Noticing your dog’s heart beating unusually fast while they are resting can be unsettling. While some causes are harmless and temporary, others may signal an underlying health issue that deserves attention.
Understanding why a dog’s heart rate increases at rest can help you decide when to monitor at home—and when to call the vet.
❤️ What Is a Normal Resting Heart Rate for Dogs?
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Small dogs: 90–140 beats per minute
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Medium dogs: 70–120 beats per minute
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Large dogs: 60–100 beats per minute
If your dog is calm, lying down, and not overheated, a heart rate well above these ranges may be abnormal.
🔍 Common Reasons a Dog’s Heart Beats Fast at Rest
1. Stress or Anxiety
Even when lying still, dogs may experience stress from noise, separation, or unfamiliar environments—causing a racing heart.
2. Dehydration or Illness
Fever, dehydration, infection, or pain can force the heart to work harder, even during rest.
3. Overheating
Dogs do not sweat like humans. If they’re warm or recently exposed to heat, the heart rate may stay elevated.
4. Heart or Lung Conditions
Conditions such as heart disease, arrhythmias, or lung problems can cause persistent rapid heartbeat—even when the dog appears calm.
5. Anemia or Low Oxygen Levels
When oxygen delivery drops, the heart compensates by beating faster.
🚨 When to Call the Vet Immediately
Seek veterinary care if rapid heartbeat is accompanied by:
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Weakness or collapse
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Pale or blue gums
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Difficulty breathing
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Coughing or fainting
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Lethargy or refusal to eat
These signs can indicate a medical emergency.
🏠 What You Can Do at Home
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Keep your dog cool and hydrated
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Reduce stress and noise
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Observe breathing rate while sleeping
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Avoid strenuous activity
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Record episodes to share with your vet
🧠 Final Thoughts
A fast heart rate at rest doesn’t always mean danger—but it should never be ignored, especially if it happens repeatedly or with other symptoms. Early evaluation can make a significant difference.