Hypotension vs. Hypertension | Why Low Blood Pressure is Also Important to Monitor

What is Hypotension?

Hypotension, not to be confused with Hypertension, describes low blood pressure which can result in the brain not receiving enough blood. While low blood pressure is often perceived as a positive alternative to the more widely known high blood pressure, there are dangers associated with a BP lower than 90/60 mmHg. In severe cases, low blood pressure can be life-threatening.

What is Blood Pressure (BP)?

Blood pressure is the force of blood pushing against the walls of your arteries as the heart pumps blood. It is usually described in correlation of: systolic and diastolic. Blood pressure is measured both when your heart beats, and during the periods of rest between heartbeats. The measurement of your blood pumping through your arteries when the ventricles of the heart squeeze is called systolic pressure or systole. The measurement for the periods of rest is called diastolic pressure, or diastole. A blood pressure of 90/60 mmHg means that the systolic pressure is 90 millimetres of mercury (mmHg), a manometric unit of measurement for pressure, and that the diastolic pressure is 60 millimetres of mercury.

What causes Hypotension?

Some people naturally have low blood pressure, it is normal for them and is no cause for concern. However, people who experience a sudden drop in blood pressure, or have low blood pressure that may be linked to a health problem, are typically recommended to monitor their BP on a regular basis. Certain conditions affect blood pressure and can cause Hypotension. According to the American Heart Association (AHA) low blood pressure can occur due to:

  • Prolonged bed rest

  • Pregnancy
    • During the first 24 weeks of pregnancy, it’s common for blood pressure to drop.

  • Decreases in blood volume
    • A significant loss of blood from major trauma, dehydration or severe internal bleeding reduces blood volume, leading to a severe drop in blood pressure.

  • Certain medications
    • A number of drugs can cause low blood pressure, including diuretics and other drugs that treat hypertension.

  • Heart problems
    • Heart conditions such as abnormally low heart rate (bradycardia), problems with heart valves, heart attack and heart failure can cause hypotension since your heart may not be able to circulate enough blood to meet your body’s needs.

  • Endocrine problems
    • Complications with hormone-producing glands in the body’s endocrine systems; specifically, an underactive thyroid (hypothyroidism), parathyroid disease, adrenal insufficiency (Addison’s disease), low blood sugar and, in some cases, diabetes, can cause low blood pressure.

  • Severe infection (septic shock)
    • Septic shock can occur when bacteria leave the original site of an infection and enter the bloodstream. The bacteria then produce toxins that affect blood vessels, leading to a profound and life-threatening decline in blood pressure.

  • Allergic reaction (anaphylaxis)
    • Anaphylactic shock is a sometimes-fatal allergic reaction that is characterized by breathing problems, hives, itching, a swollen throat and a sudden, dramatic fall in blood pressure.

  • Neurally mediated Hypotension
    • This disorder causes blood pressure to drop after standing for long periods, and occurs because of a miscommunication between the heart and the brain.

  • Nutritional deficiencies
    • A lack of the essential vitamins B-12 and folic acid can cause anemia, which in turn can lead to low blood pressure

Diagnosis

When diagnosing a patient, healthcare providers must first determine what type of Hypotension the patient has and what the underlying cause is. This is made more difficult due to the sheer number of potential sources. Reviewing a patient’s medical history, doing a physical exam and measuring their blood pressure, are all common steps in the diagnosis process. Beyond these common procedures it may also be necessary to do blood tests, electrocardiograms (ECGs), echocardiograms, and/or the tilt table test among other diagnostic tests.


  • Blood tests:
    • Blood tests are done to check your blood sugar levels and blood cell count. Having these measurements helps your doctor determine if your low blood pressure is caused by low blood sugar (hypoglycemia) or anemia.

  • Electrocardiograms:
    • An Electrocardiogram (ECG) is a noninvasive test which records the heart's electrical activity and is able to detect heart structural abnormalities, irregularities in heart rhythm, heartbeat speed, and blood supply problems.

  • Echocardiograms:
    • An echocardiogram uses high-frequency sound waves to noninvasively obtain images of your heart and its chambers. The images show how your heart looks, its size and how well it is pumping blood.

  • Tilt table test:
    • A tilt table test, occasionally called upright tilt testing, attempts to determine the cause of syncope by rapidly creating changes in posture from lying to standing. This is achieved by having patients lie flat on a bed or table that quickly moves from lying position to an upright position while connected to electrocardiogram (ECG) and blood pressure monitors.

Types of Hypotension

Hypotension has several distinct classifications which are divided according to when your blood pressure drops.

Orthostatic

Orthostatic Hypotension occurs when you transition from sitting or lying down to standing. It is common in people of all ages. As the body adjusts to the position change there may be a brief period of dizziness due to a drop in blood pressure. A drop in systolic BP of ≥ 20 mmHg, or in diastolic BP of ≥ 10 mmHg, or experiencing lightheadedness or dizziness is considered abnormal by the CDC.

Postprandial

Postprandial Hypotension is an excessive drop in blood pressure that occurs right after eating a meal. It is a type of orthostatic Hypotension that is thought to be related to the pooling of blood in the abdominal organs during the process of digestion. As a result of this pooling, the amount of blood available to the general circulation decreases, causing a drop in blood pressure. Dizziness, light-headedness, and falls may occur due to the resulting low blood pressure. Older adults are more likely to develop postprandial Hypotension, but eating small, low-carbohydrate meals frequently may help.

