Heart Racing? Why Your Potassium Is Dangerously High (Hyperkalemia) — and What to Do Next

If your heart feels like it's racing, skipping beats, or pounding in your chest — and you've been told your potassium is high — you may be dealing with hyperkalemia.

Hyperkalemia means there is too much potassium in your blood. Potassium is an essential mineral that helps your:

• Heart beat normally
• Muscles contract
• Nerves send signals
• Cells maintain proper fluid balance

But when potassium levels rise too high, it can interfere with your heart's electrical system. That's when symptoms like a racing or irregular heartbeat can happen — and why hyperkalemia can sometimes become serious.

Let's break this down clearly and calmly so you understand what's happening and what medically approved next steps look like.

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What Is Hyperkalemia?

Hyperkalemia occurs when blood potassium levels rise above the normal range (generally above 5.0 mEq/L, though ranges may vary slightly by lab).

Your kidneys normally keep potassium levels balanced by removing excess amounts through urine. When that system is disrupted, potassium builds up.

Mild elevations may cause no symptoms at all.
More significant elevations can affect your heart rhythm — which is why hyperkalemia is taken seriously in medicine.

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Why High Potassium Can Make Your Heart Race

Your heart runs on electrical signals. Potassium plays a major role in controlling those signals.

When potassium levels are too high:

• The electrical system of the heart becomes unstable
• Signals may travel abnormally
• Heart rhythms can become irregular
• The heart may beat too fast, too slow, or unpredictably

Some people describe it as:

• Fluttering in the chest
• Skipped beats
• A pounding sensation
• Sudden weakness
• Lightheadedness

In severe cases, hyperkalemia can cause dangerous heart rhythm disturbances. That's why doctors treat elevated potassium levels carefully — especially if symptoms are present.

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Common Causes of Hyperkalemia

Hyperkalemia doesn't happen randomly. It usually develops because something interferes with how your body handles potassium.

1. Kidney Disease (Most Common Cause)

Your kidneys remove extra potassium. If they aren't functioning well — due to chronic kidney disease or acute kidney injury — potassium can accumulate.

2. Certain Medications

Some commonly prescribed medications can raise potassium levels, including:

• ACE inhibitors
• ARBs
• Potassium-sparing diuretics
• NSAIDs (in some cases)
• Certain blood pressure medications
• Some heart failure medications

These medications are often important and life-saving — but they require monitoring.

3. Excess Potassium Intake (Less Common Alone)

It's rare for diet alone to cause hyperkalemia in people with normal kidney function. However, potassium supplements or salt substitutes can contribute, especially if kidney function is reduced.

4. Uncontrolled Diabetes

High blood sugar can shift potassium out of cells and into the bloodstream.

5. Severe Dehydration or Illness

Certain acute illnesses can temporarily disrupt potassium balance.

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Symptoms of Hyperkalemia

Mild hyperkalemia often causes no noticeable symptoms.

As potassium rises, symptoms may include:

• Heart palpitations or racing heartbeat
• Muscle weakness
• Fatigue
• Nausea
• Tingling sensations
• Chest discomfort
• Shortness of breath
• Feeling faint

Severe hyperkalemia can cause life-threatening heart rhythm disturbances.

If you experience:

• Chest pain
• Severe weakness
• Fainting
• Severe palpitations

You should seek immediate medical attention.

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How Doctors Diagnose Hyperkalemia

Diagnosis is straightforward:

• Blood test to measure potassium level
• Electrocardiogram (ECG or EKG) to check heart rhythm

Sometimes a repeat blood test is done to confirm results, since lab errors (like blood cell breakage during collection) can falsely elevate potassium.

Doctors will also look for:

• Kidney function test results
• Medication list
• Underlying medical conditions

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Medically Approved Next Steps for Hyperkalemia

Treatment depends on how high your potassium is and whether symptoms or ECG changes are present.

If Potassium Is Mildly Elevated (and Stable)

Your doctor may:

• Review and adjust medications
• Recommend temporary dietary changes
• Monitor levels closely
• Address dehydration
• Treat underlying causes

Many mild cases resolve with simple adjustments.

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If Potassium Is Moderately to Severely Elevated

More urgent treatment may be needed. In hospital settings, doctors may use:

• Calcium (IV) – to protect the heart
• Insulin with glucose – to move potassium back into cells
• Beta-agonist inhalers – to lower potassium temporarily
• Diuretics – to help remove potassium
• Potassium-binding medications – to eliminate potassium through the gut
• Dialysis – in severe kidney failure cases

These treatments are well-established and medically approved.

The goal is to:

1. Protect the heart
2. Lower potassium safely
3. Identify and correct the underlying cause

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Should You Change Your Diet?

If you have hyperkalemia — especially with kidney disease — your doctor may recommend moderating high-potassium foods such as:

• Bananas
• Oranges
• Tomatoes
• Potatoes
• Avocados
• Spinach
• Salt substitutes

However, do not drastically eliminate foods without medical guidance. Many high-potassium foods are otherwise healthy. The approach must be individualized.

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When Is Hyperkalemia an Emergency?

Hyperkalemia becomes urgent when:

• Potassium levels are significantly elevated
• ECG changes are present
• You experience heart rhythm symptoms
• You have severe kidney disease

Because potassium directly affects heart rhythm, doctors do not ignore high levels.

If you are feeling heart racing, weakness, or chest discomfort and know your potassium is high, seek urgent medical care.

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What You Can Do Right Now

If you suspect hyperkalemia or were recently told your potassium is elevated:

• ✅ Review your medications with your doctor
• ✅ Stay hydrated (unless fluid restricted)
• ✅ Follow lab monitoring recommendations
• ✅ Avoid starting supplements without approval
• ✅ Do not panic — but do take it seriously

If you're experiencing symptoms and wondering whether they could be connected to high potassium levels, Ubie's free AI-powered Hyperkalemia symptom checker can help you understand your risk and prepare important information before your doctor's appointment.

This can help you organize your symptoms — but it does not replace medical care.

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The Good News

Hyperkalemia is:

• Common
• Well understood
• Highly treatable
• Closely monitored in medical care

Most cases are managed successfully once identified.

The key is early detection and appropriate follow-up.

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When to Speak to a Doctor

You should speak to a doctor promptly if:

• You've been told your potassium is high
• You have kidney disease
• You take medications that affect potassium
• You feel heart palpitations or weakness
• You have diabetes with abnormal labs

Seek emergency care immediately if you experience:

• Chest pain
• Fainting
• Severe shortness of breath
• Severe or persistent heart rhythm changes

Because hyperkalemia can affect the heart, anything that feels potentially life-threatening should be evaluated urgently.

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Final Takeaway

If your heart is racing and your potassium is high, hyperkalemia may be the cause — and it's something doctors take seriously for good reason.

Potassium is essential for life. But too much can disrupt your heart's rhythm.

The solution is not fear — it's proper medical evaluation, monitoring, and treatment.

Take symptoms seriously.
Stay informed.
And most importantly, speak to a doctor about any abnormal lab result or concerning symptom.

Early care makes hyperkalemia manageable — and often completely reversible.