Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Lethargy in Cats: Symptoms, Causes & Treatments (Vet Answer)

Share

cat sleeping

Cats are well known for being stoic. They are also a predator-prey species. This means that, as much as they enjoy hunting mice, they are also wary of being preyed on themselves. This has led to a great ability to hide pain and illness, even from their pet parents.

So, while it is often quite obvious when dogs are unwell, cat parents have to be more savvy. Signs of pain or illness in cats are often very subtle.

divider cat faces oct 2024

What Is Lethargy in Cats?

Lethargy is a symptom rather than a disease. Lethargy is defined in the dictionary as “a lack of energy and enthusiasm.” In medical terms, lethargy is a state of inactivity or sleepiness brought on by illness, pain, or disease. Cats with lethargy may be quieter than usual or sleep more than normal, among other signs. There are many potential causes of lethargy in cats.

tired cat
Image by: thabisfotowelt, Pixabay

What Are the Signs of Lethargy in Cats?

Lethargy itself is a sign of an underlying problem.

If your cat is lethargic, you may notice:
  • Reduction in their activity
  • Sleeping more than usual
  • Loss of interest in their surroundings
  • Sluggishness

Since lethargy is a sign of an underlying problem, rather than a disease itself, it is often accompanied by other symptoms.

There are a great number of other symptoms which may accompany lethargy in cats. It is commonly found alongside:
  • Reduction in, or lack of, appetite
  • Changes in behavior (such as being less affectionate than usual, or more aggressive)
  • Weight loss
  • Fever
  • Vomiting and/or diarrhea
  • Pain
  • Coat changes (such as a dry, unkempt coat)
  • Jaundice (noticeable as yellow gums and eyes)
  • Increased thirst and urination
  • Changes in breathing

If you think your cat is lethargic it’s a good idea to try to determine if any of these other signs are present, which could help a vet to determine the problem.

divider cat faces oct 2024

What Causes a Lethargic Cat?

Lethargy in cats is quite a vague sign, with many potential causes, some more serious than others. Here are some of the most common causes of lethargy in our feline friends.

1. Obesity

There are some relatively simple causes of lethargy in cats, such as obesity or lack of fitness. However, it is important to note that if your cat is overweight but normally pretty active, a sudden decrease in activity is not likely to be caused by their weight.

Any sudden change in activity levels or behavior needs to be investigated by a veterinarian. If a veterinarian suspects that your pet is less active due to weight gain, it is time for a diet! Obesity is a growing problem in cats and can lead to a multitude of health conditions.


2. Fur Balls

young cat sitting on wooden table with hairball_RJ22_shutterstock
Image by: RJ22, Shutterstock

Another common cause is fur balls. Long-haired cats are especially prone. Fur balls can be pretty uncomfortable, causing your cat to feel groggy. This lethargy is usually short-lived, lasting only until your cat manages to bring up the offending fur. Sometimes, cats need a little help to pass fur balls—a veterinary clinic can advise you of the best options for your cat.


3. Stress, Anxiety & Depression

Stress or depression can also cause lethargy. You may have had builders in, a new baby, or a house move. You may have introduced a new animal to the house, or your new neighbors have a cat who is a bully. All these types of events can cause stress in cats, and this can make them hide away and feel lethargic.

However, cat emotions are not to be compared with human emotions. If you are worried that your cat is stressed or depressed, you should always contact a veterinary clinic for advice. There may well be an underlying cause that needs addressing.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money


4. Medications & Sedation

Lethargy can also be seen as a side effect of some medications. It is particularly common in kittens, following their first vaccination. If the vaccination is the cause of the lethargy, then they may be drowsy for 24–48 hours. However, they should still want to eat, drink, and toilet. If they don’t, contact a veterinary clinic for advice. If your cat has had a sedation or anesthetic, such as for surgery, then they may be lethargic until the drugs wear off.


5. Anemia

Anemia is a lack of red blood cells, which carry oxygen around the body. Any illness involving anemia can cause lethargy as cats struggle to get the oxygen they need.

Cats can become anemic from many conditions, including:
  • Blood loss (such as trauma or a bleeding tumor)
  • IMHA (Immune Mediated Hemolytic Anemia, where a cat’s immune system destroys its own red blood cells)
  • FeLV (Feline Leukemia Virus) or FIV (Feline Immunodeficiency Virus)
  • Feline Infectious Anemia (caused by a blood parasite, mycoplasma haemofelis)
  • Toxins/poisoning (such as eating rat poison)
  • Chronic diseases
  • Chronic kidney disease
  • Cancer

6. Parasites

Some parasites in cats can cause lethargy, especially heartworm. It is also possible for a cat to become anemic from a very heavy flea or worm burden. This is especially true in young kittens.

giardia parasites
Image by: Kateryna Kon, Shutterstock

7. Pain

Pain is a common cause of lethargy in cats. We don’t always know when our cats have been injured, especially with outdoor cats. This could be pain from a wound (which can be surprisingly hard to find in cats), a muscular injury, or any trauma.

