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Jan. 20, 2026

7 causes of low blood pressure and a high heart rate

Sundas Ahmed, MD

Medically reviewed by:
Sundas Ahmed, MD

If you’ve ever noticed low blood pressure and a high heart rate at the same time, it can be unsettling. Sometimes it occurs when you stand up too quickly, but it can also indicate an underlying medical condition that requires attention.

Knowing why these two symptoms occur together is the first step to protecting your health. This article will walk you through the common symptoms of low blood pressure with a fast heart rate, the seven most frequent causes, treatment options, prevention strategies and when it’s time to call your doctor.

What normal blood pressure and heart rate look like

Your blood pressure measures the force of blood against the walls of your arteries. Normal blood pressure is around 120/80 mmHg.1 Low blood pressure, also called hypotension, is usually defined as below 90/60 mmHg.2 Some people feel fine with lower numbers, but others may develop dizziness, fainting or confusion.

Your heart rate (pulse) is how many times your heart beats per minute. A normal resting rate for adults is 60–100 beats per minute.3 Anything over 100 beats per minute at rest is called tachycardia.

Why low blood pressure and a high heart rate happen together

Your body works to protect the brain, heart and other organs. When blood pressure drops, the heart beats faster to keep blood moving. This is called a compensatory response.4

Several things can cause it. If you lose fluids from dehydration or bleeding, there isn’t enough blood to circulate. If your blood vessels suddenly relax and get wider, the pressure inside falls. If your heart is weak and not pumping effectively, your blood pressure can also drop.

When this happens, you may feel dizzy, lightheaded or notice your heart racing. These are signs that your body is working harder to keep oxygen flowing to where it’s needed most.

Symptoms of low blood pressure and high heart rate

You may notice symptoms before you check your numbers.5 Common signs include:

  • Lightheadedness or dizziness.
  • Fainting or feeling like you might pass out.
  • Rapid heartbeat or palpitations.
  • Chest discomfort.
  • Shortness of breath.
  • Blurred vision.
  • Fatigue or weakness.
  • Confusion or difficulty concentrating.
  • Nausea.

If these symptoms occur suddenly or are severe, it’s essential to seek medical attention immediately.

Causes of low blood pressure and a high heart rate

There are several reasons why you may experience an elevated heart rate and low blood pressure simultaneously. Below are the seven most common causes.

1. Dehydration

When your body loses more fluid than it takes in, you become dehydrated. This may occur after a long walk on a hot day, during an illness accompanied by vomiting or diarrhea or if you don’t drink enough water. Older adults are at greater risk because the urge to drink weakens with age, and certain medications, such as water pills, make fluid loss worse.6

Why it causes low blood pressure and high heart rate

With less fluid in your system, the amount of blood circulating in your vessels decreases, resulting in lower blood pressure. To keep blood moving to your brain and other organs, your heart beats faster. This is why dehydration often causes low blood pressure and a high heart rate. Common symptoms include dizziness, fatigue and dry mouth.

Treatment

  • Drinking water or electrolyte-rich fluids can usually treat mild dehydration.
  • Moderate to severe dehydration—especially if you can’t keep fluids down—often requires IV fluids in a clinic or hospital.

Prevention

  • Drink small amounts of water regularly during the day, even if you don’t feel thirsty.
  • Stay hydrated in hot weather, during illness or if you take medication such as water pills (diuretics).
  • Limit alcohol and caffeine.

2. Blood loss (hemorrhage)

Blood loss can happen suddenly after an injury or surgery or gradually from chronic conditions such as ulcers, colon polyps or diverticulosis. Internal bleeding in the stomach or intestines is more challenging to detect, but it still reduces your overall blood volume.

Why it causes low blood pressure and high heart rate

When blood volume drops, blood pressure falls. To keep vital organs like the brain, heart and kidneys supplied with oxygen, your heart speeds up. This is why people with significant blood loss often develop both low blood pressure and a rapid heart rate.

