Lethargy in Dogs

While not an illness on its own, lethargy in dogs can be a serious concern for dogs and owners alike. What does it mean if your dog is laying down more often? Is there a problem if they are less enthusiastic about exercise? Can lethargy be normal? Learn more about the causes behind lethargy in dogs, and how you can help get your pup feeling better.

What Is Lethargy in Dogs?

Lethargy is a very general term that can have several meanings. Often, a dog that is lethargic is one that seems as if it has less energy or interest than normal. Your dog may be quieter than usual, not want to participate in regular activities, or may sleep all the time. Lethargy may also cause a dog to change their eating or drinking habits. They may be reluctant to stand or move, or may flinch when handled. Lethargy can be short-term, under 24 hours in duration, or long term, lasting several days or months.

If you’ve brought your dog into the vet for lethargy, you may have heard some terms such as ADR, or BAR, and wondered what they mean. ADR, or “ain’t doing right” is a general statement when the cause of a pet’s illness is unknown upon arrival. It’s generally written down when there is an owner concern about a problem that needs to be figured out.

Terms like BAR (bright, alert, responsive) and QAR (quiet, alert, responsive) can also be used to note down the alertness and lethargy levels of your dog. These tools help your vet determine how your dog is doing, and if their lethargy, vitals, and other symptoms are changing or stable.

Signs of an Emergency

While general lethargy doesn’t always signal an immediate cause for concern, there are some symptoms associated with it that should warrant an immediate trip to your vet. These include visible wounds or bleeding, pale or blue gums and tongue, and lethargy that lasts more than 24 hours. Other symptoms of something serious include pain when being touched or refusing to eat or drink for more than 24 hours.

General symptoms such as vomiting, diarrhea, coughing, etc that last more than 24 hours in addition to lethargy should be seen right away as well. Lastly, if your dog appears listless, confused, comatose, or experiences a seizure, you should seek emergency care right away.

Lethargy in Dogs — Causes

Here are some of the most common causes of lethargy in dogs, both medical and behavioral:

Stress and Anxiety

Stress and anxiety, while not specific diseases, can affect your dog’s health and activity level. You may spot changes in your dog’s behavior generally, including lethargy. Other symptoms include changes in eating and drinking habits, loss of interest in regular activities, and sleeping too much or too little. Dogs may also exhibit “bad” behaviors, such as chewing items they shouldn’t, howling, barking, or acting aggressively, or bouts of hyperactivity followed by exhaustion. If you notice your dog exhibiting signs of stress or anxiety, a vet visit is a good first step.

After you’ve ruled out any potential health issues with your vet, it’s best to address the underlying cause of the stress. Look for changes in your routine or situation, such as moving, a new pet or person, or a change in your working habits. Simple solutions, such as creating or sticking to a daily routine, can help your dog settle back in. Pheromone collars and diffusers can also help. Other tools such as puzzle toys and quiet white noise can help distract your dog from the stressful situation.

In severe cases, additional help may be needed. This may include medication from your veterinarian such as sedatives or anti-anxiety medications, or a training regime from a veterinary behaviorist or animal behaviorist. A combination of behavior modification, positive reinforcement, and medication can help your dog to relax and return to normal behavior.

It can be hard to prevent stress, however preemptive medications before a large change such as a plane flight or move can help. In addition, preparing by training for new situations, such as bringing baby toys into the home before a baby arrives, or providing distraction before the stressful situation can help reduce the amount of stress and anxiety your dog experiences.


With allergies, you may think of the most common symptoms first; sneezing, coughing, runny eyes or nose, or itchy bumps on the skin. However, lethargy can also be a symptom of both allergies and allergy medications. If you notice your dog isn’t as active as they were before and is also experiencing allergy-like symptoms, this could be why. Trouble breathing due to congestion and increased nasal discharge may also make your dog more lethargic or easier to tire out.

Allergies are often diagnosed by exclusion of other issues. Your vet will perform an exam and may recommend tests such as skin scrapings of problem areas, general blood work to rule out anything systemic, and a complete history. Things like reactions happening after going outside, coming into contact with dust, or changing to a new food can all point to allergies as a cause. From there, your vet may recommend conservative treatment such as a daily over the counter medication like Benadryl, Claritin, or Zyrtec, or a switch to a hypoallergenic food.

In some cases, allergy medications can increase drowsiness and lethargy in dogs. This can be a temporary symptom that usually resolves after a few days to weeks of treatment. However, if your dog is experiencing extreme lethargy to the point of not wanting to eat or drink or participate in normal activities, it’s time to talk to your vet. Many newer allergy medications, both over the counter and prescription, such as Atopica and Apoquel, have reduced lethargy side effects. You may need to try several medications before you find the right combination of symptom relief with minimal issues.

Joint Disease

While you may think of joint disease as a condition in older dogs, it can affect dogs of any age. Large breeds are prone to issues such as panosteitis, or “growing pains” that can cause severe pain and joint swelling and mobility issues. Many large breeds, such as retrievers and shepherds, are also prone to genetic issues like elbow and hip dysplasia. Smaller breeds can have genetic problems with the knees (luxating patellas). As dogs age, degenerative joint disease (DJD), arthritis, and general wear and tear can also cause issues.

