What is lethargy in dogs?

Lethargy means sluggishness, drowsiness or dullness. A dog who’s lethargic may show no interest in going for a walk, even though that’s usually the highlight of their day, or they might not want to play or eat.  Sometimes lethargy in dogs can be due to the weather, perhaps it’s very hot, or being tired out after an extra long walk. But it can also be the first sign that something’s not quite right with your dog.

Lethargy, weakness and sudden tiredness are common signs of illness in dogs, but they are rather vague — lots of different problems can make your dog appear lethargic and weak.

What should I do if my dog is lethargic?

If your dog is getting on in years they may steadily become more lethargic. This could be down to osteoarthritis or another age-related condition that’s causing pain or intolerance to exercise.

If your dog is younger but suddenly starts appearing weak, listless and lethargic it may signify a more serious problem. This is especially the case if it’s accompanied by not eating or drinking. In either case, you should contact your vet for advice or, if it’s out of hours and you feel it’s an emergency, your nearest Vets Now pet emergency clinic or 24/7 hospital.

A dog looking to the distance for Vets Now article on lethargic dogs
Lethargy, weakness and sudden tiredness are common signs of illness in dogs

Why is my dog lethargic?

There are several reasons that could be causing your dog to appear tired and listless. The most common causes of lethargy in dogs are:

  • Infection, including parvovirus, distemper, kennel cough and leptospirosis
  • Metabolic diseases, such as heart problems, liver problems, diabetes, and hypoglycaemia
  • Medications, such as newly prescribed drugs or a new flea or worm product
  • Anaemia, which is often caused by parasites such as a flea infection or intestinal parasite
  • Poisoning, from toxic foods, such as garlic and onions
  • Pain, trauma, diarrhoea, hypothyroidism, tumours

Is my puppy sick or just tired?

Puppies need a lot of rest. On average, they will sleep for between 15 and 20 hours a day and this is essential to their healthy development. But, during waking hours, puppies should be full of energy. If you have a puppy who is constantly tired and listless, you should contact your vet straight away as this is almost certainly a sign of an underlying problem. Lethargy is a symptom of a wide range of illnesses that can affect puppies, including parvovirus, pneumonia, anaemia, fever, congenital heart disease and malnutrition.

Treatment for lethargy in dogs

If you have a lethargic dog who is not himself, you should take him to your vet. It’s likely they will perform a thorough physical examination as well as ask questions about your dog’s recent behaviour and past health record. In most cases, diagnostics tests will be carried out such as blood, urine and faecal tests. It’s possible your vet will also perform x-rays, imaging scans and an electrocardiogram to check for heart problems.

Dog depression

Just like humans, dogs can suffer from mental health issues such as depression. Depression in dogs is usually sparked by a major change in their circumstances, such as the loss of their owner or of a companion animal, another pet, baby or partner moving into their home or, indeed, you and your dog moving into a new home. Persistent boredom can also lead to depression in dogs as can dermatological issues.

Signs of depression in dogs can include being less playful, interacting less with other dogs, lack of appetite, being less sociable and chewing or licking paws. Thankfully, as long as they’re given plenty of love, care and attention, most dogs will get over depression within a week or two.