What Is Low Blood Pressure (Hypotension)?

Medically reviewed by Jeffrey S. Lander, MD

Low blood pressure—also known as hypotension—is a serious condition that can affect the blood flow and oxygen to your organs. While normal blood pressure is 120/80 mmHg, low blood pressure is usually defined as less than 90/60 mmHg.

While low blood pressure doesn’t always cause symptoms, some people may experience dizziness, nausea, or fainting. These symptoms can interrupt your ability to function throughout the day and can be very concerning as they might lead to falls or other injuries.

Many different conditions can cause low blood pressure, such as taking certain medications or having an underlying condition or infection. The good news is that treatments can help bring your blood pressure to a normal range. Most treatments, however, will focus on treating the underlying condition that is causing hypotension.

If you think you have low blood pressure or begin to experience symptoms, it’s good practice to visit your healthcare provider for proper testing. Getting an early diagnosis can help you get started on treatment sooner and improve your quality of life.

Related: Signs and Symptoms of Low Blood Pressure

Symptoms

Sometimes, you might have low blood pressure without experiencing any symptoms at all. However, if you do experience low blood pressure symptoms, they may include:

• Blurry vision

• Dizziness

• Fainting

• Headache

• Nausea

• Rapid heart rate

• Weakness

• Feeling thirsty

• Trouble concentrating

• Depressive moods

• Fatigue

Sometimes, low blood pressure can cause severe symptoms. Symptoms that should warrant immediate medical care include:

• Blue-colored lips or nail beds

• Cold and clammy skin

• Difficulty breathing

• Weak pulse or heart palpitations

These symptoms can be due to severely low blood pressure or if you’re in shock. In such cases, you or a loved one should call 911 and seek medical attention as soon as possible.

Causes

The potential causes of low blood pressure can either be due to acute (rapidly occurring) or chronic (long-term) medical conditions, not having enough blood or water in your body, or taking medications.

If your healthcare provider notices your blood pressure reading is a bit too low, they may screen you for the following conditions and situations that may be causing hypotension:

• Overusing blood pressure medication

• Taking certain antidepressants

• Dehydration, especially after having an illness (e.g., stomach flu)

• Pregnancy, which can cause hypotension during the first 24 weeks

• Septic shock or severe infection

• Severe allergic reactions such as anaphylaxis

• Significant blood loss

• Anemia or being iron-deficient

• Heart failure

• Diabetes

• Thyroid disease

• Orthostatic hypotension, which is low blood pressure that affects older adults and young women

Diagnosis

Healthcare providers diagnose hypotension by measuring your blood pressure through a blood pressure machine. They may do this by applying a blood pressure cuff on your arm or using an arterial line (a small tube) that they insert into your artery through your wrist.

While blood pressure monitors and cuffs are the primary ways to measure your blood pressure, a provider may use an arterial line for people with severely low blood pressure whose measurements can’t be picked up from an inflatable cuff.

When you get a blood pressure reading, your provider is looking for two numbers:

• Systolic blood pressure: The first number that checks the pressure inside your arteries (blood vessels) when your heart is beating

• Diastolic blood pressure: The second number that measures the pressure inside your arteries when your heart is resting in between beats

Generally, normal blood pressure is under 120/80 mmHg (millimeters of mercury). If your blood pressure is less than 90/60 mmHg, this is a sign of low blood pressure. If your healthcare provider is concerned about your blood pressure reading, they will ask about your symptoms, underlying health conditions, or recent lifestyle changes that may need further testing.

Depending on the symptoms you have, your provider can order blood tests or an echocardiogram (ECG) to check for conditions such as anemia, diabetes, or heart disease.

Related: Most People Don't Know What a Normal or Healthy Blood Pressure Is, Study Shows

Treatment

The treatment goals for low blood pressure are to bring your blood pressure into a normal range and treat any underlying conditions that may be causing hypotension in the first place.

Some examples of underlying conditions and your treatment options may include:

Keep in mind: the above table is not an exhaustive list. If your provider finds that your low blood pressure is due to a chronic health condition like diabetes or heart disease, your treatment plan will depend on the treatments available for your particular condition.

Prevention

Because some emergency medical conditions or situations (e.g., trauma or sudden blood loss) can cause low blood pressure, you can’t always prevent hypotension from occurring. However, if your symptoms are due to an underlying condition, you can take some steps to reduce how often you experience low blood pressure episodes. These steps include:

• Slowly standing up after sitting or lying down for an extended time

• Staying hydrated when you’re sick by drinking plenty of fluids

• Checking your blood pressure before taking any medications for high blood pressure

• Wearing compression stockings or socks if you must stand for long periods

• Following your treatment plan for any underlying conditions that you have

If you experience frequent episodes of low blood pressure or have symptoms that are interrupting your daily life, it’s a good idea to check in with your healthcare provider to learn why symptoms are occurring. They can help you find other lifestyle changes to improve your condition or order more testing to figure out the cause of your hypotension.

Living With Low Blood Pressure

Living with hypotension or having a general feeling of being unwell can be frustrating. How your condition progresses will depend on why you’re having low blood pressure in the first place.

Experiencing shock, sepsis (severe infection), or severe blood loss after trauma can all be severe medical emergencies that require immediate care. Your prognosis and treatment plan will depend on how quickly you’re able to recover following any of these traumas.

However, you can correct hypotension if the cause of your low blood pressure is due to other underlying causes. This may include drinking more water, adjusting your medications, or receiving treatment for a different condition—all of which can help your blood pressure return to a normal range.

The important thing to keep in mind is that if you have symptoms or begin to feel unwell, it’s best to err on the side of caution and seek support from your healthcare provider. Even if symptoms seem mild at first, it’s better to get treatment sooner than to risk the possibility of complications.

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