Hypotention: definition

The voltage or arterial pressure is the force exerted by the blood on the wall of the arteries. THE’arterial hypotension is characterized by a blood pressure abnormally low. 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. There are many causes of hypotension: neurological problem, side effect of a drug, dehydration, etc.

The sudden drop in blood pressure may be accompanied bydizziness and weakness for a few seconds, and sometimes for a fainting. These symptoms usually appear after getting up quickly from a chair or bed. Like the heart rate or body temperature, pressure must be kept at a relatively constant level to keep the body functioning properly.

People of all ages can have symptoms of hypotension occasionally, including healthy young adults. However, people over 65 are the ones who suffer most from it. 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 (s). Bedridden people and pregnant women are also more prone to it.

Blood pressure

La blood pressure (or blood pressure) consists of systolic and diastolic pressures, which are measured in millimeters of mercury, or mmHg. Pressure systolic is the pressure of the blood when the heart contracts and sends blood through the arteries. It ensures a supply of blood throughout the body. Pressure diastolic is the one that continues to exert itself on the arteries between each contraction as the heart fills with blood again. So, when we talk about a 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 slightly lower blood pressure than normal. This is generally the case with athletes and people who train regularly. We see the sign of a 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 the dizziness and fainting.

Blood pressure is controlled by multiple mechanisms, governed by the “autonomic” nervous system (which we do not consciously control). Normally, the pressure drops, which occur for example when one goes from sitting to standing, are corrected quickly 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).

Types d’hypotension

There are various forms of hypotension, the causes and symptoms of which vary. here is 2 common forms transient and unsupported hypotension more affecting the elderly population.

Hypotension orthostatique ou postural

Symptoms of this type of hypotension arise after a lever trop to Apply from bed, chair, squatting or leaning. Under the sudden effect of gravity, the amount of blood reaching the brain temporarily decreases. This leads to dizziness, visual disturbances, 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 over 75¹.

Most of the time, there is no obvious cause and these are trivial cases. When hypotension is frequent, it is necessary to consult a doctor. It may be a neurological problem that disrupts the regulation of the nervous system that controls blood pressure. In older people, however, the most common cause is taking medication. Here are the most common causes of orthostatic hypotension.

• A Dehydration (associated or not with fever). Seniors feel less thirsty and are therefore more prone to dehydration.
• Taking some pharmaceuticals, such as those used to treat hypertension or erectile dysfunction, antidepressants, anxiolytics and neuroleptics, nitroglycerin (and nitrates), diuretics and other medicines to treat heart failure.
• The consumption of marijuana or alcohol.
• After one prolonged immobilization in bed, physical deconditioning or significant weight loss.
• Un heart or blood vessel disorder : 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.
• Stroke and other degenerative diseases affecting the autonomic nervous system.
• Insufficiency of the adrenal gland.
• Abrupt withdrawal from 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 the onset of meal, causing dizziness, nausea, fainting or falling. After each meal, the process of digestion causes a rush of blood to the stomach and intestines; which may cause a slight decrease in blood pressure. In the elderly or debilitated by the disease, this slight pressure drop is enough to trigger symptoms of hypotension. Symptoms appear 15 minutes to 2 hours after a meal.

Postprandial hypotension is more common in diabetes, heart or kidney failure, or Parkinson’s disease. It mainly affects older people who also have high blood pressure².

Let us mention that a hypotension grave may occur with blood loss (hemorrhage) severe, anaphylactic shock or generalized infection (sepsis). These situations require emergency medical care.

Diagnose hypotension

Unlike hypertension, there is no threshold value that defines thehypotension. If there are no symptoms, the lower the blood pressure, the better the cardiovascular health. To make his diagnosis, the doctor mainly bases himself on the symptoms. However, these usually appear when the systolic pressure is below 100 or 90 mmHg (millimeters of mercury). Evidence of orthostatic hypotension can be obtained if, on passing rapidly from lying position to the standing position, the pressure drops by more than 20 mmHg systolic on 10 mmHg diastolic. As for postprandial hypotension, it is generally defined by a drop in systolic blood pressure of at least 20 mmHg when lying down within 2 hours of starting a meal.².

When to consult

Most of the time, occasional periods ofhypotension are not serious and do not require consultation with a doctor. However, if they are very frequent, if the symptoms are bothersome or if the pressure still remains levels too low (

Symptoms of the disease

• Dizziness
• A feeling of weakness
• A blurred vision
• Nausea
• Increased heart rate
• Fainting or fainting