastolic pressure.

The pressure is considered normal if it is less than or equal to 120/80 or 115/75, depending on the country. However, blood pressure numbers vary a lot from person to person, as well as throughout the day depending on activities. 

At rest, many healthy people have a slightly lower blood pressure than normal. This is usually the case with athletes and people who train regularly. It is seen as a sign of good cardiovascular health. Thus, it is generally considered that the lower the pressure, the better.

However, below a certain limit, the pressure is too low to properly propel blood through all blood vessels. This has the consequence of not sufficiently oxygenating certain parts of the body, in particular the brain. This is what causes dizziness and fainting.

Blood pressure is controlled by multiple mechanisms, governed by the “autonomic” nervous system (which we do not consciously control). 

Normally, pressure drops, which occur for example when going from sitting to standing, are quickly corrected by reflex reactions (increased heart rate, narrowing of the opening of small blood vessels, etc.). 

For these reactions to take place, the drop in pressure must first have been detected by blood pressure sensors housed in the walls of the arteries, called baroreceptors (see diagram).

The different types of hypotension

There are various forms of hypotension, the causes, and symptoms of which vary. Here are 2 frequent forms of transient and unsustained hypotension affecting more the elderly population.

Orthostatic or postural hypotension

Symptoms of this type of hypotension arise after getting up too quickly from bed, from a chair, or from a squatting or bending position. Under the sudden effect of gravity, the amount of blood reaching the brain temporarily decreases. This leads to dizziness, visual disturbances, and sometimes even a fall.

Orthostatic hypotension is common in the elderly. While it is found in 5% to 10% of the general population, it affects 15% of people over 65 and 30% of people over 75.

Most of the time, there is no obvious cause and these are innocuous cases. When hypotension is frequent, it is necessary to consult a doctor. 

It may be a neurological problem disrupting the regulation of the nervous system that controls blood pressure. In the elderly, however, the most common cause is taking medication.

Here are the most common causes of orthostatic hypotension:

  • dehydration (whether or not associated with fever). Seniors feel less thirsty and are therefore more prone to dehydration;
  • taking certain medicines, such as those used to treat high blood pressure or erectile dysfunction, antidepressants, anti-anxiety and neuroleptics, nitroglycerin (and nitrates), diuretics, and other medicines to treat heart failure;
  • the use of marijuana or alcohol;
  • after prolonged immobilization in bed, physical deconditioning, or significant weight loss;
  • a disorder of the heart or blood vessels: heart disorder, myocardial infarction, heart failure, large and numerous varicose veins;
  • diabetes, which can damage the nervous system;
  • a disease that affects the nervous system, such as Parkinson’s disease, multiple sclerosis, Guillain Barré syndrome, etc. ;
  • strokes and other degenerative diseases affecting the autonomic nervous system;
  • insufficiency of the adrenal gland;
  • abrupt withdrawal of corticosteroid therapy (cortisone) taken for a very long time.

Hypotension postprandiale

It is characterized by a significant drop in blood pressure within 2 hours of starting a meal, causing dizziness, nausea, fainting, or falling.

After each meal, the process of digestion causes blood to flow to the stomach and intestines; which may cause a slight decrease in blood pressure. 

In the elderly or debilitated by disease, this slight drop in pressure is enough to trigger symptoms of hypotension. Symptoms appear 15 minutes to 2 hours after eating.

Postprandial hypotension is more common in diabetes, heart or kidney failure, or Parkinson’s disease. It mainly affects the elderly who also suffer from high blood pressure.

Note that severe hypotension can occur in the event of significant blood loss (hemorrhage), anaphylactic shock, or generalized infection (sepsis). These situations require emergency medical attention.

How to diagnose hypotension?

Unlike hypertension, there is no threshold value that defines hypotension. If there are no symptoms, the lower the blood pressure, the better the cardiovascular health.

To make a diagnosis, the doctor bases himself mainly on the symptoms. That said, these usually appear when the systolic pressure is below 100 or 90 mmHg (millimeters of mercury). 

Evidence of orthostatic hypotension may be obtained if, on the rapid transition from a supine to a standing position, the pressure drops more than 20 mmHg systolic to 10 mmHg diastolic.

Postprandial hypotension is generally defined by a drop in systolic blood pressure of at least 20 mmHg in the supine position within 2 hours of the start of a meal.

When to consult a doctor ?

Most of the time, occasional periods of low blood pressure are not serious and do not require medical attention.

However, if they are very frequent, if the symptoms are bothersome, or if the pressure always remains at too low levels (< 90 mmHg), it is better to consult.

Symptoms of hypotension

Here is a detailed list of symptoms caused by low blood pressure:

  • dizziness;
  • a feeling of weakness;
  • blurred vision;
  • nausea ; 
  • rapid heartbeat;
  • fainting or fainting.

People at risk of hypotension

Several types of people are particularly vulnerable to hypotension:

Old people

With age, the walls of the blood vessels become more rigid, and the baroreceptors, are less sensitive to pressure variations in the arteries.

Pregnant women

It is normal for blood pressure to drop during pregnancy, even though the overall blood volume increases. Certain hormonal factors cause relaxation of the muscles of the arterial and venous walls, which can lead to transient hypotension.

