Lethargy in Cats – Causes, Treatment and Recovery

Picture of a sleeping cat

It can be quite difficult to tell whether your feline companion is lethargic or if she’s sleeping a little more than usual. If you are out of the house for 10 or more hours a day, you might not be aware of your cat’s sleeping habits, so you might accidentally think that something is wrong when in fact, your pet’s perfectly healthy.

In today’s post, we’re looking at what lethargy in cats means, its symptoms, what it can be caused by, and how it can be diagnosed and treated.

What Is Lethargy in Cats?

First of all, lethargy is a clinical sign, not a disease per se. It needs to be caused by something, whether a pathogen that causes an infectious disease or a chronic health issue that eventually affects an organ or system.

In general, cats that are lethargic have lower energy, don’t engage in the same activities that they normally love, and they tend to sleep more in an attempt to heal themselves.

Lethargy can often go unnoticed. What you should know is that this clinical sign is rarely the only one that affects cats. It’s usually associated with others, such as:

Cats usually sleep up to 16 hours in a day. As previously mentioned, if you don’t tend to spend a lot of time with your feline buddy, you might be surprised at how much a cat can sleep.

If a cat sleeps more during the day, she will be a bit more active in the evening or during the night. That means that she should want to play with you, cuddle, or investigate her living environment. If these normal behaviors don’t occur, and she also doesn’t seem to be interested in her favorite food or treats, something is going on, and you should take her for a checkup at the vet clinic.

What Can Lethargy Be Caused By?

In our feline friends, lethargy can be caused by a very wide range of health problems, but also stress and the side effects of different medications. Here are some less concerning causes:

  • Obesity or being overfed
  • Stress / depression / the lack of regular playtime
  • Changes in her living environment
  • Lack of exercise

However, lethargy can also be caused by serious medical conditions, such as the following:

  • Kidney and liver disease
  • Diabetes
  • Infections with contagious cat viruses (FeLV and FIV)
  • Anemia
  • Bacterial infections
  • Severe parasite infections
  • Arthritis (more common in geriatric cats)
  • Most types of cancer
  • Hypothyroidism
  • Gastrointestinal health problems
  • Poisoning
  • Neurologic disease

How Is Lethargy Diagnosed?

If you feel that your cat is lethargic, and she’s showing some of the other symptoms that are commonly associated with this health issue, you should take your pet to the vet as soon as possible.

Once at the clinic, the veterinarian will recommend a number of tests that can reveal what might be wrong. These range from a complete blood count (CBC) to biochemistry, an ultrasound, an X-ray, or anything else that might be necessary in order for the disease to be diagnosed.

In the absence of a clear and correct diagnosis, the vet can only prescribe some medications that can improve your cat’s symptoms. So even if you might feel that the tests are many and they are pricey, they are all useful in some way or the other.

If your cat drinks a lot of water and ‘goes to the bathroom’ unusually often, the vet might suspect diabetes, for instance, and will perform a specific test (to determine your cat’s blood sugar either with a blood test or using a urine sample).

If a parasitic infestation is suspected to be at the root of the problem, the vet will ask you to bring a fecal sample to the vet clinic. If one of the infectious viral diseases that cats can suffer from is suspected, your vet can perform a quick blood test.

As you can see, there are many medical investigations that could be recommended depending on your cat’s symptomatology.


The therapy that your feline companion can be prescribed also depends on what has caused the symptoms, including lethargy. For example, if your cat suffers from a bacterial infection, the vet will recommend an antibiogram, and the infection will be treated with antibiotics.

Cancer can be treated using surgery, chemotherapy, or radiation therapy, and you will choose the right one depending on the progression of the disease, what your vet recommends, and your cat’s health status (and ability to withstand the treatment).

Viral infections can be treated using an antiviral medication, parasitic infections can be treated with dewormers, and various behavioral problems can be treated with antidepressants, for instance.

If your cat has diabetes, she will be prescribed a different and healthier diet and maybe insulin (depending on her blood sugar).

Prognosis and Recovery

It’s difficult to tell whether your cat can become full of energy quickly or if it might take a longer time, and that’s because your cat could be suffering from a mild illness or something more serious.

The important thing to keep in mind is that the sooner your cat gets veterinary care, the better it is for her.

It’s also essential to remain optimistic, especially if you know that you take good care of your feline companion. If you take her to checkups at the vet clinic once or twice a year, it’s a good chance that the issue she’s suffering from can be diagnosed and treated before it becomes more severe.



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