Treatment

  • For external bleeding, apply direct pressure and find immediate first aid.
  • For chronic or internal bleeding, your doctor may order tests such as endoscopy, colonoscopy or imaging.
  • Severe blood loss usually requires emergency care with IV fluids, blood transfusions or surgery.

Prevention

  • Reduce trauma risk by always using seatbelts, helmets and protective equipment.
  • Maintain regular medical care to manage chronic conditions that may lead to hidden bleeding.

3. Shock

Shock is a medical emergency where blood flow is too low to keep your organs alive and working.7 It always requires immediate treatment. There are several types:

  • Hypovolemic shock: from severe blood or fluid loss.
  • Septic shock: from a severe infection.
  • Cardiogenic shock: when the heart is too weak or damaged to pump.
  • Anaphylactic shock is a life-threatening allergic reaction.
  • Neurogenic shock: from specific spinal cord injuries.

Why it causes low blood pressure and high heart rate

In shock, your blood pressure drops sharply because there isn’t enough blood or oxygen reaching your organs. To compensate, your heart rate increases to maintain circulation. Without treatment, organs like the brain, heart and kidneys can quickly shut down.

Treatment

Treatment depends on the cause and may include:

  • IV fluids to restore volume.
  • Oxygen therapy.
  • Medications to raise blood pressure or support the heart.
  • Antibiotics for severe infections.
  • Epinephrine for life-threatening allergic reactions.

Prevention

  • Manage chronic conditions such as diabetes or heart disease.
  • Treat infections early to lower the risk of sepsis.
  • If you have a severe allergy, carry an epinephrine injector and know how to use it.

4. Postural orthostatic tachycardia syndrome (POTS)

POTS is a condition where your nervous system doesn’t regulate blood flow well when you stand.8

Why it causes low blood pressure and high heart rate

Blood pools in your legs when you stand, lowering pressure. Your heart rate rises to compensate.

Treatment

  • Lifestyle adjustments, such as slow position changes.
  • Increased salt and fluid intake.
  • Medications may help in some cases.

Prevention

  • Wear compression stockings.
  • Avoid standing still for long periods.
  • Exercise regularly under your doctor’s guidance.

5. Orthostatic hypotension

Also called postural hypotension, it occurs when your blood pressure drops suddenly after standing up from a sitting or lying position.9

Why it causes low blood pressure and high heart rate:

Standing pulls blood into your legs. In orthostatic hypotension, your blood vessels don’t constrict enough, so your heart rate increases to help maintain circulation.

Treatment

  • Rise slowly from sitting or lying.
  • Drink more fluids.
  • Medications can help regulate pressure.

Prevention

  • Avoid sudden posture changes.
  • Stay hydrated.
  • Use support stockings if recommended.

6. Heart rhythm problems (arrhythmias)

Arrhythmias are conditions that affect the way your heart beats. Instead of a steady rhythm, the heartbeat may be too fast, too slow or irregular.10 One of the most common types is atrial fibrillation (AFib), where the upper chambers of the heart quiver instead of contracting the way they should.11 When this happens, blood doesn’t move through the heart as smoothly as it should.

Why it causes low blood pressure and high heart rate:

If the heart can’t pump in a strong, coordinated way, less blood is pushed out to the rest of your body. This can make blood pressure drop. At the same time, the heart often beats faster in an effort to pump more blood forward. That combination leads to the familiar symptoms many people with arrhythmias describe—racing heartbeat, lightheadedness, weakness or even fainting.

Treatment

The treatment of arrhythmias depends on the type and the severity of the symptoms. Common approaches include:

  • Medications to steady the rhythm or slow the heart rate.
  • Electrical cardioversion, a quick, controlled shock to reset the heart’s rhythm.
  • Ablation, a procedure that targets and removes the heart tissue causing abnormal signals.
  • Pacemakers or implantable defibrillators for people whose hearts need long-term rhythm support.

