Lethargic Dog: 5 Signs You Need to Call the Vet


Is your dog a couch potato who loves nothing more than belly rubs on the sofa? An exercise fiend who hits the trails or goes on long runs with you? All dogs are different in terms of the amount of exercise they need and the amount of sleep they get. And it’s all good…unless something changes. If your once-energetic dog is suddenly a lethargic dog, something may be up. For example, maybe he’s been extra sleepy in the morning lately instead of bolting out the door as usual for his morning walk. Or he hasn’t been greeting you at the end of the day with his usual tail-wagging exuberance. Lethargy, or a marked lack of energy or enthusiasm, can be a symptom of many different problems, and it’s important to know when you should pick up the phone and call your vet.

How much should your dog be sleeping?

Even if it seems like your pooch is constantly napping in the sunbeams, that doesn’t necessarily mean there’s a problem. Dogs need a lot of sleep. In fact, most healthy adult dogs usually get anywhere from 12 to 14 hours of sleep a day. But that’s just a general rule of thumb. “Many factors influence the sleep requirements in dogs,” explains Kerry Rolph, DVM, Associate Professor of Small Animal Internal Medicine at Ross University School of Veterinary Medicine. “These include breed, gender, and neutering, diet, and frequency of feeding, changes in housing conditions, changes in working routine, activity levels during the day, and age.”

Age is a big factor when determining what’s normal—and it’s probably one of the many things your dog wishes you knew. Puppies, like human babies, need more sleep than their middle-aged compatriots, likely because they’re using so much energy growing, exploring, and playing. On the flip side, as a dog ages, it often becomes less active and sleeps more. “Older dogs demonstrate altered sleep cycles, with decreased REM sleep and increased wakefulness during the night, meaning that older dogs will have poorer quality sleep, and sleep more often during the day,” explains Dr. Rolph. Other than normal aging, here are a few more concerning things that could be making your dog lethargic.


Did you just move? Change your hours at work? Stressors like a schedule shift, new home, new pet, or loss of a long-time pet buddy can impact your dog’s sleep cycle and leave him listless. “Lethargy can arise for a myriad of reasons,” explains Dr. Rolph. “It may be because of an altered sleep pattern, but can also be associated with stressful events, such as loss of a companion or illness.” Whatever the cause, keep an eye on your furry friend’s food intake and water consumption. If you notice a change in appetite or if they aren’t drinking or urinating as much as normal, give your vet a call. Don’t miss these other silent signs your dog may be depressed.


Lethargy or reluctance to exercise is usually the first indicator that your pet is in pain. In younger dogs, torn ligaments in the knees are common, and telltale signs include limping and a reluctance to stand.

An older lethargic dog may be suffering from arthritis, according to the American Kennel Club. Commonly located in the hips, knees, or elbows, osteoarthritis is caused by small areas of degradation in the smooth cartilage lining the joints. Areas of calcification can also develop on the surface of joints. These rough areas, called osteophytes, disrupt the gliding motion typically found in healthy joints. When joints move, the osteophytes rub or grate against the bone and can cause significant pain.

If you think your dog has arthritis, it’s essential to see a vet to get a proper diagnosis and treatment plan. Pain relievers designed for humans, like acetaminophen and ibuprofen, are toxic for dogs and can result in severe GI problems, blood and liver abnormalities, and even death. Your veterinarian can prescribe pain medication designed specifically for dogs that will relieve the pain associated with arthritis and not result in medical emergencies commonly seen when dogs are given human medications. These are some other signs that your dog is in pain.


If your dog is middle-aged or older and seems to be sleeping more and also gaining weight, he may have hypothyroidism. As some dogs age, their thyroid gland doesn’t work as efficiently and produces less thyroid hormone. This deficiency can make your dog lethargic, as well as cause weight gain and hair loss. Once diagnosed, however, treatment is simple: a daily medication and routine follow-ups to check thyroid blood levels. Sometimes it can be hard to tell if your pet has a problem. These 10 signs can indicate your “healthy” dog is showing illness symptoms.


As with humans, diabetes mellitus is a disease caused by insulin insufficiency. Insulin is necessary for the body to utilize glucose (sugar), and without the appropriate levels of insulin, glucose builds up in the bloodstream and can’t be utilized by the cells for energy. Symptoms of diabetes include increased thirst and urination, as well as lethargy, which is a later sign, according to PetMD.

Heart problems

Many different cardiac abnormalities can cause your dog to be lethargic. Valvular dysfunction, for example, means that tissues aren’t getting enough oxygenated blood, and that can lead to lethargy and exercise intolerance. Later symptoms include a lack of appetite, excessive panting, coughing, shortness of breath, and occasionally fainting. By identifying the lethargy as a problem early on, though, you can get the necessary treatment for your pup sooner rather than later.

That’s important no matter what’s ailing your lethargic dog. Note any abnormal behavior, especially if it’s recurring. You know your dog better than anyone, so if they’re sleeping more than usual or just seem uninterested in the things that normally interest them, call your vet and schedule an exam.

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