Lethargy in Dogs: Causes and Treatments

A lethargic dog is sleeping more, disinterested in daily life, and less active than usual. Lethargy is a common sign that can have a wide range of causes. This article explores why dogs become lethargic, how we can determine what’s behind it, and what we can do about it.

What is Lethargy in Dogs?

Lethargy is much more than a dog who is lazy or prefers to snooze in front of the sofa rather than go on a hike. A dog who is lethargic is acting noticeably different from usual and lacking its normal energy. It won’t be keen to play or go for walks, and it may only want to sleep.

Common Causes of Lethargy

Lethargy is one of those vague symptoms that tells us something is wrong but doesn’t tell us much more. We often need to put on our detective hats to determine why the dog is off-form.

Illness and Infections

As the immune system fights off an infection, it zaps the dog's energy. The dog may have a fever and feel achy, meaning it has little to no interest in playtime or walks. It also feels tired and fatigued, preferring sleep to any other activity.

Toxin buildup from organ disease, lower oxygen levels from heart or lung disease, and nausea can all contribute to lethargy.

For dogs with swollen abdomens, we’d have to consider more serious causes, such as gastric dilation (in those with deep chests), cancer, or pyometra (in unspayed females).

Chronic Conditions

Several ongoing diseases, such as hypothyroidism or liver disease, can make a dog lethargic. Of course, these patients will have other symptoms, and the change in their energy level will have come on insidiously.

Pain or Injury

It makes sense that a dog who is sore or uncomfortable will be less inclined to jump up and run about. They’ll want to lie down and keep still to stay comfortable. As well as staying in their bed, you might notice stiffness, a limp, a tense abdomen, a hunched posture, or a desire to lick at one spot incessantly.

Emotional and Behavioral Factors

An excellent example of this would be a rescue dog who has been re-homed and is staying in their bed. They are dealing with high levels of anxiety and finding everyday life hard to cope with. For some, the over-stimulation and stress can lead to them ‘shutting down’ and just wanting to sleep as a form of coping.

Dietary Deficiencies or poor nutrition

Less commonly, dogs will be lethargic because something is lacking in their diet. If the diet is lacking in vitamins or minerals, this will have profound effects on the dog’s metabolism and activity levels.

Feeding a complete diet is the best way of preventing this, though deficiencies can still be seen if a dog has a heavy parasite burden or a malabsorption disorder.

Recognising the Signs of Lethargy in Dogs

It’s not always easy to classify a dog as being lethargic or not, as often they are sleepy but still active at times, or low energy but still willing to play with their ball if you roll it past them.

Physical Symptoms

You may find that your dog is uninterested in walks or playing and is off its food. It will be sleeping more than usual and less interactive.

Behavioral Changes

They may be slower when moving about, and less reactive to things like the doorbell or guests coming over. If you call them or ask them to do something, you may find they ignore you or do not obey commands they would usually be happy to comply with.

Diagnosis and When to Visit the Vet

Unexplained lethargy, especially if it persists for more than a day, is worth exploring. This is especially true in active and young dogs and if other signs, such as a limp, vomiting, or pale gums accompany it.

Physical Examination

Your vet will take your dog’s recent history from you and perform a nose-to-tail check. They will assess things like hydration levels, gum colour, heart rate, lung sounds, and temperature. They’ll also be paying attention to how your dog is acting.

However, remember that the adrenaline of a visit to the vet can often lead to a temporary improvement in lethargy.

Diagnostic Tests

Your vet may discuss running some tests, to determine why your dog is acting this way.

Depending on your dog’s age and breed, as well as the findings of the physical exam, this could include e.g. a blood test (biochemistry, heamatology, and electrolytes), a urine analysis, and perhaps some imaging like an abdominal scan. For those with diarrhoea or bloody stool, a stool analysis may be considered.

Underlying Conditions

As lethargy is a sign of an underlying problem, the vet is tasked with determining what the inciting condition is. Therapy would then be focused on this, and the lethargy should be resolved.

Treatment and Management for Lethargy in Dogs

Treatment will vary from one patient to another, as the causes of lethargy are so varied.

Veterinary Interventions

Depending on the underlying issue, your vet may issue medicines (such as antibiotics or pain relief), or supportive care such as IV fluids and assisted feeding. They may also discuss a prescribed diet and/or some supplements as your dog recovers.

Home Care

Your furry friend will need plenty of rest, nutritious foods and fresh water. As much as you can, keep the home calm and quiet, and they should have a predictable routine.

Monitor closely for any new signs, and follow up urgently with an emergency vet if they are deteriorating.

Monitoring Progress

Observe your pet’s energy levels, sleep, general behaviour, and eating habits. It can be helpful to keep a diary to monitor their improvement.

Preventing Lethargy in Dogs

You cannot always prevent lethargy, but you can do a few things to keep your dog in good health.

Balanced Diet and Proper Nutrition

Stick to a good quality dog food suitable for your dog’s life stage and activity levels. Try to ensure they are not filling up on other things, and treats and extras should make up no more than 10% of their daily calorie intake.

Regular Exercise and Mental Stimulation

Keep your dog engaged by providing them with a variety of activities, toys, and food puzzles. It is a good idea to rotate toys and develop new games and training activities.

Routine Vet Check-Ups

Regular check-ups are crucial for diagnosing medical issues early on and monitoring your dog’s weight and general condition.

Learn More About Lethargy in Dogs

If you’re concerned your dog is lethargic, you can contact us anytime to organise a vet check. Our vets can help determine why your dog has been acting this way and what action needs to be taken next.

FAQs

Why is my dog suddenly lethargic?

Lethargy can be caused by overexertion, lack of sleep, viral infection, or liver disease. It’s a vague symptom caused by many different things.

How do I know if my dog’s lethargy is severe?

The ongoing lethargy or other concerning signs (such as pale gums, abdominal swelling, weight loss, or enlarged lymph nodes) should be looked into.

Can stress or anxiety make my dog lethargic?

Certainly, yes. This is seen, for example, in dogs in kennels who are constantly on guard and barking. The day they come home, owners often find they sleep all day long.