Have you ever stood up too quickly from a chair or from bed and felt a sudden wave of dizziness, seen black spots, or felt like you might faint? This common experience, known as orthostatic hypotension or postural hypotension, is a form of low blood pressure that occurs upon standing. While occasional episodes can happen to anyone, particularly on a hot day or when dehydrated, persistent orthostatic hypotension can be a sign of an underlying medical problem. More importantly, it is a major risk factor for falls and injuries, especially in older adults. Understanding what causes this sudden drop in blood pressure and learning how to manage it are key to maintaining safety, stability and quality of life.

Orthostatic hypotension (also called postural hypotension) is a condition where your blood pressure drops significantly when you stand up from sitting or lying down. To understand why this happens, it is essential to first understand the body’s normal, instantaneous response to standing up.

When you stand, gravity pulls approximately 500 to 800 milliliters of blood downward into your legs and abdomen. This pooling of blood means there is temporarily less blood returning to your heart and, therefore, less blood being pumped up to your brain. Your body has a sophisticated, automatic system to counteract this instantly. This system is part of the autonomic nervous system, which controls all your body’s involuntary functions.

Think of your circulatory system as a tall column of water. When you stand up, it’s like suddenly tilting the column upright, gravity wants to pull all the water to the bottom. A healthy autonomic nervous system acts like an instant, powerful pump and a set of clamps. Specialized pressure sensors in your arteries called baroreceptors detect the drop in pressure and immediately send a signal to the brain. The brain then commands the heart (the pump) to beat faster and tells the blood vessels (the clamps) in your legs and abdomen to constrict. This coordinated response pushes blood back up against gravity, ensuring your brain receives a steady supply of oxygen.

In orthostatic hypotension, this automatic pump-and-clamp system is sluggish, weakened, or broken. The response to standing is too slow or insufficient. As a result, upper body blood pressure plummets, temporarily depriving the brain of adequate blood flow and oxygen, causing classic symptoms of dizziness and lightheadedness.

Medically, a diagnosis is made when, within three minutes of standing, there is a drop in systolic blood pressure (the top number) of at least 20 mmHg or a drop in diastolic blood pressure (the bottom number) of at least 10 mmHg.

Orthostatic hypotension occurs when the body’s normal mechanisms for regulating blood pressure fail upon standing. However, there are many different underlying conditions and factors that can lead to this failure.

The causes can be broadly grouped into several categories:

1. Volume Depletion (Not Enough Fluid in the System): This is one of the most common and easily reversible causes. If there isn’t enough fluid in your blood vessels to begin with, it’s much harder for the body to maintain pressure when you stand up.

• Dehydration: Caused by not drinking enough fluids, especially in hot weather, or from fluid loss due to fever, vomiting, or severe diarrhea.
• Blood Loss: Significant bleeding from an injury or internal source.

2. Medications: Many common medications can cause or worsen orthostatic hypotension as a side effect.

• Blood Pressure Medications: Diuretics (“water pills”), beta-blockers, ACE inhibitors, and calcium channel blockers are all designed to lower blood pressure and can sometimes be too effective.
• Medications for Parkinson’s Disease: Drugs like levodopa can affect blood pressure regulation.
• Certain Antidepressants: Particularly tricyclic antidepressants.
• Alpha Blockers: Used to treat an enlarged prostate (BPH).
• Drugs for Erectile Dysfunction

3. Heart Conditions: Problems with the heart can prevent it from pumping faster or stronger in response to standing.

• Bradycardia: An abnormally slow heart rate.
• Heart Valve Problems: Such as aortic stenosis.
• Heart Failure: A weakened heart muscle cannot pump effectively.

4. Endocrine Disorders Problems with the body’s hormone systems can affect blood pressure.

• Adrenal Insufficiency (Addison’s Disease): A deficiency of the hormone cortisol can cause very low blood pressure.
• Diabetes: Can cause both dehydration (due to high blood sugar) and nerve damage that affects blood pressure control.
• Thyroid Problems

5. Neurological Disorders Some conditions directly damage the autonomic nervous system, impairing its ability to regulate blood pressure.

• Autonomic Neuropathy: Nerve damage from long-term, uncontrolled diabetes is a leading cause. Other causes include alcoholism, certain vitamin deficiencies, and some autoimmune diseases.
• Parkinson’s Disease
• Multiple System Atrophy (MSA) and Pure Autonomic Failure: These are rarer neurodegenerative disorders where orthostatic hypotension is a primary feature.

Orthostatic hypotension occurs when your body is unable to regulate blood pressure quickly enough after a postural change. The primary risk factors include:

• Pregnancy: Hormonal changes and the pressure of the growing uterus on major blood vessels can cause orthostatic hypotension during pregnancy.
• Age: It is much more common in adults over the age of 65 due to a natural stiffening of the arteries, a less responsive autonomic nervous system, and a higher likelihood of having other contributing medical conditions.
• Medications: Taking multiple medications, particularly for high blood pressure or prostate issues, is a major risk factor.
• Certain Chronic Diseases: Having diabetes, Parkinson’s disease, Addison’s disease, or heart failure significantly increases the risk.
• Heat Exposure and Dehydration: Living in a hot climate and not maintaining adequate fluid intake is a common trigger for temporary episodes.
• Prolonged Bed Rest: After being bedridden for a long time, the body can become deconditioned, and the autonomic reflexes can become sluggish.

