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What to Know About Lethargic Dogs

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What to Know About Lethargic Dogs

Most dogs enjoy running and playing which is why when they are lethargic it can be a major concern. Lethargy in dogs can be a sign of their age, but also a variety of health problems, like an infection. If your dog is acting very tired and weak, you’ll want to check out this article. It will explain more behind why they might be acting the way they are and how you can help them.

What Does it Mean to Have a Lethargic Dog?

The definition of lethargic can vary although it mainly means being very sluggish, inactive, and drowsy. Lethargic dogs that fall into this definition should be taken to their veterinarian immediately.

My Healthy Dogs are Lethargic; When to Be Concerned?

dog lethargic

Sometimes healthy dogs just are a bit tired and lethargic. This is completely normal, but there is a time when it can be a concern. For instance, if your dog is lethargic for many days, acting strangely, or having health problems, it’s a good idea to start thinking about taking them to your vet.

How Long Do Dogs Typically Sleep?

The average time that adult dogs sleep per day is 12 to 14 hours. So, there’s nothing to be worried about if your dog sleeps this long. However, if they sleep for excessive hours over a longer course of time and have some of the symptoms mentioned below it could be a serious problem.

Why Is My Dog So Tired? Causes of Lethargy In Dogs & Other Symptoms

Lethargy dogs can be caused by a handful of things.

Below are some common reasons why your dog has no energy.

Their Age

Sometimes lethargy is caused by nothing more than the dog’s ageing process. As your pet ages, their body does as well. Because of this, older dogs might not feel much like playing or being active. While taking naps and being a little slower isn’t necessarily a concerning sign, it can be if they don’t do it at all or don’t feel like even getting up to eat or drink.


Infections are another common problem that often cause lethargy in dogs. Dogs can be infected by various infections, like kennel cough, heartworm disease, and parvovirus. Because these viruses are making their immune system work over time in order to try to eradicate the problem, it can take a toll on their health. This can eventually lead to them being very lethargic dog.


This medical condition is caused by low blood sugar amounts in the body. Because of this, it can make your dog feel very tired and weak. Sometimes it might even lead to seizures if not treated. Again with no energy from the nutrition, you will create a lethargic dog if this is left untreated.


Hypothyroidism is when the thyroid gland doesn’t work properly. This can lead to numerous problems, including hormonal imbalances and severe lethargy. If you suspect your tired dog might have this, it’s important to take them to your vet as soon as possible. If left untreated, it can lead to many serious health problems, some of which can be fatal. 

Food Poisoning

Another cause of a lethargic dog could be that they ate something bad. For instance, if they gobbled down food that is toxic to them, like garlic and chocolate, it could make your dog weak.

Urinary Tract Disorder

A urinary tract disorder, or UTI in dogs can cause bad bacteria to build up in your dog’s body. Because of this, it can cause them to feel very lethargic because their body is trying to fight off the bacteria, like E. coli. A problem with the urinary tract will create a tired dog, but can cause pain which can make it difficult for them to urinate. Your pet's health can be seriously affected by this as it can be fatal in the long term.

Nutritional Deficiencies

Sometimes a lethargic dog is suffering from nutritional deficiencies. If your dog is not receiving enough iron, Omega-3s, Vitamin A, and Vitamin D, it can make your dog lethargic and sickly. By not having enough nutrients, their body can feel very weak which can lead to not only lethargy, but a few health issues and serious illness as well.


Another reason for lethargy in dogs is if they are taking medications that make them feel fatigued. While there will usually be disclaimers warning you about this problem, some pet owners are often surprised to see their once lively dog turn lethargic after taking medications.

Extra Weight

If your dog is overweight, it can take a toll on their health. It can make it very difficult for them to move around and could cause labored breathing and painful joints. This could end up causing them to feel lethargic because it’s too difficult for them to move around.

Heart Problems

The heart helps to power the body. If your dog’s heart isn’t working well, it could make them feel lethargic because there isn’t enough blood being pumped. If this lethargy from heart problems isn’t fixed quickly, it could lead to very serious issues, like congestive heart failure.

Lethargic Dog Symptoms

Besides being excessively tired, there are a few other symptoms you can watch out for to determine if the lethargy in your dog is normal or not.

They Don’t Want to Play or Walk

If your dog doesn’t want to play or walk it could be due to lethargy. This can be a sign of them not feeling well as their body doesn’t have enough energy to move around. They might also feel other symptoms such as drowsy and dizzy which can cause them to not want to move.