In older cats, arthritis is a common source of pain, and therefore lethargy. Some illnesses, such as pancreatitis (inflammation of the pancreas), are very painful.

Urine infections can be very painful too. Sometimes cats can get a blocked bladder, where a urinary stone blocks the tube carrying urine from the bladder. This means the bladder keeps filling and becomes very distended. This is an extremely painful and potentially life-threatening condition.


8. Fever

Fever and lethargy in cats are a common pair. Cat bite abscesses are one of the most common causes of fever in cats. They can form when a fight injury gets infected with bacteria. Many infections can cause a fever, as can pain and inflammation in the body. Some auto-immune diseases can also cause a cat’s temperature to spike.

sick cat
Image by: Flickr

9. Gastroenteritis & Gut Conditions

Any condition affecting the gut can cause cats to feel pretty rotten, likely from a combination of nausea and discomfort. This means that lethargy and sickness or diarrhea are frequently seen together.

A foreign body lodged in the back of the throat, stomach, or intestines is particularly painful and would usually cause marked lethargy. Blades of grass lodged in the throat and pieces of string stuck in the intestine are common ones in cats.

divider cat faces oct 2024

Other Causes of Lethargy in Cats

Regardless of temperature, any infection can cause lethargy. Cat flu and urinary tract infections are common ones. Urinary tract infections can be particularly painful too. Endocrine (hormone-related) disorders can cause a cat to become lethargic. Common examples in cats include hyperthyroidism and diabetes mellitus.

Other conditions that can cause lethargy include heart or lung disease, poisoning, cancer, and kidney or liver disease.

When Is Lethargy in Cats an Emergency?

With some conditions, your cat may feel rotten for a couple of days before turning a corner and feeling better on their own. An example could be a sickness bug or a bout of diarrhea. Other times your cat may need veterinary treatment, such as a cat bite abscess. Then there are some causes of lethargy that are a medical emergency, and potentially life-threatening. So, how do you tell the difference?

You should call a veterinary clinic for advice if:
  • Your cat has been lethargic for more than 24 hours
  • Your cat is lethargic and not eating or drinking
  • You notice any other symptoms as well as lethargy
If your cat has any of the following signs alongside lethargy, you should treat it as an emergency and call a veterinary clinic straight away:
  • Pale gums
  • Straining to urinate and not passing much or anything
  • Unresponsive or floppy
  • Fast or labored breathing
  • Any neurological symptoms, such as twitching or seizures
  • Vocalizing
  • Unable to stand or walk.

These are signs that the lethargy is a symptom of something serious that needs immediate veterinary treatment.

sleepy cat
Image by: rsteve254, Pixabay

divider cat faces oct 2024

How Is Lethargy in Cats Diagnosed?

A veterinarian will want to discover the cause of your cat’s lethargy. As you can see, there are many potential causes of lethargy in cats, so this can be time-consuming.

The veterinarian may:
  • Take a detailed history. This may give some clues as to the cause.
  • Perform a clinical exam. Again, this may narrow down the possibilities and would detect some potential causes such as pain or fever.
  • Perform urine tests, looking for water infections and diabetes.
  • Run tests on the feces, which can look for parasites and signs of bleeding into the guts.
  • Perform blood work. Blood work can look for many conditions; including anemia, FeLV, FIV, signs of infection, kidney disease, liver disease, diabetes mellitus, and hyperthyroidism.
  • Perform imaging, such as ultrasound and/or x-rays. These can be used to investigate many conditions; such as assessing the organs, and looking for tumors and bladder stones.

A vet may not need to do all of these tests, and the results of one test might indicate which tests can be skipped. However, because lethargy can be caused by so many things it can take a while to find the cause.

The vet should keep you appraised of which tests they need to do, and the results. If costs are an issue, try to bring this up with a vet as soon as possible so they can prioritize your pet’s tests.

How Is Lethargy in Cats Treated?

Treatment for lethargy in cats will depend on the cause. Some causes of lethargy will resolve themselves. Others should resolve with some simple treatment. Some conditions, however, require hospitalization. Surgery could be indicated, for example for some tumors or for a blocked bladder. Sadly, some cases cannot be cured.

Treatment for lethargy in cats could involve:
  • Pain relief
  • Antibiotics, for bacterial infections
  • Antiviral medication
  • Fluids through a drip
  • Dewormer
  • Medication tailored to the underlying condition, such as insulin for diabetes or hyperthyroid medication.

The vet will talk you through the necessary treatments. Sometimes, treatment will be on a trial basis to see if your pet responds, especially if the tests haven’t been conclusive as to the cause of the lethargy.

sleepy cat
Image by: Josephchae, Pixabay

What Is the Prognosis for Lethargy in Cats?