Symptoms of all joint issues can include lethargy or reluctance to move. Your dog’s gait may change or they may limp or not want to put weight on a specific limb. The limb itself can appear out of place or dislocated, or the joint may be red, swollen, or inflamed. Visual inspection, palpation, and manual movement of the joints can look for obvious problems. In addition, X-rays of the affected joint can look for inflammation, injury, or degeneration of the joint.

Conservative treatment is usually the first line of defense and involves strict kennel rest for 1-2 weeks along with pain and anti-inflammatory medication. From there, your vet may recommend additional treatment or testing. Long-term NSAIDs, such as Rimadyl or Galliprant can help with pain. Supplements like glucosamine and chondroitin, along with newer products such as MSM, green-lipped mussel, and fish oils can also help.

In the case of genetic or severe joint problems, surgical treatment may be needed. This can help to repair the joint and stabilize it to prevent further injury. In breeds with suspected genetic issues, early treatment with joint-supporting supplements can help reduce problems later in life. Spaying/neutering dogs with elbow or hip dysplasia can also prevent passing on the disease to offspring.

General Aging

The senior years can lead to our dogs “slowing down”, which may be interpreted as an increase in lethargy. Older dogs may sleep more, be less active, or be more reluctant to move than when they were puppies or young adults. They may also become more easily confused, bump into things, or be fearful of new situations. Luckily, some of this decline in old age can be reduced or prevented.

Lethargy in Dogs 2A good first step is to rule out any health issues that can cause an older dog to slow down. Metabolic illness, joint diseases, poor diet and exercise, and more can all make your dog painful or reluctant to get around. Many older dogs respond well to medications to treat these conditions. In addition, your vet may recommend specific diet changes, such as a senior diet that includes joint supplements, or a prescription “brain” diet to reduce cognitive decline.

Lifestyle changes at home can also help. Providing ramps up to couches or beds can reduce wear on the joints. Adding in night lights can help with bumping into objects or confusion if your dog’s eyesight is changing. Making louder vibrations or announcing yourself can reduce startling in dogs losing their hearing. And, as with younger dogs, regular exercise can help keep the joints in shape and reduce obesity.

Illnesses and Diseases

Many illnesses and underlying conditions have lethargy as a symptom. Since lethargy is so vague, it is best to look for other signs in addition. This can help pinpoint the cause behind your dog’s illness. Other symptoms to watch out for include changes in eating and drinking habits, vomiting and diarrhea, pain or reluctance to move, weight changes, and fever. In more serious cases, confusion and coma may also be symptoms. These should be seen by a vet or emergency clinic right away.

There are many steps your vet can take to diagnose an underlying illness. A general exam and bloodwork, including a CBC (Complete Blood Count), metabolic panel, and urinalysis are a good baseline. From there, your vet may request more specific tests. X-rays and ultrasound can check for issues with the internal organs, joints, and bones. Depending on the cause, your vet may also recommend a referral to a specialist, such as an oncologist for cancers, or an internal medicine specialist for rare or hard-to-treat conditions.

Treatment can vary. Daily medication can treat symptoms in chronic conditions. Surgical removal of tumors or hospitalization and IV fluids along with medications are the best options for severe illness. As with allergies, some medications may cause a temporary increase in lethargy or weakness, however, these symptoms usually resolve with discontinuation of the medication and are not long-term.


Both systemic infections and abscesses (infections under the skin) can lead to lethargy in dogs. This can be due to an increase in pain, the body using its resources to fight off the infection, or from a change in eating and drinking habits reducing energy.

In addition to lethargy, you may see other signs. With abscesses, this can include a wound that is visibly weeping debris, a spot that is painful or hot to the touch, or an area that is rapidly changing or swelling. With systemic infection, your dog may vomit or have diarrhea, may be feverish, and may be reluctant to get up or move.

Abscesses are generally found via visual inspection, however, your vet may also recommend taking a sample of the area to look at under a microscope or send to a lab. This can help determine the exact cause of the abscess. Lab results can also help determine the best antibiotics to use in the case of an abscess that is slow to heal or unresponsive to medications.

For systemic infections, bloodwork will usually point to the issue. This can include an increase in white blood cells and other immune cells that protect the body and fight against viral and bacterial infiltrators. The types of white blood cells present can also help determine the type of infection going on, and rule out issues such as inflammation or medications affecting it.

Treatment involves antibiotics in the case of bacterial infections. For surface wounds, cleaning, suturing, and placing a drain can also help speed up the healing process. In severe systemic illness, your vet may also recommend injected or IV antibiotics, fluids, and other medications to help resolve symptoms such as vomiting and diarrhea in addition to the infection.

