Low Blood Pressure
What is low blood pressure?
Blood pressure is the measure of the pressure of blood inside arteries when your heart pumps (systolic pressure) and when it is at rest (diastolic pressure). While there are thresholds for defining high blood pressure (hypertension), there is no specific definition of low blood pressure (hypotension). Instead, doctors consider blood pressure to be too low if it causes symptoms. It’s possible for people with a normal blood pressure (which is defined as less than 120/80 mmHg) to experience symptoms if their blood pressure goes lower than 90/60 mmHg. However, low blood pressure can be normal in healthy people with small stature and athletes, and treatment may not be necessary.
There are three main types of clinically significant low blood pressure: orthostatic hypotension, neurally mediated hypotension, and hypotension linked to shock.
Low blood pressure due to shock is a serious, life-threatening situation. Seek immediate medical care (call 911) for serious symptoms, such as decreased level of consciousness or fainting, chest pain, rapid heart rate, irregular heart rhythm, shortness of breath or lack of breathing, sudden swelling of the face or tongue, dizziness or lightheadedness that does not resolve with sitting or lying down, high fever (higher than 101°F), decreased or absent urine output, or profuse sweating.
If your low blood pressure symptoms are persistent or cause you concern, seek prompt medical care. Prompt medical care is also warranted for prolonged vomiting or diarrhea, increased urinary frequency or urgency, burning with urination, coughing up sputum, or the inability to eat or drink.
What are the different types of low blood pressure?
The three main types of clinically significant low blood pressure are:
Orthostatic hypotension occurs when your blood pressure drops when you sit up or stand up after lying down. It causes symptoms including dizziness or feeling faint. Normally, your circulatory system is able to adjust to changes in position. It usually restores blood pressure quickly, although sometimes you may need to sit or lie down while recovering. Postprandial hypotension is a type of orthostatic hypotension that occurs after meals.
Neurally mediated hypotension
In neurally mediated hypotension, your blood pressure decreases after extended periods of standing. It may cause dizziness, faintness, and nausea. This type of low blood pressure is the result of abnormal signaling of the brain and nerves. It is most common in children and young adults and typically resolves over time.
Hypotension linked to shock
Low blood pressure linked to shock is a serious condition that interferes with blood flow to your vital organs. The drop in blood pressure is more severe than in orthostatic hypotension or neurally mediated hypotension. And it doesn’t improve when you lay (or fall) down. Shock can be due to significant blood loss, severe allergic reactions, serious infections, large burns, and poisoning.
What other symptoms might occur with low blood pressure?
Low blood pressure symptoms can vary depending on the underlying disease, disorder or condition. Symptoms that frequently affect the cardiovascular system may also involve other body systems.
Cardiovascular system symptoms that may occur along with low blood pressure
Low blood pressure may accompany other symptoms affecting the cardiovascular system including:
- Chest pain or pressure
- Irregular heart rhythms (arrhythmias)
- Rapid heart rate (tachycardia)
Other symptoms that may occur along with low blood pressure
Low blood pressure may accompany symptoms related to other body systems including:
- Cold, clammy skin
- Decreased urine output
- Dizziness or lightheadedness
- Dry mucous membranes (for example, in your mouth or nose)
- Feeling faint or fainting
- Lost elasticity of the skin (it stays pinched for several seconds after you pinch it)
- Swelling in the face or tongue
Serious symptoms that might indicate a life-threatening condition
In some cases, low blood pressure may be a symptom of a life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:
- Bluish coloration of the lips or fingernails
- Change in level of consciousness or alertness, such as passing out or unresponsiveness
- High fever (higher than 101°F)
- Not producing any urine
- Rapid heart rate (tachycardia) or irregular heart rhythm (arrhythmia)
- Respiratory or breathing problems, such as shortness of breath, difficulty breathing, labored breathing, wheezing, not breathing
- Severe pain
- Sudden swelling of the face, lips or tongue
- Uncontrolled or heavy bleeding, hemorrhage
What causes low blood pressure?
Causes of low blood pressure include sudden changes of position (orthostatic hypotension), blood volume redistribution in response to eating (postprandial hypotension), abnormal brain signaling (neurally mediated hypotension), and conditions that cause shock. Medications, heart disease, pregnancy, bedrest, malnutrition, and other health conditions can also contribute to low blood pressure.
Cardiovascular causes of low blood pressure
Low blood pressure may be caused by cardiovascular conditions including:
- Bradycardia (slow heart rate)
- Heart attack
- Heart failure (deterioration of the heart’s ability to pump blood)
- Hypotension (orthostatic, neural or shock)
Other causes of low blood pressure
Low blood pressure can also be caused by other diseases, disorders or conditions including:
- Alcohol use
- Certain medications, including ACE inhibitors, angiotensin receptor blockers, beta blockers, calcium channel blockers, diuretics, erectile dysfunction drugs, narcotics, nitrates, some antianxiety medications and antidepressants, and some anti-Parkinson’s drugs
- Endocrine diseases, such as Addison’s disease (deceased production of hormones by the adrenal glands), diabetes (chronic disease that affects your body’s ability to use sugar for energy), hypothyroidism (underactive thyroid), or parathyroid disease
- Extended bedrest
- Hypovolemia (decreased blood volume)
Serious or life-threatening causes of low blood pressure
In some cases, low blood pressure may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These include:
- Arrhythmia (irregular heart rhythm)
- Extensive burns
- Heart attack
- Hemorrhage or internal bleeding
- Hypovolemic shock
- Pulmonary embolism
- Septic shock (shock due to sepsis, a life-threatening reaction to an infection)
When should you see a doctor for low blood pressure?
