What is lethargy in dogs and when is it an emergency?

Updated 20/12/24

Is your pup having a “meh” day, or could there be something more going on? Lethargy in dogs is more than just being a bit sleepy – let’s find out what could be causing your furry friend’s low energy levels, and what you need to do about it. 

Key takeaways

• Lethargy in dogs is usually accompanied by a general disinterest in normal activities.
• It may be a sign your furry friend has an underlying health issue.
• Take your dog to the vet if you have any concerns about their symptoms.

What is lethargy in dogs?

Here’s what lethargy in dogs can look like:

• Unusual fatigue (beyond feeling sleepy post-walk)
• Weakness and low energy levels
• Looking less alert or “zoned out”
• Trouble getting up and moving around
• Feeling stiff
• Reluctant or unable to leave their bed
• A lack of interest in food, playtime, or walks
  

Signs of lethargy in dogs can differ from pup to pup, but it’s usually characterized by a change in behavior and an overall disinterest in their day-to-day activities.

Normally, even the sleepiest pooch will spring to life at the smell of a tasty treat or the sound of the doorbell. If your dog is lethargic, those tail-wagging triggers might barely get a blink. And while a nap is usually enough to refresh a tired dog, waking up just as sluggish might be a sign there's more to their sleepiness than meets the eye.

So, what does lethargy look like in dogs? Pet parents are the best ones to judge whether their furry friend’s behavior is out of the ordinary or not, so keep an eye out for any unusual signs.

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Common causes of lethargy in dogs

Lethargy can be tied to all sorts of health conditions. It’s a non-specific symptom that can be seen in many disease processes. Sometimes a lethargic dog is just tuckered out from a busy day, but if it’s accompanied by other symptoms, there might be more going on.

Here are just some of the conditions that could be behind canine lethargy:

• Pain or injury
• Arthritis
• Nutritional deficiency
• Digestive issues
• Diabetes
• Anemia
• Hypothyroidism
• Viral or bacterial infections
• Internal parasites
• Liver, kidney or heart disease
• Cancer
• Neurological disorders
• Eye problems
• Medication side effects
• Mood changes or a mental health dip 
• Poisoning (from a toxic substance or insect)
  

Sadly, dogs often slow down significantly when they’re nearing the end of their life. You might notice your buddy has trouble getting up or loses interest in treats or meals – if this occurs, you must contact your vet for advice.

Lethargy in dogs: When to worry

Remember, dog lethargy is more than being simply pooped from a long walk – it’s also about being disengaged and disinterested in usual activities. If your pup can’t be tempted by their favorite snack or toy, or their lethargy is accompanied by any other worrying symptoms, take them to the vet immediately for a proper diagnosis. 

Other symptoms to watch out for include:

• Loss of appetite
• Vomiting or diarrhea
• Change in behavior
• Labored breathing or panting
• Pale gums
• Drooling
• Fever
  

On the other hand, if your furry friend perks up after a long nap, it’s unlikely to be cause for concern. If they still get excited for treats, belly rubs, or their favorite people, they may have just needed a bit of extra rest. Even so, a chat with the vet never hurts – they’ll know if it’s worth taking a closer look.

If you’re unsure whether your dog’s lethargy is serious, there’s no harm in speaking to the vet. They’ll want to know how long it’s been going on and if anything else seems “off”.They’ll also be able to judge whether your pup needs urgent care. They may tell you to monitor your pup for a little while if there is nothing immediately concerning, or they could ask you to come in so they can run diagnostic tests.

If in doubt, speak to the vet

Sometimes, a lethargic dog may have just overdone it after a busy day – other times, lethargy can be a symptom of something more serious. If your furry friend’s energy is lower than usual, taking them to the vet can provide peace of mind. And if you notice any concerning symptoms along with the lethargy, a trip to the emergency vet is in order.

Considerations for pet sitters

If a dog starts acting lethargic while you’re pet sitting, it’s important to keep a close eye on them. 

• Contact the vet if the pup seems unusually low on energy or disinterested in things.
• Keep the pet parents up to date about any changes in behavior. They might have additional insights or instructions for you based on their pup’s typical routine and health.
• Monitor the dog for additional symptoms like vomiting, loss of appetite, or labored breathing.
• Keep emergency contact info to hand, including a nearby emergency vet in case symptoms worsen. 

Meet our veterinary expert, Rebecca

This article has been checked by veterinarian Rebecca MacMillan, BVetMed MRCVS. Rebecca is a companion animal vet who has always had a passion for writing and client communication. Since her graduation from the Royal Veterinary college in 2009 she has gained a wealth of experience in first opinion small animal practice, in both clinical and managerial roles. She currently works in the South West and deals with a variety of routine and emergency appointments, but particularly enjoys medicine cases. Outside of work and writing, she enjoys spending time with her family, including her bouncy flat coated retriever George!