Prevention

While not every arrhythmia can be prevented, you can lower your risk by:

  • Managing blood pressure, cholesterol and diabetes carefully.
  • Avoiding smoking and limiting alcohol or caffeine.
  • Staying physically active and maintaining a healthy weight.
  • Following up regularly with your doctor if you already have heart disease or thyroid problems.

7. Heart failure

Heart failure, often called congestive heart failure (CHF), happens when the heart muscle becomes too weak or too stiff to pump blood effectively.12 It doesn’t mean the heart has stopped working—it means the heart can’t keep up with the body’s demands. This can occur after years of high blood pressure, coronary artery disease, a heart attack or damage to the heart muscle.

Why it causes low blood pressure and high heart rate

When the heart’s pumping ability declines, less blood is pushed into circulation with each beat. This reduced output lowers blood pressure. To compensate, the body tells the heart to beat faster in an attempt to keep blood flowing to vital organs. People with heart failure may experience fatigue, shortness of breath, leg swelling or a rapid heartbeat, particularly during physical activity or at night.

Treatment

The goal of treatment is to alleviate symptoms, prevent fluid accumulation and safeguard the heart from further damage. Options include:

  • Medications such as diuretics to reduce fluid overload, ACE inhibitors to relax blood vessels and beta-blockers to reduce strain on the heart.
  • Lifestyle changes include a low-sodium diet, daily weight checks to monitor fluid retention, and limiting alcohol.
  • Procedures and devices like implantable defibrillators, biventricular pacemakers or ventricular assist devices for severe cases. In some patients, heart transplantation may be considered.

Prevention

Heart failure often happens gradually. Preventive care makes a big difference. Steps include:

  • Keeping blood pressure, cholesterol and diabetes under control.
  • Avoiding smoking and limiting alcohol.
  • Maintaining a healthy weight and regular physical activity (as recommended by your doctor).
  • Following up regularly with a cardiologist if you already have heart disease.

Other contributing factors

  • Pregnancy: Early pregnancy often lowers blood pressure due to hormonal changes. Your heart rate may rise slightly to maintain circulation. Typically, this is a temporary condition that your doctor will monitor.
  • Medications: Certain medicines, such as diuretics, beta-blockers or antidepressants, may lower blood pressure while affecting heart rate. Always review side effects with your provider.

When to see a doctor

You should make an appointment with your doctor if you have ongoing or frequent episodes of low blood pressure and a high heart rate. Seek care if you also notice:

  • Dizziness or fainting.
  • Chest pain.
  • Shortness of breath.
  • Confusion.
  • Irregular heartbeats.

When to call 911

Call 911 immediately—or have someone nearby call for you—if you experience:

  • Fainting and not waking up quickly.
  • Chest pain, pressure or tightness.
  • Trouble breathing or severe shortness of breath.
  • Signs of shock include cold and clammy skin, confusion or a weak pulse.

If you’re ever unsure whether your symptoms are serious, it’s always safer to call 911 and seek immediate medical attention.

Living with low blood pressure and high heart rate

Managing this condition often involves treating the root cause, and making lifestyle changes can also be beneficial. These include:

  • Drink enough fluids daily.
  • Limit alcohol.
  • Exercise with your doctor’s guidance.
  • Get up slowly from sitting or lying down.
  • Monitor your blood pressure and heart rate at home.

Key takeaways

  • Low blood pressure and a high heart rate can occur together for many reasons, from dehydration to heart problems.
  • Some causes are mild and can be managed at home, but others are medical emergencies.
  • Prevention often focuses on staying hydrated, managing chronic diseases and making slow position changes.
  • Always seek medical care if symptoms are frequent, severe or come on suddenly.

Your health is essential. If you experience symptoms of low blood pressure and a high heart rate, consult your doctor to receive the appropriate treatment and prevent complications.

References

Conditions & diseases Articles