Low blood pressure is not always a reason for concern. It can be normal for certain people. If you do not have symptoms, it may only require monitoring during your annual checkup.
If you get dizzy or lightheaded once in a while, keep track of the circumstances. People with low blood pressure may find they get dizzy after a hot bath, being in the sun a long time, or other situations. Mention this to your doctor and take precautions to avoid falls and other problems. Try drinking more water or have a sports drink or electrolyte replacement drink. Including salt in your diet can help as well. Your doctor can help you find the right balance for you.
Call 911 or go to your nearest emergency room for potentially serious hypotension symptoms including:
- Confusion, fainting, or loss of consciousness
- Falls that result in potential injuries
- Heart attack or stroke symptoms
- Irregular heartbeat or weak pulse
- Pale, cold or clammy skin
- Problems breathing, shortness of breath, or breathing that is rapid or shallow
- Swelling of the face, lips, tongue or throat
- Uncontrollable bleeding
How is the cause of low blood pressure diagnosed?
To diagnose your condition, your doctor or licensed healthcare practitioner will ask you several questions related to your low blood pressure including:
- When did you first notice your low blood pressure?
- What seems to bring it on?
- Does anything make it improve?
- Do you have any other symptoms?
- Do you have any other medical problems?
- What medications are you taking?
- Do you drink alcohol or use any illicit drugs?
Your doctor will also perform a physical exam and check your blood pressure. If the results are in the low blood pressure range, your doctor may recommend testing including:
- Blood and urine tests to check for problems like anemia, diabetes, hormone problems, or nutritional deficiencies
- ECG (electrocardiogram) to check for electrical abnormalities in the heart
- Title table test to check how your body responds to changes in position
- X-ray of the chest to check the size and shape of your heart
It is not always possible to diagnose an underlying cause or condition. If the problem persists and your provider is unable to determine a cause, seeking a second opinion may give you more information and answers.
How do you treat low blood pressure?
When people are otherwise healthy and low blood pressure doesn’t cause symptoms, no treatment is necessary. Even if symptoms occur occasionally or are mild, doctors may not recommend treatment. This is because low blood pressure is generally a healthy thing for your heart. (Normal blood pressure is less than 120/80 mmHg.)
When people have concerning symptoms, treatment will depend on the cause. If medications are causing the problem, your doctor may adjust the dose or switch to another drug. For other underlying causes, treating them may help resolve your symptoms.
Treatments to raise your low blood pressure
Sometimes, there is no clearly identifiable cause of low blood pressure. Or there may not be an effective treatment for the underlying cause. In these cases, the goal is to help prevent symptoms of low blood pressure. Your doctor may recommend the following strategies:
- Drink more water: Water keeps your blood volume high and prevents dehydration. Sports drinks and rehydration drinks also add electrolytes.
- Eat some salt: Salt can help raise your blood pressure. Many people need to limit salt because it makes their blood pressure too high. For people with low blood pressure, salt can actually be helpful. However, too much salt can be bad for your heart and kidneys. Check with your doctor to find the right amount of salt intake for you.
- Wear compression stockings: These stockings stop blood from pooling in your lower legs and promote better circulation.
If you have orthostatic hypotension, your doctor may prescribe a medication, such as midodrine (Orvaten).
Home remedies for raising low blood pressure
Lifestyle changes may help some people with low blood pressure including:
- Avoiding standing for long periods of time or spending long periods in hot, humid conditions
- Changing positions slowly and deliberately
- Drinking caffeine in the morning, if it is safe for you, but avoid it for the rest of the day
- Eating several small meals throughout the day, which can help even out blood pressure and blood sugar
- Exercising on a regular basis, including both strength and cardio activities
- Limiting alcohol, which is a vasodilator—it relaxes blood vessels—and can contribute to dehydration
Alternative treatments for low blood pressure
Certain herbal supplements can increase blood pressure including:
- Bitter orange
- Ephedra or ma-huang
- Natural licorice (not licorice flavoring)
- St. John’s wort
Be sure to check with your doctor before starting any herbal supplement. Make sure all your healthcare providers, including your pharmacist, are aware of the supplement you are taking.
What are the potential complications of low blood pressure?
Because low blood pressure can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:
- Brain damage
- Irreversible vision loss
- Heart disease
- Injury due to fainting
- Kidney damage
- Loss of strength
- Multiple organ failure
- Permanent disability