At a Glance :
- Low blood pressure is referred to as hypotension, and is diagnosed when blood pressure is around 90/60 mm Hg
- Typical symptoms of hypotension include blurred vision, dizziness, lightheadedness, fatigue and nausea. Severe hypotension is potentially life-threatening
- Low blood pressure may be classified in a number of different ways due to the underlying cause or the manner in which the symptoms prevent
- Orthostatic Hypotension symptoms occur when a person transitions from a sitting or prone position to standing
- Postprandial Hypotension symptoms occur an hour or two after eating
- Neurally Mediated Hypotension symptoms occur after a person has been standing for a long period of time and mostly affects children and young adults
- Multiple System Atrophy with Orthostatic Hypotension is causes by progressive autonomic nerve damage
- Hypotension may be caused by a number of factors including infection, disease, blood loss, dehydration, pregnancy and more
- Treatment for low blood pressure varies depending on the severity of symptoms and the underlying causes of the condition
What is Hypotension?
Low blood pressure is referred to as hypotension, and is diagnosed when blood pressure is around 90/60 mm Hg or lower. While having low blood pressure may seem desirable given the danger of high blood pressure, low blood pressure may also be a serious threat to health due to the fact that not enough oxygen and other vital nutrients is being delivered around the body as the result of hypotension.
Unlike hypertension , people with low blood pressure may display a number of symptoms, including:
- Blurred vision
- Concentration Problems
- Dizziness
- Fainting
- Fatigue - Nausea
Extremely low blood pressure is sometimes referred to as shock. Symptoms of shock may include a weak and rapid pulse, cold, pale and clammy skin, shallow breathing or panting and confusion.
Depending on the cause or trigger of hypotension it may be classified in a number of ways:
- Orthostatic Hypotension - the most common form of low blood pressure, affecting people of all ages, orthostatic hypotension occurs when a person transitions from sitting or lying down to standing.When you stand, gravity causes blood to pool in the legs. Typically the body will compensate for this by raising heart rate and constricting blood vessels to force this pooling blood back towards the brain. Orthostatic hypotension occurs when this typical response fails and blood is slow to return to the brain.
- Multiple System Atrophy with Orthostatic Hypotension - also referred to Shy-Drager Syndrome, this rare form of hypotension occurs due to progressive, Parkinson’s-like autonomic nerve damage affects the function of the heart, blood vessels, breathing and digestion.
An associated feature of Multiple System Atrophy with Orthostatic Hypotension is high blood pressure (hypertension) while lying down.
- Neurally Mediated Hypotension - low blood pressure that occurs after standing for long periods of time. Neurally Mediated Hypotension occurs more often in children than adults and appears to be caused by a miscommunication between the brain and the heart.
- Postprandial Hypotension - a drop in blood pressure that typically occurs within one to two hours after eating. While digesting, the body channels more blood flow to the digestive tract and typically compensates by increasing heart rate and constricting selected blood vessels so the rest of the body may be supplied with blood and nutrients.
Postprandial hypotension occurs when these compensatory mechanisms fail, leading to lightheadedness and loss of balance. It’s most common in people with high blood pressure and autonomic nervous system diseases such as Parkinson’s.
What Causes Hypotension?
In normal circumstances, everyone’s blood pressure will rise and fall during the day, with most people experiencing periods of high and low blood pressure. These brief periods are typically asymptomatic and resolve quickly. When low blood pressure persists for an extended period of time it may become dangerous.
There are many possible causes of or risk factors for hypotension, including:
- Age - Neurally Mediated Hypotension is more common in children and young adults. Postprandial Hypotension is more common in people over the age of 65
- Anaemia - anaemia is caused by a lack of iron in the blood making it more difficult for blood to be oxygenated. People with anaemia are at greater risk of experiencing orthostatic hypotension
- Anaphylactic Shock - anaphylaxis is the most severe form of allergic reaction. Allergic reactions occur when a person’s immune system is triggered to act by a substance that other people may find harmless, such as peanuts or strawberries.
When responding to an allergen, the immune system responds by flooding the body with antibodies as well as causing cells to release huge amounts of stored chemicals known as histamines. These chemicals cause blood vessels to widen so more antibody filled blood can reach the source of “infection”.
During anaphylaxis, the flood of histamines may cause a rapid and dangerous drop in blood pressure
- Blood Loss - hypovolemia is a decrease in blood volume. As the body loses blood, through external wounds or internal bleeding such as may be experienced with a perforated stomach ulcer, heart rate typically increases to try and compensate for the reduced volume and pressure of blood.
Hypotension due to blood loss becomes much more severe depending on the amount of blood lost. Blood loss under 15% of total volume typically only results in a minimal increase of heart rate and drop in pressure. Between 15% and 40% the increase in heart rate and fall in blood pressure is much more severe but treatable through increasing blood volume.
