Lethargy in Dogs: When To Worry

Updated Jan. 30, 2025
lethargy in dogs; a dog sleeps by the window.

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In This Article

What Is Dog Lethargy?

Lethargy in dogs is a symptom that can occur with several health issues in pups.

Let’s look at all that you need to know about lethargy in dogs, from how to tell lethargy apart from tiredness, possible causes, and when to call your vet.

Key Takeaways

  • Lethargy in dogs looks like they are not feeling well. Lethargic dogs sleep more, don’t participate in normal activities, move slower, and hide.
  • Lethargy in dogs can be caused by several medical and physical conditions, making it difficult to know what the underlying cause.
  • Your vet may offer specific treatments such as pain medicine, fluids if your dog is dehydrated, antibiotics to treat lethargy in dogs.

What Is Dog Lethargy?

Lethargy in dogs is a lack of energy and enthusiasm.

But what does that mean for your dog?

It's an important distinction to know if your dog is truly lethargic (which could indicate a medical issue) or is just tired. It may be difficult to make that distinction, but you know your dog better than anyone. Recognizing when your dog is lethargic and being proactive helps your veterinarian give your dog the best care.

A dog that is lethargic is unusually inactive and not interested in getting up and doing normal activities. The severity of lethargy can vary but ranges from just moving more slowly to really having no interest in walks or play.

If you are concerned that your dog is lethargic and not acting like they typically do, call your vet to get them checked out sooner rather than later.

A tired dog may just be sleeping but is easily roused and ready to pop up if they hear a bag of treats or the jingle of the leash. If you have a good explanation for your dog to be tired, then that may be the case.

If you have taken a very long walk or had a large amount of exercise (especially in the heat), then your dog may sleep for hours afterward. If your dog has been at day care or a boarding kennel, they may be excited and on alert most of the time there and then come home and just crash.

If there is no unusual activity or exertion that would cause your pet to sleep more or be acting more tired than usual, then you may be dealing with lethargy, and your dog may need veterinary attention.

What Causes Lethargy in Dogs?

There are several possible causes of lethargy in dogs. A few common reasons a dog may be lethargic include:

Symptoms of Lethargy in Dogs

Lethargy in dogs is almost always a secondary symptom of a primary underlying condition. If your dog is lethargic, it’s most likely not the only symptom of illness they have.

Typically, a lethargic dog will be a less active version of their normal selves with other signs of illness.

However, lethargy in dogs might also be the only symptom visible to pet parents. Once your veterinarian performs a physical exam and runs some diagnostic testing, more symptoms usually arise.

Symptoms of lethargy include:

  • Sleeping more

  • Hiding in places they do not normally frequent

  • Moving slower than normal

  • Not as active as usual even with favorite toys or playtime

  • Uninterested in normal activities such as meals or daily walks

  • Slow to react to stimuli

  • Not acting like themselves

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When Is Dog Lethargy an Emergency?

If you are concerned that your dog is lethargic and not acting like they typically do, call your vet to get them checked out sooner rather than later.

Take your dog to the veterinarian immediately if they are lethargic and have any of the following symptoms:

Treatment for a Lethargic Dog

Your veterinarian will first perform a physical exam.

Once they find where the problem may be coming from, they will recommend diagnostic tests, usually starting with blood work and X-rays.

These tests will help the vet do a thorough check of all body systems and determine if there is something serious going on with your dog’s internal organs.

Your vet may offer specific treatments such as pain medicine, fluids if your dog is dehydrated, antibiotics (commonly Clavamox and Doxycycline) if there’s an infection, or anti-nausea medicine (such as Cerenia or Ondansetron) if your dog is vomiting.

Unfortunately, lethargy is not often something you can remedy at home. This is because a pet parent will not know the root cause of a dog’s lethargy.

Until you can see a vet, keep your pup in a calm, quiet place under your direct supervision, ensuring they have access to food and fresh water (if they are able to tolerate it).

Seek treatment early. Do not wait until your pup is severely ill and it becomes an emergency.

Lethargy in Dogs FAQs

Why is my dog lethargic all of a sudden?

Lethargy in dogs can be caused by several medical and physical conditions, making it difficult to know what the underlying cause.

If your dog is lethargic, seeking veterinary attention for an exam and diagnostic testing is advised.

What can I give my lethargic dog?

If your dog is lethargic, giving them some TLC along with their favorite meal or treat.

This can help entice their appetite and behavior.

All over the counter medications should be approved by your veterinarian before giving them to your dog.

What does lethargy look like in dogs?

Lethargy in dogs looks like they are not feeling well. Lethargic dogs sleep more, don’t participate in normal activities, move slower, and hide.


Stephanie Lantry, DVM

WRITTEN BY

Stephanie Lantry, DVM

Veterinarian

Dr. Lantry is a Milwaukee, Wisconsin native. She knew from a very young age that she wanted to be a veterinarian and worked towards that...


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