Low Blood Pressure (Hypotension): Causes, Symptoms And Treatments (2024)

Blood pressure is the force of blood as it pushes against the walls of the arteries as the heart pumps blood.

For most adults, normal blood pressure is marked by a systolic reading of less than 130 mmHg and a diastolic reading of less than 80 mmHg. Systolic blood pressure (the top number in a blood pressure reading) indicates the force of blood against artery walls during a heartbeat, and diastolic blood pressure (the bottom number in a blood pressure reading) is a measure of the pressure blood exerts on artery walls while the heart rests between beats.

When blood pressure drops below a systolic reading of 90 mmHg and a diastolic reading of 60 mmHg, it can be considered low blood pressure. However, not all blood pressure readings below these levels are automatically a cause for concern.

Furthermore, some people who are accustomed to elevated blood pressure may experience symptoms of hypotension when their blood pressure drops to “normal” levels.

What Is Considered Dangerously Low Blood Pressure?

“If blood pressure levels become too low, vital organs may not be receiving blood quickly enough, and the important nutrients [blood carries]—including oxygen—may not be getting to where they need to be in a timely fashion,” says Collin Johnston, M.D., a board-certified physician specializing in vascular procedures at Vein Envy in Arizona. This deprivation can lead to shock, coma and even death.

However, the exact level at which such health risks occur can vary from person to person. For example, people who are very physically active and in great shape may naturally have lower blood pressure due to the efficiency of their cardiovascular system, says Dr. Johnston.

“Blood pressure is a product of blood flow circulating in the vessels and the resistance of vessels (which include veins and arteries),” explains Giv Heidari, M.D., a cardiologist and director of the Hypertension Clinic at Loma Linda University International Heart Institute. “Blood pressure drops when either the vascular resistance or blood flow drops,” he adds.

There are several factors that could contribute to lower-than-normal blood pressure readings, including:

• Dehydration
• Infection or sepsis
• Blood loss
• Certain medications, including diuretics and all medications used to treat high blood pressure (hypertension)
• Cardiac conditions, such as an irregular heartbeat, valve issue, fluid around the heart, heart attack or heart failure
• Anaphylaxis, a severe allergic reaction that can result in breathing problems, a swollen throat and itching
• Pregnancy
• Weight loss that renders a person’s current medication dose(s) too high for their new body weight

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Low blood pressure (hypotension) - Diagnosis and treatment

There are several classifications of low blood pressure, including:

• Orthostatic hypotension, commonly known as postural hypotension, which occurs when blood pressure drops as a person moves from a seated or lying position to a standing position.
• Postprandial hypotension, which is defined as a drop in blood pressure after eating a meal.
• Neurally mediated hypotension, also referred to as vasovagal syncope, which is characterized by a drop in blood pressure resulting from standing for too long or exposure to a noxious stimulus.
• Multiple system atrophy with orthostatic hypotension, formerly known as Shy-Drager syndrome, which is a brain disorder that affects how the autonomic nervous system (which controls involuntary body functions like blood pressure regulation) functions. It’s associated with very high blood pressure when lying down, followed by a drop in blood pressure upon standing. It’s common in patients with Parkinson’s disease.

“Low blood pressure is considered a medical condition when there are symptoms related to it,” explains Dr. Heidari. However, many people do not experience noticeable symptoms.

Common symptoms associated with low blood pressure include:

• Blurred vision
• Confusion
• Lightheadedness or fainting
• Fatigue
• Headache
• Nausea
• Heart rate irregularities, such as palpitations or rapid heart rate

“Not every person with lower-than-usual [blood pressure] numbers needs treatment,” says Dr. Heidari. “Treatment is needed if there are symptoms related to low blood pressure or if the low blood pressure is the result of medication overdose, a systemic infection, trauma or body organ failure,” he adds.

“In fact, if the patient is not displaying or complaining of any significant symptoms, such as blurred vision, dizziness with position changes (laying to sitting or sitting to standing), fainting, excessive fatigue or difficulty concentrating, the physician may recommend monitoring blood pressure levels with regular checkups,” says Dr. Johnston.

Treatment for low blood pressure generally involves addressing the underlying medical condition or medication that’s causing the decrease in pressure, notes Dr. Johnston.

Common treatments for low blood pressure include:

• Increasing intake of fluids and electrolytes
• Taking medications to raise blood pressure.
• Treating underlying conditions, such as anemia or thyroid issues
• Standing from a seated or lying position more slowly
• Wearing compression socks or stockings

If you have one abnormal blood pressure reading, it may not be a cause for concern. However, it’s important to schedule an appointment with your health care provider if you notice any of the symptoms associated with low blood pressure.

In some cases, immediate medical attention may be needed. Dr. Heidari recommends seeing a medical provider immediately if you experience low blood pressure in the following instances:

• In the setting of a systemic infection
• When there’s evidence of organ damage or failure, such as heart attack
• Internal bleeding following an injury or fall
• Temporarily losing consciousness or passing out
• If you have known medical condition, such as kidney, heart or liver failure
• If you have always had normal blood pressure and suddenly blood pressure drops without an obvious cause
• If the cause of dehydration is ongoing, such as frequent diarrhea or vomiting
• Experiencing signs of shock, including rapid breathing, abnormal pulse or a bluish skin tone

Fortunately, with the right lifestyle modifications and treatment, doctors can successfully manage low blood pressure in most patients, says Dr. Heidari. In any case, it’s important to follow your doctor’s recommendations to keep your blood pressure within a healthy range.