Blood loss of greater than 40% of total is life threatening and requires immediate treatment to prevent organ damage, failure or death.
- Dehydration - dehydration, caused by factors such as fever, diarrhea, vomiting, strenuous exercise, overuse of diuretics and more, lead to a reduction in blood volume which may in turn cause hypotension
- Endocrine Disorders - diseases and disorders such as diabetes, thyroid disorders and adrenal insufficiency may all lead to hypotension
- Heart Conditions - a number of different heart disorders can make it difficult for the heart to deliver vital nutrients around the body and may lead to low blood pressure, including an abnormally low heart rate (brachycardia), heart failure, heart attack and problems with heart valves (both cause by disease and congenital defects)
- Medications - a number of medications may lead to low blood pressure through a variety of mechanisms. Diuretic medications frequently prescribed to combat hypertension may reduce blood volume leading to hypotension. Similarly, though through different means, other hypertension drugs may result in hypotension if overused or used improperly.
Other medications that may lead to hypotension include beta blockers used to treat heart conditions, a number of medications used in the treatment of Parkinson’s disease, tricyclic antidepressants and erectile dysfunction drugs.
- Nutrition - a lack of vitamin B-12 and folic acid in the diet may increase the risk of a person developing anaemia, thus increasing the risk of orthostatic hypotension
- Pregnancy - hypotension during pregnancy due to the demand for extra demands of nourishing the baby as well as well as drastic hormonal changes.
These blood pressure changes are most common in the first and second trimesters of the pregnancy and are typically not dangerous, with most pregnant women being asymptomatic or only experiencing mild symptoms.
Even so, regular medical and blood pressure tests are still very important, as infections, anaemia and prolonged bed rest and more may all increase the severity of hypotension
- Sepsis (Severe Infection) - sepsis, or septic shock occurs when the bacteria responsible for an infection leaves the site of the initial infection (such as a lung or stomach infection) and enters the bloodstream. Toxins produced by the bacteria are carried by the bloodstream causing blood vessels not only near the initial source of infection but around the body to be affected.
Sepsis may lead to a drastic and potentially deadly drop in blood pressure.
Complications of Hypotension
A moderate drop in blood pressure may cause bouts of dizziness, fainting, weakness and loss of equilibrium leading to injury due to falling.
Severe hypotension may be extremely dangerous as the lack of pressure leaves the body unable to properly deliver oxygen around the body, leading to organ failure, damage and even death.
Schedule an appointment to see a doctor and have your blood pressure checked. The fastest and easiest way to search for and book healthcare appointments online is through MyHealth1st.
Treatment for Low Blood Pressure
Asymptomatic hypotension or cases that only display mild symptoms rarely require treatment but may benefit from some lifestyle changes.
If you have low blood pressure and experience symptoms, treatment varies due to the severity and underlying cause. If no identifiable cause is present, treatment typically consists of discovering ways to increase your blood pressure rather than treating the underlying cause.
Possible treatment options for hypotension include:
- Medications
If the hypotension is caused by a drug that has been prescribed for hypertension or is causing hypotension due to an allergic reaction to the medication or because of a negative reaction in combination with other drugs, treatment will focus on either finding replacement drugs, or lowering dosages until a desirable outcome is achieved. If the cause of low blood pressure isn’t identifiable, drugs, such as fludrocortisone (used to boost blood volume), or midodrine (used to increase standing blood pressure in the treatment or orthostatic hypotension) may be prescribed. If the underlying cause of hypotension is known, medications may be prescribed as part of the treatment of the underlying disorder. - Lifestyle Changes
Treatment for hypotension may also include a number of lifestyle changes, such as:
- Compression - wearing compression leggings may help blood to stop pooling in your legs lessening the symptoms or instances of orthostatic hypotension. Some people may react better to abdominal binding that compression leggings
- Diet - eating smaller, low carb meals may help alleviate symptoms of postprandial hypotension. Drinking a cup or two of strong coffee (or other caffeinated beverage) with breakfast may also help reduce symptoms. An increase in salt intake may help raise blood pressure but too much sodium in the diet may cause hypertension.
- Drink More Water - keeping up your fluid intake both increased the volume of blood (this is why you’re told to drink a couple of glasses of water before you do in for a blood test) and protects against dehydration, helping stave off two potential causes of hypotension
- Exercise - between 30 and 60 minutes of physical exercise a day, alternating between cardio exercise and resistance exercise may help raise your heart rate and blood pressure.
If you find yourself getting dizzy when you stand up from a seated or prone position, or experience lightheadedness a few hours after eating, you may be experiencing the symptoms of hypotension.