High blood pressure (hypertension) can put you at risk of stroke, heart attack, kidney disease, eye damage, and even dementia.
And if your blood pressure falls too low (called hypotension), it can cause mild problems (such as fainting) or potentially damage the heart and brain.
You want your blood pressure to be somewhere in the middle for optimal health, so it’s important to keep tabs on yours with regular blood pressure readings at the doctor’s office.
Since low blood pressure tends to be overshadowed by hypertension, this article will break down everything you need to know about hypotension, including the symptoms, causes, diagnosis, types, treatment, and when to see a doctor.
What Is Hypotension (Low Blood Pressure)?
Hypotension occurs when the blood pumped through the arteries flows at a lower than average rate—a blood pressure reading lower than 90/60 mm Hg, to be exact. (To put that into perspective, normal blood pressure is considered to be between 90/60 mm Hg and 120/80 mm Hg.)
Some people have low blood pressure all the time due to genetic factors; for these individuals, it’s usually not a concern.
Other people experience a sudden drop in blood pressure or have low blood pressure that may be linked to a health problem.
Symptoms of Low Blood Pressure
Hypotension is often asymptomatic, which is why it’s common for it to go unnoticed. When present, symptoms of low blood pressure may include:
- Blurry vision
- Nausea or vomiting
- Cold, clammy, pale skin
- Rapid, shallow breathing
- Lack of concentration
- Unusual thirst
Causes of Low Blood Pressure
A variety of factors, from certain medications to medical conditions, can cause short- and long-term drops in blood pressure.
Medicines and substances that can cause low blood pressure include:
- Tricyclic antidepressants
- Medication for high blood pressure, such as beta blockers and alpha blockers
- Erectile dysfunction medication
Conditions that can cause low blood pressure include:
- Heart problems
Conditions that can cause a sudden drop in blood pressure include:
- Loss of blood from bleeding
- Low body temperature
- Sepsis (a severe blood infection)
- Severe dehydration from vomiting, diarrhea, or fever
- A reaction to medication or alcohol
- Anaphylaxis (a severe allergic reaction)
Diagnosing Low Blood Pressure
If blood pressure readings indicate low blood pressure that is abnormal for you, your doctor or provider will work with you to determine the underlying cause.
They may do a physical exam and ask about your:
- Medical history, including your normal blood pressure
- Symptoms and what causes those symptoms
- Current medications
- Recent illnesses, accidents, or injuries (if any)
Additionally, they may do some tests, including:
- Electrocardiogram (ECG) to check your heart
- Blood work to check your blood sugar levels, red blood cell levels, thyroid, and for any vitamin deficiencies
- X-rays to examine the abdomen or chest
Types of Low Blood Pressure
Low blood pressure is divided into several different types, which are differentiated by their causes.
Orthostatic hypotension (or postural hypotension) is when blood pressure drops due to a change in position—most commonly, when someone goes from lying down to standing up.
Blood pressure normally decreases slightly when this happens, because gravity causes blood in the upper body to move to the lower body when you stand.
In most people, the body re-regulates blood pressure quickly afterward. But in people with orthostatic hypotension, blood pressure remains low for longer and causes problematic symptoms.
Severe and persistent orthostatic hypotension increases the risk of heart attack, heart failure, stroke, chronic kidney failure, and injuries from fainting spells.
Postprandial hypotension is when blood pressure drops 1-2 hours after eating a meal. This type of low blood pressure is most common in older adults, especially those with high blood pressure or autonomic nervous system disorders like Parkinson’s disease.
After a meal, blood flow to the intestine increases to facilitate digestion.
To keep blood pressure steady when this happens, the heart beats faster and blood vessels constrict. But this effect is dampened in people with postprandial hypotension, leading to a decrease in blood pressure.
People who have postprandial hypotension may experience dizziness, light-headedness, faintness, and falls.
Neurally mediated hypotension (also known as vasovagal syncope or the fainting reflex) is when blood pressure drops after standing for a long time, or in response to stress or fear.
NMH is most common in young adults and children.
Standing for long periods causes blood to pool in the lower limbs and reduces blood flow to the heart and brain (and other organs). Heart rate also slows in people with neurally mediated hypotension.
Combined with lower blood pressure, this can decrease blood flow to the brain and may lead to fainting.
A “vagal response” to fear, stress, or pain, can also cause fainting in a similar way.
Intense or unpleasant emotions can stimulate your vagus nerve, which then reduces blood flow to the heart and brain temporarily, which can cause nausea, sweating, looking pale, seeing stars, and fainting.
You can prevent these types of fainting by making sure to eat and drink regularly, slightly moving and bending your knees when standing for long periods, and sitting or lying down if you start to notice yourself feeling faint or dizzy.
Another type of hypotension, known as Shy-Drager syndrome, occurs when there is damage to the autonomic nervous system.
This part of the nervous system controls blood pressure and heart beat, among other things. Shy-Drager syndrome can cause symptoms similar to Parkinson’s disease, including tremors, balance difficulties, rigid muscles, and impaired movement.
Treating Low Blood Pressure
Lower than normal blood pressure in a healthy person that does not cause any symptoms often does not require treatment.
In other cases, treatment depends on the symptoms and the underlying cause of low blood pressure. Both lifestyle changes and medication can help manage low blood pressure.
Several lifestyle changes may improve low blood pressure, including:
- Drinking more water to prevent dehydration
- Slightly increasing sodium intake, which increases blood pressure
- Avoiding or reducing alcohol consumption
- Getting up slowly after sitting or lying down
- Avoiding standing for a long time (if you have NMH)
- Using compression stockings to decrease blood pooling in the legs
Depending on the cause of your hypotension, your doctor may prescribe medication. The most common medications used to treat the condition include:
- Fludrocortisone (Florinef): to increase blood volume (more volume decreases blood pressure)
- Midodrine (ProAmatine and Orvaten): to increase blood pressure
Risks of Low Blood Pressure
The main risks of low blood pressure are falling and fainting, which can lead to injuries.
If left untreated, acute severe hypotension can limit how much oxygen the organs receive.
Called shock, this can cause damage to the heart and brain and can be life-threatening if not treated.
When to See a Doctor
See a healthcare provider if you experience symptoms of low blood pressure such as frequent, unexplained fainting or dizziness. Also contact a doctor if you have:
- Black or maroon stools
- Chest pain
- Fever higher than 101°F (38.3°C)
- Irregular heartbeat
- Shortness of breath
How K Health Can Help
Did you know you can get affordable primary care including hypotension testing, diagnosis, and treatment with the K Health app?
Download K Health to check your symptoms, explore conditions and treatments, and if needed text with a provider in minutes. K Health’s AI-powered app is based on 20 years of clinical data.
Frequently Asked Questions
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
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Low Blood Pressure (Hypotension). (2019).
Orthostatic Hypotension. (2020).