How Heat Affects Your Dog’s Heart Health (And How to Protect Them)

Summer is a time for outdoor fun, but rising temperatures can put serious stress on your dog’s heart, especially if they already have a heart condition. Whether your dog is healthy or living with heart disease, understanding how heat affects their cardiovascular system is essential.

Below, Coast to Coast Cardiology explores this important topic and describes the steps you can take to protect your dog’s heart health in hot weather.

How Heat Impacts Your Dog’s Heart

Dogs don’t sweat like humans do. They regulate their body temperature through panting and limited sweating via paw pads. When temperatures rise, this natural cooling system becomes less effective.

To compensate, your dog’s heart has to work harder, pumping faster to circulate blood and dissipate heat. This increased workload can be risky, especially in:

  • Dogs with pre-existing heart conditions (like mitral valve disease or cardiomyopathy)
  • Senior dogs or overweight dogs
  • Brachycephalic breeds (like Bulldogs, Pugs, and Boxers)
  • Dogs on cardiac medications that affect blood pressure or hydration

Heat stress can quickly escalate to heatstroke, a life-threatening emergency that often causes arrhythmias, low blood pressure, and even sudden cardiac arrest.

Signs Your Dog’s Heart Is Struggling in the Heat

  • Excessive panting or drooling
  • Increased heart rate or breathing rate
  • Weakness, staggering, or collapse
  • Pale or bluish gums
  • Coughing or difficulty breathing
  • Lethargy or refusal to walk

If your dog shows any of these symptoms, move them to a cool area immediately and call your veterinarian.

Vertebral Heart Scale in a Cat With a Grade III-IV/VI Murmur

5 Ways to Protect Your Dog’s Heart in Hot Weather

1. Avoid Peak Heat Hours

Walk your dog early in the morning or after sunset when temperatures are cooler.

2. Always Provide Fresh Water

Dehydration puts extra strain on the heart and can worsen heart disease symptoms. Make sure your dog always has access to clean, cool water.

3. Know Your Dog’s Risk Level

If your dog has been diagnosed with a heart condition like congestive heart failure, DCM, or MMVD, ask about specific heat precautions.

Some dogs may need:

  • Medication adjustments
  • Reduced exercise
  • Regular temperature monitoring during activity

4. Never Leave Your Dog in a Parked Car

Even with the windows cracked, a parked car can reach deadly temperatures in minutes. Dogs with heart conditions are even more vulnerable to sudden heatstroke and heart failure.

5. Use Cooling Tools Safely

Cooling vests, mats, and shaded areas can help regulate your dog’s body temperature. But never use ice-cold water on an overheated dog—it can shock the system and worsen heart strain. Gradual cooling is safest.

Is Your Dog at Risk for Heart Problems?

If your dog has a heart murmur, trouble breathing is on heart medication, or is just getting older, our veterinary cardiology team can help you build a custom summer safety plan.


Vertebral Heart Scale in a Cat With a Grade I-II/VI Murmur

If you have any worries about your pet’s heart health, come see us! At Coast to Coast Cardiology, we have 12 distinct locations, but we deliver on one goal no matter what: treating the patient, not just the signs. To schedule an appointment, contact us online or call 844-582-3827 today.