Neurally Mediated

Neurally mediated Hypotension, also referred to as vasovagal syncope or the fainting reflex, happens after you stand for a long time. Blood pools in the legs and ankles which causes a lack of blood flow to the heart, brain and other organs. Children are more likely to experience this form of Hypotension than adults. Emotionally upsetting events can also cause this drop in blood pressure.

Severe

Severe Hypotension is closely related to shock, which is a critical condition brought on by the sudden drop in blood flow throughout the body. When a person is in shock, his or her organs aren't getting enough blood or oxygen. Severe Hypotension can be life-threatening if not treated promptly.

What are the Symptoms of Hypotension?

People with Hypotension may experience symptoms when their blood pressure drops below 90/60 mmHg. Symptoms of low blood pressure can include:


  • Fatigue

  • Lightheadedness

  • Dizziness

  • Nausea

  • Clammy skin

  • Depression

  • Loss of consciousness

  • Blurry vision


Symptoms can range in severity. For some people Hypotension expresses itself mildly and may seem only slightly uncomfortable, while others may feel consistently and severely ill. Extreme Hypotension can result in this life-threatening condition. Signs and symptoms of hypovolemic (Hypotensive) shock include:


  • Confusion, especially in older people

  • Cold, clammy, pale skin

  • Rapid, shallow breathing

  • Weak and rapid pulse


If you experience any dizziness, lightheadedness, nausea or other symptoms, you should consider consulting your healthcare provider. Keeping a record of your symptoms, activities, and the time they occurred may help with your diagnosis.

Treatment for Hypotension:

Low blood pressure that is asymptomatic, or causes only mild symptoms, rarely requires treatment and can be safely managed with very little to no changes necessary.

For symptomatic Hypotension, due to the wide range of potential causes and types of low blood pressure, there are unique solutions depending on the underlying cause. Treatment could include medication or dietary changes, lifestyle adjustments, and more.

If it's not clear what's causing low blood pressure or no treatment exists, patients and providers will focus on raising blood pressure and reducing the signs and symptoms of Hypotension. Depending on patient age, health status, and the type of low blood pressure, there are several recommended actions that can safely increase blood pressure according to the Mayo Clinic:

  • Increase salt intake.
    • Experts usually recommend limiting salt in your diet because sodium can raise blood pressure, sometimes dramatically. For people with low blood pressure, that can be a good thing.

    • Excess sodium can lead to heart failure, especially in older adults, so it's important to check with your doctor before increasing the salt in your diet.

  • Drink more water.
    • Fluids increase blood volume and help prevent dehydration, both of which are important in treating Hypotension.

  • Wear compression stockings.
    • The elastic stockings commonly used to relieve the pain and swelling of varicose veins can help reduce the pooling of blood in your legs.

    • Some people tolerate elastic abdominal binders better than they do compression stockings.

  • Medications.
    • Several medications can be used to treat low blood pressure that occurs when you stand up (orthostatic Hypotension). For example, the drug fludrocortisone, which boosts your blood volume, is often used to treat this form of low blood pressure.

  • Drink less alcohol.
    • Alcohol is dehydrating and can lower blood pressure, even if you drink in moderation.

  • Pay attention to your body positions.
    • Gently move from a prone or squatting position to a standing position. Don't sit with your legs crossed.

    • If you begin to get symptoms while standing, cross your thighs in a scissors fashion and squeeze, or put one foot on a ledge or chair and lean as far forward as possible. These moves encourage blood flow from your legs to your heart.

  • Eat small, low-carb meals.
    • To help prevent blood pressure from dropping sharply after meals, eat small portions several times a day and limit high-carbohydrate foods such as potatoes, rice, pasta and bread.

    • Your doctor also might recommend drinking one or two strong cups of caffeinated coffee or tea with breakfast. ingDon't drink caffeinated products throughout the day because you will become less sensitive to the effects of caffeine.

  • Exercise regularly.
    • Aim for 30 to 60 minutes a day of exercise that raises your heart rate and resistance exercises two or three days a week. Avoid exercising in hot, humid conditions.


Disclaimer: All of the material provided above is for informational purposes only. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. Casana does not endorse any of the products or services mentioned in this post.

Citations:

American Heart Association. Low blood pressure - when blood pressure is too low. www.heart.org. (n.d.).

https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/low-blood-pressure-when-blood-pressure-is-too-low.

Mayo Foundation for Medical Education and Research. (2020, September 22). Low blood

pressure (Hypotension) - Diagnosis & treatment. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/low-blood-pressure/diagnosis-treatment/drc-20355470.

Mayo Foundation for Medical Education and Research. (2020, September 22). Low blood

pressure (Hypotension) - Symptoms & causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/low-blood-pressure/symptoms-causes/syc-20355465.

Roth, E. (2019, May 8). Everything you need to know about low blood pressure. Healthline.

https://www.healthline.com/health/Hypotension#treatment.

U.S. Department of Health and Human Services. (n.d.). Low blood pressure. National Heart

Lung and Blood Institute. https://www.nhlbi.nih.gov/heal...;


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