Dizzy When Standing? Why Your Heart Is Racing & Medical Next Steps

Feeling dizzy when you stand up—especially if your heart starts racing—can be unsettling. For some people, it happens occasionally. For others, it's frequent and disruptive. While it's often caused by a temporary drop in blood pressure, persistent symptoms may point to conditions like POTS (Postural Orthostatic Tachycardia Syndrome) or vasovagal syncope.

Understanding what's happening in your body is the first step toward getting the right help.

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Why You Feel Dizzy When You Stand

When you move from sitting or lying down to standing, gravity pulls blood toward your legs and abdomen. Normally, your body responds quickly:

• Blood vessels tighten
• Heart rate increases slightly
• Blood pressure stabilizes
• Blood flow to the brain stays steady

If this adjustment doesn't happen properly, less blood reaches your brain for a short time. That's when you may feel:

• Lightheaded
• Dizzy
• Faint or close to fainting
• Blurry vision
• Weak or shaky
• Nauseated
• Like your heart is pounding or racing

The sensation usually lasts seconds to minutes—but recurring episodes deserve attention.

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Why Is Your Heart Racing?

A racing heart when you stand is often your body trying to compensate. If blood pressure drops or circulation shifts too quickly, your heart beats faster to maintain blood flow to the brain.

However, in some people, this response is exaggerated.

One important condition to know about is POTS (Postural Orthostatic Tachycardia Syndrome).

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What Is POTS?

POTS is a disorder of the autonomic nervous system—the system that controls automatic functions like heart rate and blood pressure.

In POTS:

• Heart rate increases by 30 beats per minute or more within 10 minutes of standing (40 bpm in teens)
• Blood pressure usually does not drop significantly
• Symptoms improve when lying down

Common symptoms of POTS include:

• Rapid heartbeat upon standing
• Dizziness or lightheadedness
• Fatigue
• Brain fog
• Headaches
• Nausea
• Exercise intolerance
• Shakiness
• Shortness of breath

POTS is more common in women and often begins between ages 15 and 50. It can develop after viral illness, surgery, pregnancy, or periods of prolonged bed rest.

While POTS is not usually life-threatening, it can significantly affect quality of life and requires proper medical evaluation and management.

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Other Possible Causes of Dizziness When Standing

Not all dizziness with standing is POTS. Other common causes include:

1. Orthostatic Hypotension

A drop in blood pressure when standing.

It may be caused by:

• Dehydration
• Blood loss
• Certain medications (blood pressure drugs, antidepressants)
• Diabetes-related nerve damage
• Heart conditions

Symptoms often improve quickly after sitting or lying down.

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2. Vasovagal Syncope

A common cause of fainting triggered by:

• Standing too long
• Heat exposure
• Emotional stress
• Pain
• Seeing blood

Before fainting, people may feel:

• Warm
• Sweaty
• Nauseated
• Pale
• Dizzy

If you're experiencing these warning signs and want to explore whether your symptoms align with this condition, a free AI-powered symptom checker for Vasovagal Syncope can help you understand your symptoms better and prepare for a conversation with your doctor.

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3. Dehydration

Not drinking enough fluids reduces blood volume, making it harder to maintain blood pressure when standing.

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4. Anemia

Low red blood cell levels reduce oxygen delivery to the brain, causing fatigue and lightheadedness.

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5. Heart Rhythm Problems

Irregular heartbeats (arrhythmias) can cause:

• Sudden racing heart
• Skipped beats
• Dizziness
• Fainting

These need medical evaluation.

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When Should You Be Concerned?

Seek urgent medical care if dizziness or a racing heart occurs with:

• Chest pain
• Severe shortness of breath
• Confusion
• Fainting without warning
• Injury from passing out
• A history of heart disease
• Family history of sudden cardiac death

These could signal a serious heart or neurological issue.

If symptoms are recurrent but not severe, schedule a prompt appointment with a doctor for evaluation.

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How Doctors Evaluate These Symptoms

Your doctor may:

Take a detailed history

They'll ask:

• When symptoms started
• What triggers them
• How long they last
• Whether you've fainted
• What medications you take

Perform orthostatic vital signs

This involves measuring:

• Heart rate
• Blood pressure

While lying down, sitting, and standing.

Order tests if needed

These may include:

• Blood tests (for anemia, thyroid issues, dehydration)
• ECG (heart rhythm test)
• Echocardiogram
• Holter monitor (24-hour heart monitor)
• Tilt table test (used to diagnose POTS or vasovagal syncope)

If POTS is suspected, referral to a cardiologist or neurologist familiar with autonomic disorders may be recommended.

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Treatment Options

Treatment depends on the cause.

For POTS

Management often includes:

• Increasing fluid intake (2–3 liters per day unless otherwise directed)
• Increasing salt intake (if recommended by your doctor)
• Compression stockings
• Gradual exercise programs (especially recumbent cycling or rowing)
• Medications in some cases (to regulate heart rate or blood vessel tone)

Improvement can take time, but many people see progress with consistent management.

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For Orthostatic Hypotension

• Treat underlying cause
• Adjust medications
• Stay hydrated
• Rise slowly from sitting or lying down
• Elevate head of bed slightly

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For Vasovagal Syncope

• Avoid known triggers
• Stay hydrated
• Use physical counter-pressure maneuvers (like leg crossing or muscle tightening when feeling faint)

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Practical Steps You Can Take Now

While waiting to see a doctor:

• Stand up slowly
• Avoid locking your knees when standing
• Drink adequate fluids
• Avoid skipping meals
• Limit alcohol
• Track your symptoms (time, triggers, heart rate if possible)

If safe to do so, you can check your pulse before and after standing and share the numbers with your doctor.

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The Bottom Line

Feeling dizzy when standing—especially with a racing heart—is common but not something you should ignore if it's recurring.

In many cases, the cause is manageable. Conditions like POTS are real, diagnosable medical disorders that benefit from proper care. Others, like dehydration or medication side effects, can be corrected relatively easily.

The key is identifying the root cause rather than guessing.

If your symptoms are new, worsening, or interfering with daily life, speak to a doctor promptly. And if you experience chest pain, fainting, or severe shortness of breath, seek emergency care.

Your body is signaling that something needs attention. With the right evaluation and guidance, most causes of dizziness and racing heart upon standing can be treated or significantly improved.