They Aren’t Acting Themselves

Dogs that aren’t acting themselves can be a concerning sign. This could be caused by depression or of them being in pain and not knowing how to deal with it. Also, if you feel your buddy is suffering from dog depression you might want to make adjustments to stimulate their mental health.

My Dog is Lethargic and Won’t Eat

dog depression and decreased appetite

Another concerning sign of a weak dog is that they have a decreased appetite. A loss of appetite could be caused by stomach pain, inflammation in their body, or other similar problems. If your dog is not eating, you need to take them to your vet immediately. Otherwise, their body will become too lethargic and lose important vitamins and proper nutrients. This could end up causing them to rapidly lose weight which can be very damaging to their health.

They are Having Breathing Problems

Lethargy could also be a sign that your dog is having respiratory problems. This could include difficulty breathing, asthma, and even cancer. It could also be a sign of a collapsing trachea. Because of this, it’s extremely important to use the services of a vet as soon as possible if you find they are having these respiratory conditions. 

They Have Strange Shakes

Shaking paired with lethargy can be a sign of nerve issues or a neuromuscular disease. It could also be a sign of a fever and their body trying to cool them down. 

They are Confused


confused dog lethargic | Innovet Pet


Confusion can sometimes be caused by lethargy. If you try talking to your dog or give them commands and they don’t respond, it can be a problem. This is usually because they are severely drowsy due to their lethargy and unable to process what is going on.

My Dog Is Lethargic But Eating And Drinking

As mentioned above, sometimes dogs can be lethargic just due to age or they just want to rest for a little bit. Because of this, if your dog is lethargic but eating and drinking there isn’t much cause for concern. However, if this lasts for a few days or you see other worrying symptoms, it might be good to take them to the vet to have a checkup.

My Dog Is Lethargic: Lethargic Puppies

Lethargic puppies are a little more concerning than lethargic older dogs. Because their immunity is not fully developed, a lethargic puppy can be a sign of a virus or infection, like FeLV, hookworms, and parvovirus. Sometimes even ticks can cause your puppy to be lethargic because they drain their blood and could have diseases. Due to this, it’s very important to take any lethargic puppy to your vet immediately.

However, keep in mind that puppies also tend to sleep anywhere from 10 to 15 hours per day. This is very important to their development and is not a concerning thing. While they might sleep a lot, puppies are still very active and playful when they wake up. If you find your puppy has low energy levels and is tired all the time, that is a red flag you should be a bit worried and look into a physical examination from your veterinarian.

Ways To Treat A Lethargic Dog

There are plenty of ways you can treat a lethargic dog. Below are some of the most common methods to use and pay attention to.

Seek the Services of a Vet

One of the most important things to do if you find your dog is suspiciously lethargic is to take them immediately to your vet. They will be able to run tests and examine your pet to determine what the cause of their lethargy is. Some might also use X-rays or ECGs to help figure out what the issue might be. Once a diagnosis is made, your vet will then come up with a treatment plan and probably prescribe a medication to help them.

Add Vitamins and Supplements to Their Meals

Another way to help treat lethargy in dogs is to add vitamins and supplements to their meals. These will not only help to keep their body energetic but healthy as well.


Omega-3s are extremely important to keep in your dog’s diet as they are healthy fatty acids your dog’s body needs. They not only reduce inflammation in the body, but also work to stop yeast infections, heal allergies, and help with digestive problems. You can give your dog Omega-3s through fish oil or flaxseed supplements. These come in various forms, including in a liquid, which you need to measure out, or small treats.

Vitamin A

A low amount of Vitamin A (also known as beta-carotene) can cause your dog to have a weak immune system. It can also lead to their skin being very dry. You can feed your dog treats with Vitamin A mixed into them or through various food choices, like carrots, pumpkin, and sweet potatoes.

Vitamin D

While too much of Vitamin D in dogs can cause significant health problems, low amounts of it can also be just as unhealthy. Dogs need Vitamin D to help keep their bones strong and flexible. Otherwise, their bones might end up having too much calcium in them which can result in inflammation, lethargy, and bone pain. There are some Vitamin D supplements you can give your dog, and many dog foods include Vitamin D in them. However, some natural alternatives include salmon, sardines, and cheese.