Anemia and Blood Loss

Blood is important for keeping your dog healthy. It provides nutrients to the cells, oxygen via red blood cells, and immune protection with white blood cells. When your dog loses that blood, either through injury or the body’s own destruction of cells, a variety of problems can occur, including lethargy. In the case of an injury, you may notice a visible wound. Internal bleeding or cell destruction can be less apparent until it is very severe. You may notice your dog has a pale nose or gums. They may also be less active, act painful, or change their eating or drinking habits.

Visual examination and bloodwork are the top ways to check for anemia. A CBC will check the number of red and white blood cells. Your vet will also perform a packed cell volume (also known as a hematocrit), or PCV count that checks the percentage of red blood cells and plasma to the total volume of blood. If that percentage is low, it can indicate anemia or dehydration, which should be treated. Additional blood work can look for inflammation and immune markers that indicate problems such as immune-mediated anemias, where the body attacks its own blood cells.

Treatment depends on the underlying cause and severity of anemia. For wounds, stopping bleeding is the top priority. Treating internal injuries and bleeding can also help reduce blood loss. IV fluids and blood transfusions can help replace lost blood, nutrients, and fluid. Prednisone and other steroids can help with an inflammatory or immune system response, while medications such as Erythropoietin can be used to help the body replace lost red blood cells. In addition, supplements such as Vitamin K, A, and B can help with clotting and the production of blood.

Organ Dysfunction

Organ dysfunction, such as kidney or liver failure, can be hard to spot until your dog is very ill. Symptoms may come on gradually, or suddenly, depending on the severity of the situation. You may notice your dog is slowing down or more lethargic. They may also have changes in behavior. These include excessive thirst and urination or changes in weight even without a change in diet or exercise. Dogs may also vomit or not want to eat. More serious symptoms include seizures, difficulty balancing, and confusion.

A combination of symptom history and tests are useful for determining organ dysfunction. Your vet may ask you to monitor your dog’s food intake, weight, urine volume, and amount of water ingested to see if it is gradually increasing. Blood work, such as a CBC, urinalysis, and metabolic panel can help narrow down the cause. With kidney issues, the urine may be overly dilute. Blood work can check for markers that indicate liver or kidney problems.

Treatment depends greatly on the severity of the disease and any other underlying issues. Medications can sometimes worsen kidney or liver problems. A swap to a different medication that is metabolized differently may help. Regular IV or subcutaneous fluid treatment can also help the kidneys flush toxins more easily and reduce strain. Finally, supplements in addition to prescription medications, such as milk thistle, can help support the liver and reduce symptom severity.

Metabolic Illness

Metabolic illnesses have a lot of symptom overlap with other problems, such as organ dysfunction, including lethargy. A lot of the same systems are governed by the hormones and processes of the body, so failure in one can lead to a cascading effect in the other. In addition to symptoms such as lethargy, changes in appetite and thirst, vomiting and diarrhea, weight changes, and more, you may also spot skin and coat changes, hair loss, or behavioral changes.

As with other systemic issues, blood work and examination are key. Besides a general CBC and urinalysis, your vet will likely order specific tests if a metabolic illness is suspected. Free T4, TSH, and other thyroid tests can look for hypothyroidism, which is most common in dogs. ACTH-stim tests and low-dose dexamethasone tests can help rule out problems such as Cushing’s and Addison’s. Glucose tests, either single readings or a day-long panel, can check for diabetes.

Luckily, most metabolic issues can be treated with daily medication. This includes thyroid medications such as thyroxine, steroids such as prednisone or trilostane for Cushing’s, and insulin or diet changes for diabetes. Your vet will also want to do follow-up blood work every 3-6 months. This helps determine how well the medication is working, and also allows for any minute dosing changes as needed.


Another major cause of increased lethargy in dogs is cancer. Cancer cells are huge energy drains and take needed nutrients from the rest of the body in order to grow. In addition, painful tumors can tire your dog out or make them not want to eat or drink, compounding the problem. You may also notice symptoms such as visible tumor growth, limping or favoring a limb, or protecting the abdomen. In severe cases, such as splenic tumors, your dog may become suddenly pale, pant heavily, and become extremely lethargic or unresponsive.

Visible growths should always be checked by your vet. They can take a fine needle aspirate or biopsy of the growth and look at it under a microscope to determine cell type. For internal cancers, X-rays and ultrasound can detect tumors on the liver, lungs, spleen, and bones. Blood work can check for anemias and white blood cell changes that can indicate blood-borne cancers like leukemia.

Treatment can be difficult, depending on the severity of the cancer. If it has spread, or metabolized, to other sections, a referral to a veterinary oncologist is best. They can utilize a wide variety of treatments such as tumor removal, chemotherapies, and supportive care. For tumors that have not spread, surgical removal can prevent them from worsening.

Lethargy can be a scary symptom, especially if your dog is showing other signs of illness. It can be hard to figure out what is going on since lethargy is an overlapping symptom with many causes. If you’re unsure if your dog is lethargic, a symptom journal can help you track symptoms and activity levels. Looking for specific issues in addition to lethargy, and seeking out veterinary care from your local vet can help get your dog feeling better fast.