Lethargy in cats carries a wide-ranging prognosis; from an excellent chance of recovery to potentially fatal. This will depend on several factors, including the underlying cause of the lethargy, your cat’s overall health, and your cat’s age.

divider cat faces oct 2024

Conclusion

We all know that cats love to sleep! Just as in humans, some cats sleep more than others. It is important to be aware of your cat’s normal sleeping patterns, so that you can tell when their activity levels change.

Cats are stoic creatures, so unfortunately are often quite ill by the time they allow any signs to show. We need to keep this in mind when our feline friends are poorly since it means that we should take all symptoms seriously.

Lethargy is a broad symptom, with many possible causes and outcomes. If you have any concerns about your cat being lethargic, call a veterinary clinic for advice.


Featured Image Credit: eledhwen22, Pixabay

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

10 Facts About Cats’ Eyes: Vet Verified

We sometimes wonder if our cats see the world the same way we do. Are cats’ eyes similar to humans? Do they work...

Can Cats Eat Scrambled Eggs? Vet-Verified Nutrition Facts & Info

There’s no better breakfast than some nicely cooked scrambled eggs and a couple of slices of toast. It’s simple, delicious, and nutritious. So,...

Catster Photo Contest: Cats of the Week Winners (January 15, 2026)

Every week our team gets the privilege of sorting through our readers photos to choose what cats will win this weeks contest! See...

10 Ways to Monitor Your Cat’s Health at Home: Vet Verified

Thanks to their instincts for self-preservation, cats are masters at hiding signs of illness or injuries. If you want to catch medical problems...

More related

Is Feline Heart Disease (Saddle Thrombus) Hereditary? Our Vet Explains

Heart disease in cats is worryingly common in cats, with more than 15% affected worldwide. That’s an alarming 8.8 million cats in the...

14 Common Smells That Cats Hate (Vet-Verified!)

A cat’s amazing sense of smell is 14 times more powerful than ours, enabling them to detect even faint aromas most humans would...

10 Best Cat Strollers in 2026 – Reviews & Top Picks

Your cat would probably love to get out and explore. If you don’t want to fiddle with leash training or you just want...

How to Teach a Cat to Fetch: 8 Vet-Reviewed Steps

Fetch isn’t just for dogs—some cats love it too! While teaching a cat to fetch might take some work, once your cat gets...

Keep reading

How Do Cats Carry Their Kittens? & Why It Doesn’t Hurt Them (Vet-Verified Info)

If your cat has recently had kittens, you’ve probably seen her moving the kittens around by the scruff of their necks. Many pet parents worry that this hurts the kitten and that the mother cat does it as a form...

Mother cat running with newborn kitten in her mouth

Pet Poison Prevention Week: When It Is & Vet Approved Safety Tips

National Animal Poison Prevention Week (NAPPW) is an annual event that occurs during the third full week in March, and in 2024, it runs from March 17 to 23. The event is designed to educate pet owners on the substances...

cat with pill bottle

Don’t Panic Yet: What Happens When Cats Eat Silica Gel Packs

If your cat just chewed on a “DO NOT EAT” packet, take a breath. This is one of the most common pet-parent panics, and it happens because cats insist on investigating anything crinkly, tiny, or mildly forbidden. Silica gel may...

silica gel

How Can Cats Survive High Falls? Vet-Approved Science & Info

Cats have been wowing humans with their ability to handle high falls with relative ease. Cats have survived falls from great heights, although they don’t always come out unscathed from such incidents. However, the fact that they’ve survived is considered...

side view of a blue tabby white maine coon cat jumping down from birch tree in the back yard

Is Aglaonema Toxic to Cats? Vet-Verified Houseplant Advice

House plants are a fantastic way to give your home some life, so much so that many people have taken up the role of plant parents, adorning their space with greenery. Aglaonema commutatum, also known as the Chinese evergreen plant,...

Catster_Is Aglaonema Toxic to Cats

Are Neanthe Bella Palms Poisonous to Cats? The Facts & FAQ

Many people adore having house plants because they improve the appearance of the environment and can help clean the air in the home. Unfortunately, our precious cats can also greatly limit the plants most people can keep. This is because...

Catster_Are Neanthe Bella Palms Poisonous to Cats

Why Is My Cat Bobbing His Head? 6 Vet-Verified Reasons for This Behavior

Head bobbing in cats can occur for a variety of reasons, some simple and others more serious. In many cases, your cat’s head bobbing may simply be the symptom of a benign, temporary anomaly, like a stressful situation or overheating....

woman hands pet and massage on the head of gray and white adorable cat

How to Tell If a Nursing Cat Is Pregnant Again? 7 Vet Reviewed Signs to Look For

Felines are extremely fertile animals, with females able to experience heats every 2–3 weeks during the breeding season1. That adds up to multiple opportunities for your cat to get pregnant! What if your cat just had kittens, though; surely, she...

pregnant cat on the ground

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.