Lethargic Dog: Causes and How to Help

There’s a difference between a couch potato and a lethargic dog. While your couch potato dog may just be a tad lazy, a lethargic dog usually needs medical attention. Luckily, even a low-energy dog can signal to you that they’re not feeling like themselves.  

Find out what canine lethargy is, potential causes, and the steps you should take to help your dog.

What Is Lethargy in Dogs?

Lethargy in dogs is defined as a decrease in energy and activity levels. If your dog is lethargic, you may notice they’re lounging around more than usual, uninterested in play, indifferent to walks, acting sluggish, and/or potentially not as interested in food as they typically would be.

While it’s normal for senior dogs to have a lower energy level than rambunctious puppies, that doesn’t mean that the senior dog is lethargic. Similarly, a low-energy Pug isn’t lethargic just because they don’t have the natural agility of a Border Collie! 

Remember, lethargy involves a decrease in energy and activity compared with the individual dog’s usual baseline. “Lethargic” is not a synonym for “lazy,” “calm,” “reserved,” or “relaxed.”

Why Is My Dog Lethargic? Causes of Canine Lethargy

Your dog could be acting lethargic for a wide variety of reasons. Here, we’ll cover general reasons for a dog acting sluggish:

Infectious Disease

We experience lethargy when we’re sick, and our dogs are no different. Infections are usually bacterial, viral, fungal, or parasitic. Examples of infectious diseases that can cause lethargy in dogs include parvovirus, kennel cough, canine influenza, leptospirosis, heartworms, and hookworms.

Pain

Pain is an important cause of sudden lethargy in dogs. Pain can stem from arthritis, dental disease, injuries, intervertebral disc disease, and more. Unfortunately, your dog cannot easily tell you what hurts. Luckily, veterinarians are accustomed to figuring it out!

Chronic Health Conditions

Many canine health conditions include lethargy as a symptom. Examples include kidney disease, hypothyroidism, Cushing’s disease, diabetes, heart disease, and cancer. Chronic health conditions are generally more common in older dogs but can occasionally occur in young dogs.

Stress and Anxiety

While some dogs become more hyperactive when experiencing stress and anxiety, other dogs act withdrawn. Causes of stress and anxiety could include thunderstorms or fireworks, moving to a new home, a recent veterinary visit, a new pet or person in the home, lack of sufficient exercise or mental stimulation, and more.

Medications

Lethargy is a commonly listed side effect of many medications. Lethargy is often noted after a dog receives pain medications, anxiety medications, or sedatives. It’s also common for a dog to remain lethargic for around a day after undergoing anesthesia. While it’s possible for some antibiotics to make a dog tired, keep in mind that the underlying infection that the antibiotics are treating may also contribute to lethargy.

Vaccinations

Your dog may not feel quite like themself for a day or two after receiving a vaccination. Lethargy, achiness, and low grade fevers are normal side effects of recent vaccination.

Lethargic Dog Symptoms

Other symptoms that occur concurrently with lethargy could indicate that your dog is experiencing a medical issue. Examples of what to watch for include:

• Decreased or lost appetite
• Changes to the amount your dog is drinking
• Increased urination
• Vomiting and diarrhea
• Drooling
• Dropping food or difficulty chewing
• Acting weak or wobbly
• Hunched posture
• Pale or yellow mucous membranes (gums, whites of eyes, genitals)
• Sneezing, discharge from the eyes or nose, and/or coughing
• Difficulty breathing
• Limping

How to Help a Lethargic Dog: Next Steps

If you’re noticing your dog acting lethargic, the first thing you’ll want to do is observe them, taking note of any other symptoms that they’re exhibiting. 

A dog acting lethargic with an obvious cause, such as recent vaccination or taking pain medications after surgery, may not be a cause for concern if they are otherwise still eating and acting okay.

If your dog has been acting lethargic for more than one day, you should contact your veterinarian. They may suggest bringing your pup in for an appointment to rule out pain, infections, and health conditions as causes.

Contact your veterinarian if your dog is experiencing other issues in addition to lethargy, such as vomiting, diarrhea, or limping. You should also contact your veterinarian if you have a lethargic puppy. Puppies are very susceptible to infectious disease and several other causes of lethargy. If your puppy is not eating much and sleeping a lot, talk to your vet.

If your dog is collapsing, has pale or yellow gums, is having difficulty breathing, or is showing any other serious symptoms, seek emergency attention.

If you note any other changes from your dog’s normal behavior, make sure to discuss these with your veterinarian. The more information your veterinarian knows, the easier it will be for them to find out what’s causing your dog’s lethargy.

Diagnostics for Lethargic Dogs

Your veterinarian’s very first step will be to discuss your pet’s history and perform a full examination. The information your veterinarian gathers will drive what diagnostics they perform next. 

Common diagnostics for a dog showing lethargy include:

• Blood and urine tests to look at overall organ function
• X-rays
• Abdominal ultrasound

In puppies and unvaccinated dogs, parvovirus tests are also common for lethargic dogs. 

In some cases, additional testing may be recommended. This would depend on your individual pet’s symptoms and what baseline testing shows.

Treatment for Dog Lethargy

The treatment for your dog’s lethargy will depend on the suspected cause: a dog suspected of having a bacterial infection may be given antibiotics. A dog with diabetes may be started on insulin and a special diet, while a dog with arthritis might start taking pain medication.

Your pet’s overall prognosis depends on the underlying cause. For example, an infection may improve over 10 to 14 days. Dental pain may resolve within a week or two of a professional dental cleaning. Arthritis pain may be controlled after a month or two of consistent treatments but may relapse as the arthritis worsens. Dogs with systemic health conditions like chronic kidney disease may also improve with supportive care but later decline as the condition progresses. Your veterinarian is your best source for what to expect in your pup’s individual case.

Bottom line, if you have any concerns about your dog’s behavior, including decreases in their energy level, it’s important to speak with your veterinarian. Lethargy in dogs generally has an underlying cause and shouldn’t be ignored.