Vitamin E

Vitamin E helps protect the Omega-3 fatty acids in the body, which work to keep your dog’s heart, muscles, and nerves healthy and functioning properly. One popular option to give your dog to ensure they have plenty of Vitamin E is peanut butter. Dogs not only tend to love the taste of it, but it’s very easy for them to consume. However, as with every type of vitamin and supplement, be careful to only give your dog a small amount of it. Too much Vitamin E can be harmful to your dog.

Try to Keep Them Active

For dogs whose lethargy might be caused by their weight, you can work to keep them active. While these should not be extreme exercises, normal activities like simple walks around the block or a quick game of fetch can be a big difference and very beneficial. You could also consider giving them toys which can help to keep them active both mentally and physically. By doing so, they will not only eventually start to lose weight, but be much more active and energetic.

Use Digestive Enzymes

Digestive enzymes can help to keep your dog healthy thanks to the beneficial bacteria it contains. Four of the most important enzymes for a dog to have are protease, amylase, lipase, and cellulase.


Protease is needed in order to help your dog’s body break down protein. It works to convert it into amino acids which can increase muscle growth, lower fatigue, and help with keeping the liver healthy.


Amylase is usually produced by dogs in their saliva, although sometimes it can not be produced if your dog has health issues. Amylase helps to keep the digestive tract functioning properly as well as their pancreas and small intestine.


This digestive enzyme is primarily found in the pancreas. While increased levels of it can be dangerous, it’s also a very important digestive enzyme to have as it keeps the pancreas working well. It helps to break down fats, starches, and oils.


Cellulase is often recommended by vets to help with the digestion of grains and plants. This aids your dog’s pancreas which is not designed to fully break down the particles of these items. In addition to improving digestion, cellulase also helps with maintaining healthy blood sugar levels and improve their immune system. 

These enzymes not only help with digestion, but your dog’s immune system as well. You can get digestive enzymes throughout supplement forms or even by just giving your pet a spoonful of plain yogurt or kefir.

Consider Weaning Them Off of Medications

Many medications often come with a side effect of lethargy. This is because of their chemical composition which can make your dog feel drowsy and tired. While a new drug might be absolutely crucial for your dog to have, sometimes certain medications can be eliminated. However, you should not determine this yourself. Rather, visit your vet and discuss your concerns with them. They will able to help guide you as to the medications that might not be necessary for your dog to keep taking.

Try to Cheer Them Up

Sometimes dogs can be lethargic due to depression which the most common causes are grief or boredom. Because of this, try various ways to help improve their mood. Many veterinarians recommend keeping your dog active with routine meal times, exercise, and cuddling. You can also give them some toys and treats they can enjoy to try to keep their mind off of whatever is troubling them. While you need to keep a close bond with your pet to help them, don’t overdo it. Sometimes doing too much can make the problem worse and could cause them to become irritated or snap at you.

You can also work to prevent stressful situations which might be a cause of their lethargy. This could range from them not handling loud noises well, like storms and fireworks, to not being able to cope with new houseguests. You can create a “safe space” for your dog to hide in which can help to reduce their stress, make them feel safe, and possibly help to reduce their causes of lethargy.

If your dog is acting lethargic, it can be a concerning sign, especially if they are usually active and playful. If you find that your dog is acting very tired and sickly, keep the information above in mind as it will help to guide you as to why your dog is acting like this and how they can be treated. Once treated, your dog's life can get back to living normally and enjoying the things they love to do.


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Approved by:

Dr. Ivana Vukasinovic

Doctor of Veterinary Medicine, University of Belgrade

Ivana Vukasinovic grew up in Serbia and attended the University of Belgrade where she received a degree in Veterinary medicine in 2012 and later completed surgical residency working mostly with livestock. Her first year of practice was split between busy small animal practice and emergency clinic, and after two more years of treating many different species of animals, she opened her own veterinary pharmacy where an interest in canine and feline nutrition emerged with an accent on fighting animal obesity. In her free time, she acts as a foster parent for stray animals before their adoption, likes to read SF books and making salted caramel cookies.


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The Innovet Team

Please do not ask for emergency or specific medical questions about your pets in the comments. Innovet Pet Products is unable to provide you with specific medical advice or counseling. A detailed physical exam, patient history, and an established veterinarian are required to provide specific medical advice. If you are worried that your pet requires emergency attention or if you have specific medical questions related to your pet’s current or chronic health conditions, please contact or visit your local/preferred veterinarian, an animal-specific poison control hotline, or your local emergency veterinary care center.

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