Lethargy in Dogs: When To Worry

Lethargy in dogs is a lack of energy and enthusiasm that can occur with several health conditions. A lethargic dog may sleep more, move slowly, or lose interest in normal activities.

If your dog is unusually lethargic, contact your veterinarian. Seek immediate veterinary care if lethargy occurs with serious symptoms such as pale gums, difficulty breathing, a distended abdomen, or seizures.

Here’s what pet parents should know about the causes and symptoms of lethargy in dogs, how to distinguish it from tiredness, and when to seek veterinary care.

What Is Lethargy in Dogs?

Lethargy in dogs is a lack of energy and enthusiasm that causes them to become unusually inactive or uninterested in normal activities.

The severity of lethargy can vary but ranges from just moving more slowly to really having no interest in walks or play.

Recognizing when your dog is lethargic and being proactive helps your veterinarian give your dog the best care.

What's the Difference Between a Tired Dog and a Lethargic Dog?

A tired dog may sleep more than usual but is easily roused, while a lethargic dog may remain unusually inactive without a clear reason.

Even while sleeping, a tired dog is 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 dog 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?

Lethargy in dogs can have many causes, including infections, pain, medication side effects, heart disease, kidney disease, injuries, and other underlying medical conditions.

Infections and Parasites

• Infection
  • Viral, bacterial, fungal
  • External parasites (tick disease or fleas)
  • Internal parasites (intestinal worms)

Pain, Injuries, and Medications

• Pain
• New medication or flea/tick prevention
• Injury or trauma

Heart, Respiratory, and Organ Diseases

• Heart disease
• Respiratory disease (pneumonia, bronchitis)
• Kidney disease
• Liver disease

Hormonal and Blood Conditions

• Addison’s disease
• Anemia
• Diabetes
• Hypothyroidism

Other Causes of Lethargy in Dogs

• Neurologic disease
• Stress or anxiety
• Lack of exercise
• Poison or toxin
• Cancer

What Are the Symptoms of Lethargy in Dogs?

Symptoms of lethargy in dogs include sleeping more than usual, hiding, moving more slowly, and showing less interest in normal activities such as meals, walks, or playtime.

Other signs of lethargy in dogs 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

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.

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.

When Is Dog Lethargy an Emergency?

Lethargy in dogs is an emergency when it occurs with serious symptoms such as pale gums, a distended abdomen, difficulty breathing, seizures, or changes in responsiveness.

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

• Pale gum color (can indicate internal bleeding and can lead to life-threatening anemia)
• Distended abdomen (can be a sign of bloat or other abdominal emergencies)
• Labored breathing or blue or purple tongue color (often due to heart or lung problems that need urgent medical attention)
• Stomach upset (vomiting, diarrhea or change in appetite) lasting more than 48 hours
• Shaking/tremors
• Ataxia
• Seizures
• Change in mentation (dull or nonresponsive)

If you are concerned that your dog is lethargic and not acting like they typically do, contact your veterinarian to have them examined as soon as possible.

How Is Lethargy in Dogs Diagnosed and Treated?

Treatment for lethargy in dogs depends on identifying the underlying cause. Your veterinarian may recommend diagnostic testing, medications, fluids, or other treatments based on your dog's condition.

How Veterinarians Diagnose Lethargy in Dogs

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 veterinarian do a thorough check of all body systems and determine if there is something serious going on with your dog’s internal organs.

How Veterinarians Treat Lethargy in Dogs

Your veterinarian 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.

What To Do at Home if Your Dog Is Lethargic

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 veterinarian, 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.