The hallmark symptom is dizziness or lightheadedness after standing, usually within 1–3 minutes. Symptoms often resolve when sitting or lying down again.

The most common signs and symptoms include:

• Headache or Neck Pain: Some people experience pain across their shoulders and up the back of their neck, sometimes called a “coat hanger headache.”
• Lightheadedness or Dizziness: This is the hallmark symptom.
• Blurred Vision, “Seeing Stars,” or “Tunnel Vision.”
• Weakness: A feeling of the legs being weak or about to give way.
• Fatigue.
• Confusion or difficulty concentrating.
• Syncope (Fainting): This is the most dangerous symptom, as it can lead to falls and serious injuries like fractures or head trauma.
• Nausea.

While an occasional, mild dizzy spell upon standing might be harmless, you should see a healthcare provider if the symptoms are frequent, persistent, or severe. It is especially important to seek medical evaluation if you ever lose consciousness or faint upon standing. A proper diagnosis is needed to identify the underlying cause and prevent potentially dangerous falls.

• Blood Pressure Measurement: The key to diagnosis is measuring the blood pressure and heart rate response to a change in posture. A doctor or nurse will have you lie down for several minutes and will measure your blood pressure. They will then have you stand up and will immediately re-measure your blood pressure and again after one and three minutes of standing. A significant and sustained drop confirms the diagnosis.
• Medical History: A doctor will take a thorough history of your symptoms, your overall health, and, critically, a detailed review of all the medications you are taking, both prescription and over the counter.
• Blood Tests: May be ordered to check for underlying causes like anemia, dehydration, or diabetes.
• Cardiac Tests: An electrocardiogram (ECG) or an echocardiogram may be done to rule out a heart problem as the cause.
• Tilt Table Test: If the cause is not clear, you may be referred for a tilt table test. During this test, you lie on a table that is slowly tilted into an upright position while your blood pressure, heart rate, and symptoms are continuously monitored.
• Clinically, the standing blood pressure test is quick and reliable. If the drop is consistent with symptoms, we have our answer.

Treatment aims to address the underlying cause, reduce symptoms, and prevent falls or fainting. For many people, simple lifestyle changes are highly effective.

1. Lifestyle and Non-Pharmacological Measures (First-Line Treatment): These are the most important strategies and are often sufficient to control the condition.

• Slow Positional Changes: This is the most important habit to adopt. Always move slowly from lying to sitting and from sitting to standing.
• Increase Fluid Intake: Staying well-hydrated is crucial. Aim to drink 2-2.5 liters of water and other non-alcoholic fluids per day, and more in hot weather.
• Increase Salt Intake: This is one of the few conditions where a doctor might recommend more salt. Salt helps your body retain water, which increases blood volume. This should only be done under a doctor’s guidance, especially if you also have high blood pressure or heart failure.
• Compression Garments: Wearing thigh-high or waist-high compression stockings, or an abdominal binder, can help prevent blood from pooling in the legs and abdomen when you stand.
• Physical Counter-maneuvers: When you feel symptoms starting, you can perform simple maneuvers to raise your blood pressure, such as crossing your legs, tensing your leg muscles, or clenching your fists.
• Dietary Changes: Avoid large, carbohydrate-heavy meals, as they can divert blood to your digestive system and lower blood pressure. Alcohol should also be avoided as it can worsen orthostatic hypotension.

2. Medication Review: A doctor will carefully review all of your medications and may adjust dosages, change the timing, or switch to a different drug if a medication is thought to be contributing to the problem.

3. Pharmacological Treatment: If lifestyle measures are not enough to control the symptoms, a doctor may prescribe medication.

• Fludrocortisone: A medication that helps the body retain more salt and water, thereby increasing blood volume.
• Midodrine: A medication that causes blood vessels to constrict, which helps to raise blood pressure upon standing.

Orthostatic hypotension, the dizzying sensation that occurs when you stand up, is a common condition that can range from a fleeting annoyance to a serious risk factor for falls and injury. It is caused by a temporary failure of the body’s automatic systems to maintain adequate blood pressure to the brain against the force of gravity. While it can sometimes signal a serious underlying neurological or cardiac condition, it is often caused by reversible factors like dehydration or medication side effects. For most people, a combination of simple yet powerful lifestyle strategies such as moving slowly, staying hydrated, and using compression garments can dramatically reduce symptoms and improve safety.

• American Heart Association. (2023). Orthostatic Hypotension. Retrieved from https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/orthostatic-hypotension
• Mayo Clinic. (2023). Orthostatic hypotension (postural hypotension). Retrieved from https://www.mayoclinic.org/diseases-conditions/orthostatic-hypotension/symptoms-causes/syc-20352548
• National Institute of Neurological Disorders and Stroke (NINDS). (2023). Orthostatic Hypotension. Retrieved from https://www.ninds.nih.gov/health-information/disorders/orthostatic-hypotension