People with heart problems

Numerous heart attacks or diffuse diseases of the heart muscle (cardiomyopathy, myocarditis) can prevent the heart from pumping blood at sufficient pressure.

People with significant varicose veins

Indeed, it is possible that a large amount of blood can stagnate in the varicose veins.


People with diabetes that has caused complications of the autonomic nervous system.

People with diseases that affect the nervous system

Like Parkinson’s disease, Guillain-Barré syndrome (rare acute neuropathy), multiple sclerosis, and Shy-Drager disease (a rare neurodegenerative disease), or have suffered from strokes.


People with adrenal gland insufficiency or who have abruptly stopped prolonged cortisone treatment.

Risk factors for hypotension

Do you know the risk factors for hypotension?

Here they are :

Consuming alcohol and/or cannabis

Consuming alcohol increases the risk of hypotension in people who are already debilitated. Alcohol dilates blood vessels and causes urination, which causes dehydration and lowers blood pressure.

The hypotensive effects of alcohol and cannabis (marijuana) can add up and cause severe and prolonged hypotension in some people.

Taking certain medications

Many drugs can cause hypotension, including antihypertensives, diuretics, vasodilators, neuroleptics, anxiolytics, hypnotics, antidepressants, and nitrates.

Basic preventive measures, implemented in your daily life, can help you reduce the risk of hypotension.

Discover them in detail in this sheet.

Basic preventive measures to combat hypotension

In the case of orthostatic hypotension

  • Get up slowly. Before getting out of bed, stretch then sit on the edge of the bed for 1 minute;
  • drink water and other beverages regularly. In hot weather, people taking diuretics and limiting salt intake, water, and salt intake can prevent hypotension. Seek advice from a doctor or pharmacist;
  • avoid alcohol consumption. Even consumed in moderation, it can contribute to hypotension;
  • avoid using cannabis (marijuana);
  • avoid hot environments. Heat dilates blood vessels and increases sweating, which can cause a slight drop in blood pressure;
  • eat slightly saltier food. This may help people who normally avoid the salt shaker, but it is not a general recommendation. Salt causes water retention. Consult a doctor before increasing your salt intake;
  • leave the legs uncrossed. In a seated position, crossing the legs puts pressure on the veins and forces the blood to remain in the lower body;
  • if necessary, wear compression stockings;
  • avoid physical exertion when it is too hot;
  • quickly drink 500 ml of cold water to increase blood volume, when a long period of standing is necessary (shopping, for example) 5 ;
  • in case of heart problems or hypertension, see your doctor regularly so that he can properly adapt the dosage of the treatment.
  • if you suspect that taking any medication is causing low blood pressure, talk to your doctor.

In case of postprandial hypotension

  • Do not drink alcohol before and after meals;
  • avoid overly large meals: favor lighter and more frequent meals, not too rich in sugar;
  • a walk after the meal can help, but it is better to avoid physical exertion.
Note: Drinking coffee or tea after a meal alleviates postprandial hypotension because caffeine raises blood pressure. However, it is recommended not to increase your coffee consumption without first talking to your doctor.

Low blood pressure that causes no symptoms or produces brief, infrequent bouts of dizziness when standing up usually does not require treatment.

Treatment for hypotension greatly depends on the underlying cause. Changing lifestyle habits is most of the time sufficient (see Prevention section).

Medical treatments for hypotension

When low blood pressure is constant and associated with taking medication, the doctor will probably advise you to stop or reduce the medication.

When orthostatic hypotension significantly reduces the quality of life, and precautionary measures fail to reduce symptoms, medications can be prescribed. They act either on the nervous system or on the control of blood volume3.

The drug most often prescribed is fludrocortisone (Florinef): which causes an increase in blood volume.

Midodrine can also be used 30 minutes before getting up, for example, then at 2 or 3 times during the day.

In case of mild hypotension, pyridostigmine may also be prescribed.

Also, drugs that slow stomach emptying (eg, acarbose) can help treat postprandial hypotension in people with diabetes.

In all cases, close monitoring must be carried out by the doctor to avoid sudden increases in blood pressure.

As a last resort, fitting an electrosystolic trainer (pacemaker) can help with treatment by increasing the baseline heart rate.

What to do if someone close to you faints?

Lay the person down and raise their feet to bring the blood to their brain. If the fainting is due to a hypotensive crisis, the person will regain consciousness immediately. If the person does not regain consciousness quickly, call the emergency services.

In parallel with medical treatments, it is sometimes possible to use complementary approaches to treat the disease.

Are there approaches to treat hypotension?

Hypotension: complementary approaches

Based on our research, there is no complementary approach to treat hypotension.

However, Traditional Chinese Medicine considers that it can be treated with acupuncture or herbal remedies. Regular physical activity (not involving sudden movements) can help alleviate symptoms by increasing blood volume.

Warning: some medicinal plants can cause a drop in blood pressure. Some of these include cat’s claw, mistletoe, stevia, and Yohimbe. Ask a healthcare professional if you have low blood pressure and are using any of these products. Using quercetin or N-acetylcysteine ​​supplements (in conjunction with nitroglycerin) in high doses can also lower blood pressure.

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