Voltage or high blood pressure is the force exerted by the blood on the walls of arteries. The blood pressure is characterized by a blood pressure abnormally low. It is, in a way, the opposite of hypertension. This low pressure can be permanent or transient, occasional or frequent. It is not an illness as such, but rather a symptom. The causes of hypotension are multiple: neurological problem, side effect 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, the pressure must be kept relatively constant to ensure proper functioning of the body.
People of all ages may have occasional symptoms of hypotension, including healthy young adults. People over the age of 65 are, however, those who suffer most often. In 20% of them, the phenomenon occurs regularly and can have several causes. It is important to consult a doctor to find the cause or causes. Bedridden people and pregnant women are also more prone to it.
The blood pressure (or blood pressure) consists of systolic and diastolic pressures, which are measured in millimeters of mercury, or mmHg. The systolic pressure is the pressure of the blood when the heart contracts and sends the blood into the arteries. It ensures blood supply throughout the body. The diastolic pressure is the one that continues to be exerted on the arteries between each contraction at the moment when the heart fills with blood again. Thus, when one speaks of a pressure of 120/80, 120 correspond 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 figures vary greatly from person to person, as well as during the day depending on the activity. At rest, many healthy people have slightly lower blood pressure than normal. This is generally the case for athletes and people who train regularly. This is 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 propel the blood properly into all the blood vessels. This has the effect of not oxygenating enough parts of the body, especially the brain. This causes vertigo and fainting.
Blood pressure is controlled by multiple mechanisms, governed by the autonomic nervous system (which is not controlled consciously). Normally, pressure drops, for example when moving from sitting to standing, are rapidly corrected by reflex reactions (increased heart rate, narrowing of the opening of small blood vessels, etc.). For these reactions to take place, the pressure drop must first have been detected by blood pressure sensors housed in the artery walls, called baroreceptors (see diagram).
Types of hypotension
There are various forms of hypotension, the causes and symptoms of which vary. Here are 2 common forms of transient and unsupported hypotension that affect the older population more.
Orthostatic or postural hypotension
The symptoms of this type of hypotension arise after a too fast lifting of the bed, a chair, 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, 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 those over 75.
Most of the time, there is no obvious cause and these are trivial cases. When hypotension is common, it is necessary to consult a doctor. It can 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 a medication. Here are the most common causes of orthostatic hypotension.
- Dehydration (with or without fever). Seniors feel less thirsty and are therefore more prone to dehydration.
- Taking certain medications , such as those used to treat high blood pressure or erectile dysfunction, antidepressants, anxiolytics 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 trouble, myocardial infarction, heart failure, wide varicose veins and many.
- 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.
- Of stroke and other degenerative diseases of the autonomic nervous system.
- An insufficiency of the adrenal gland.
- Abrupt withdrawal of a corticosteroid (cortisone) taken for a very long time.
It is characterized by a significant drop in blood pressure within 2 hours after the start of the meal, causing dizziness, nausea, fainting or falling. After each meal, the process of digestion causes an influx of blood to the stomach and intestines; this may result in a slight decrease in blood pressure. In the elderly or weakened by the disease, this slight drop in pressure is enough to trigger symptoms of hypotension. Symptoms appear from 15 minutes to 2 hours after the meal.
Postprandial hypotension is more common in diabetes, heart or kidney failure or Parkinson’s disease. It mainly affects the elderly with hypertension also.
It should be noted that severe hypotension may occur in the event of significant blood loss (haemorrhage), anaphylactic shock or generalized infection (sepsis). These situations require emergency medical care.
Diagnose of 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 relies heavily on the symptoms. However, these usually occur when the systolic pressure is below 100 or 90 mmHg (millimeters of mercury). A proof of orthostatic hypotension can be obtained if, by rapidly passing from the supine position to the upright position, the pressure drops more than 20 mmHg systolic 10 mmHg diastolic. As for postprandial hypotension, it is generally defined by a decrease in systolic blood pressure of at least 20 mmHg while lying in the 2 hours following the start of a meal.
When to consult
Most of the time, occasional periods of low blood pressure are not serious and do not require consultation with a doctor. However, if they are very frequent, if the symptoms are troublesome or if the pressure remains always at too low levels (<90 mmHg), it is better to consult.
- A feeling of weakness
- A tangled vision
- An acceleration of the heart rate
- Fainting or fainting
Symptoms of hypotension
- A feeling of weakness
- A tangled vision
- An acceleration of the heart rate
- Fainting or fainting
People at risk
- Old people. With age, the walls of the blood vessels become more rigid, and the baroreceptors less sensitive to pressure variations in the arteries.
- Pregnant women. It is normal for blood pressure to drop during pregnancy, even if the overall blood volume increases. Some hormonal factors cause a loosening of the muscles of the arterial and venous walls, which can lead to transient hypotension.
- People suffering from heart problems. Many infarcts or diffuse heart muscle disease (cardiomyopathy, myocarditis) can prevent the heart from propelling the blood to sufficient pressure.
- People with large varicose veins because a large amount of blood can stagnate in varicose veins.
- People with diabetes leading to complications of the autonomic nervous system.
- People suffering from diseases that affect the nervous system , such as Parkinson’s disease, Guillain-Barré syndrome (rare acute neuropathy), multiple sclerosis and Shy-Drager disease (rare neurodegenerative disease), or who have suffered ‘stroke.
- Sufferers of the adrenal gland or who have stopped abruptly prolonged cortisone treatment.
- Consuming alcohol increases the risk of hypotension in people who are already weak. Alcohol dilates the blood vessels and makes you urinate, 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.
- Many medications can cause hypotension, including antihypertensives, diuretics, vasodilators, neuroleptics, anxiolytics, hypnotics, antidepressants, and nitrates.
Prevention of hypotension
|Basic preventive measures|
|In case of orthostatic hypotension
In case of postprandial hypotension
Note. Drinking coffee or tea at the end of a meal alleviates postprandial hypotension, as caffeine increases blood pressure. However, it is recommended that you do not increase your coffee intake without talking to your doctor first.
Medical treatments for hypotension
A low blood pressure that does not cause symptoms or produces brief moments and infrequent dizziness when getting up usually does not require treatment.
The treatment of hypotension greatly depends on the underlying cause. Changing lifestyle habits is usually enough (see Prevention section).
When hypotension is constant and associated with medication, your doctor may advise you to stop or reduce medication.
When orthostatic hypotension significantly reduces quality of life and precautionary measures do not reduce symptoms, medications may be prescribed. They act either on the nervous system or on the control of blood volume.
The most commonly prescribed medication is fludrocortisone (Florinef): it causes an increase in blood volume. Midodrine can also be used 30 minutes before sunrise, for example, and then at 2 or 3 times of the day. In mild hypotension, pyridostigmine may also be prescribed. In addition, medications that slow stomach emptying (for example, acarbose) can help treat post-meal hypotension in people with diabetes. In all cases, close supervision should be done by the doctor to avoid sudden increases in blood pressure. As a last resort, placement of a pacemaker may help with treatment by increasing the baseline heart rate.
|What to do if one of your loved ones faints?
Lay the person down and lift their feet to bring the blood to their brain. If the fainting is due to a hypotension crisis, the person will immediately regain consciousness. If the person does not regain consciousness quickly, call for emergency assistance.