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Lethargic vs Tired Dog: How to Tell the Difference

The old saying goes let sleeping dogs lie, but can dogs ever sleep too much? Can sleeping be signs that something is wrong?

Written by: Sassafras Lowrey, MFA, CPDT-KA, CTDI

Last Updated on January 24, 2024 by Dogster Team

A sick or tired pug lying down on the floor.

Lethargic vs Tired Dog: How to Tell the Difference

The old saying goes let sleeping dogs lie, but can dogs ever sleep too much? Can sleeping be signs that something is wrong? While many dogs sleep a lot, a change in energy for your dog could be a sign that there is an underlying medical condition and may be a symptom of a larger issue. If your dog acts like he doesn’t have any energy, he might be lethargic, which is often a symptom of an underlying medical condition.

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What Is the Difference Between a Dog Who Sleeps a Lot and a Dog Who Is Lethargic?

Contrary to popular belief, you can’t figure out if a dog is lethargic just by looking at his sleep patterns. Dr. Kimberly Hammer, Internal Medicine specialist and Medical Director at NorthStar VETS, advises that “Dogs who are lethargic may sleep a lot, but they also tend to be mopey when they are awake.”

While dogs who are lethargic might be sleeping more, the important thing to observe is how your dog is acting when he is awake to determine if your dog is sleepy or if your dog might be lethargic. Registered Veterinary Technician and Embrace Pet Insurance Claims Manager Rachel Hinder explains that “Lethargy can often be witnessed when a dog is awake. Lethargic dogs appear to have very low energy, but it doesn’t always mean that they are sleeping more than normal.”

Symptoms of Lethargic Dogs?

Increased sleep may be a sign your dog is lethargic, but our experts explain a more telling way to determine if your dog is lethargic — look at your dog’s behavior is like when they are awake. Dogs who are lethargic may have a decreased appetite and show less enthusiasm for treats and toys.

Dr. Hammer explained that a dog who has lethargic may be less interested in daily activities such as walks or playing.” In addition to a decreased interest in normal activities, a dog who is lethargic might withdraw from the family. “He or she may also be less interested in his or her surroundings such as other pets or family members.”

To determine if your dog is lethargic, look at your dog’s whole day, how much he is sleeping as well as if his general interest in play and activity changes.

west highland terrier dog lying on the carpet
Image Credit: Bogdanovich_Alexander, Shutterstock

Issues Associated With Lethargic Dogs:

Lethargy in dogs can be the result of a variety of conditions. Common causes of lethargy differ based on the age of dogs. Rachel says that with young dogs’ lethargy is often caused by: “infectious disease, such as: parvovirus, parasites, kennel cough, pneumonia, malnutrition, hypoglycemia (low blood sugar), intoxication and congenital abnormalities, such as a portosystemic shunt.”

With older dogs Hinder says lethargy might more likely be a sign of “cancer, arthritis, heart/liver/kidney disease, tick-borne illnesses and hypothyroidism.”

How to Help a Lethargic Dog:

If your dog becomes lethargic, keep him as comfortable as possible. Make sure that your lethargic dog rests in areas of your home that are climate controlled — warm in the winter, cool in the summer, and dry. Rachel says that sometimes lethargic dogs have a change in appetite. She reminds guardians to make sure the dog has access to water and to maintain regular meal schedules.

“If the dog stopped eating his/her normal food, try something that might be more enticing (ground turkey and rice, for example),” she says. However, she also cautions that if your dog refuses to eat you shouldn’t ever force feed your dog, and that doing so can result in more serious medical complications.

When Should You Consult a Vet?

Because lethargy is a symptom of so many different diseases and conditions, both Rachel and Dr. Hammer advise that lethargic dogs should be seen by your family vet to develop an appropriate treatment plan.

While all dogs might have a quiet day here and there, Rachel gave this guidance for determining if it’s time to schedule a vet appointment: “If a pet becomes acutely and dramatically lethargic, you should seek veterinary consult right away.” Additionally, “If a pet becomes lethargic and it persists, you should take him to the vet; there are many causes that should be treated sooner rather than later” she explains.

It can be unnerving when your dog’s behavior or interest in things suddenly changes, or your dog becomes withdrawn or sleeping more. Unfortunately, lethargy in dogs is a symptom of so many conditions you really need a veterinarian to determine what is going on with your dog’s health and how to help them feel better regain normal activity levels

Learn more about common health issues in dogs on

Featured Image Credit: Monica Click | iStock / Getty Images Plus

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