Why Is My Cat Lethargic?

Lethargy means low energy. It can point to anything from a simple abscess to a serious illness, so know when to call your vet.

Quick Answer

Lethargy means a cat is low in energy, quieter than usual and less interested in food, play, hunting and going outside.
Lethargy has many causes, some minor and some serious, so only a vet can find out which one applies to your cat.
Cats often sleep 12 to 16 hours a day or more, but sleeping more than usual can be a sign that something is wrong.
Contact your vet if your cat has been lethargic for more than 24 hours, and book an urgent appointment if it seems severely lethargic.
Collapse, breathing trouble, white or blue gums, or possible poisoning is an emergency.

Why is my cat lethargic? Lethargy means your cat is low in energy. It may be quieter than usual and less interested in food, playing, hunting and going outside.

Lethargy is a symptom, not a diagnosis. PDSA says there are too many possible causes to list them all. Cats are also experts at hiding illness, so the signs can be very subtle.

Fluffy grey cat with folded ears resting its head on a dark sofa – resting is normal, but is your cat lethargic for more than a day? Call your vet

Is my cat lethargic or just sleepy?

Cats save energy for hunting, so they often sleep for 12 to 16 hours a day or more. However, if your cat is sleeping more than usual, it could be a sign that something is wrong.

Your cat's normal behaviour is the best yardstick, so a change is the clue. Cats Protection lists these general signs that a cat is unwell:

Hiding more
Drinking more or less than usual
Being off their food
Sleeping more than usual
Sudden weight loss
A change in grooming habits

Why is my cat lethargic? Possible causes

No source ranks these conditions, so the order below says nothing about how likely each one is. Each is listed with its other typical signs, to help you spot a pattern.

Infection and cat bites

An abscess can take two to three days to appear. Before then, a bitten cat may be lethargic, eat less, have a high temperature or limp. Blue Cross says that after a fight you may see no wound at all. See What Should I Do If My Cat Has an Abscess?

Cat flu

Signs include sneezing, discharge from the nose and eyes, red blinking eyes, lethargy, loss of appetite and a high temperature. Kittens, unvaccinated, elderly and stressed cats are at more risk, and it can occasionally be life-threatening. Our guide Why Is My Cat Sneezing? has more.

Fluffy orange and white cat lying on its side on a wooden floor – if you find your cat lethargic, tell your vet about any other changes

Pain and arthritis

A lack of energy, or a listless, hiding cat that eats less, can be a sign of pain. PDSA lists lethargy, resting more and playing less as signs of arthritis, and notes that cats hide pain. Blue Cross advises contacting your vet immediately if you think your cat may be in pain, and never treating it at home with human painkillers. See How Can I Tell If My Cat Is in Pain? and How Do I Know If My Cat Has Arthritis?

Kidney disease

PDSA lists drinking more, peeing more, eating less, weight loss, vomiting and low energy. Early disease may show no signs. See How Do I Know If My Cat Has Kidney Disease?

Diabetes

Signs can include drinking more, losing weight and sleeping more than normal. A serious complication called diabetic ketoacidosis can cause reduced appetite, weakness, low energy, vomiting and collapse. See How Do I Know If My Cat Has Diabetes?

Overactive thyroid and high blood pressure

Most cats with an overactive thyroid are hungry and restless. However, some are weak, tired and eat less instead. High blood pressure often has no signs until it is advanced. Where signs appear, they can include depression, tiredness, becoming withdrawn, bumping into objects and eye changes. See What Are the Signs of an Overactive Thyroid in Cats?

Pancreatitis and tummy upsets

Signs include eating less or refusing food, vomiting, tiredness and diarrhoea. Because cats hide pain, the only signs may be interacting less, sleeping more, resting in different places and grooming less.

If a vomiting cat is also lethargic, or has diarrhoea or pale gums, don't delay contacting your vet. See Why Is My Cat Vomiting?

Poisoning

Poisoning signs include drooling, vomiting, diarrhoea, twitching, wobbliness, breathing difficulty, collapse and changes in drinking, peeing or appetite. Lily poisoning can cause lethargy or vomiting within minutes of a cat eating any part of the plant. Read Are Lilies Poisonous to Cats?

Onion and garlic poisoning can cause tummy upsets first, then weakness, lethargy and pale or yellow gums within days. Painkillers meant for people can also be fatal to cats.

Kittens and older cats

Contact a vet if a kitten is lethargic, not acting normally or not wanting to play. Kittens can swallow human medicine, objects or toxins, and even small amounts of human medicine can be fatal to them.

Older cats can have several conditions that list tiredness as a sign, including kidney disease, an overactive thyroid, high blood pressure and arthritis. International Cat Care recommends regular blood pressure checks for cats over seven. In young or elderly cats, tummy upsets can be very dangerous because of dehydration.

What to note at home

If you find your cat lethargic, tell your vet about any other changes you have seen, such as eating less or drinking more. These notes help:

How long your cat has been lethargic
Appetite, drinking, vomiting and diarrhoea
Sudden weight loss or grooming changes
Whether your cat may have been in a fight or eaten something it should not

Keep a sick cat comfortable and warm, and indoors with a litter tray so it does not wander off. Do not force a cat to eat, and never give human medicines, including painkillers. Handling a very unwell cat can add stress, so follow your vet's advice.

Emergency: Contact a Vet Immediately If…

Your cat has collapsed, is not responding, or is not breathing.
Your cat is struggling to breathe, panting or breathing with its mouth open.
Your cat's gums look very pale, white or blue.
Your cat is very painful, cannot move, is weak, struggles to get up or has balance problems.
Your cat's belly suddenly swells, or it cannot pass urine, especially a male cat.
Your cat may have eaten something poisonous, such as lilies, onion, garlic, antifreeze or a human painkiller.
A diabetic cat is vomiting, eating less or not eating, weak, wobbly, twitching or collapsed.

Call your vet, or the nearest out-of-hours emergency vet if yours is closed, straight away. If poison is possible, take the packaging or a photo of the plant, and do not try to make your cat vomit at home.

When to Contact Your Vet

If your cat has been lethargic for more than 24 hours.
Urgently, if your cat seems severely lethargic. Book an urgent appointment.
If lethargy comes with hiding, sleeping more, going off food, drinking more or less, sudden weight loss or grooming changes.
If your cat is vomiting and also lethargic, has diarrhoea or pale gums, has blood in the vomit or seems to be in pain.
If a kitten is lethargic.

Cats hide illness well. If you think something is wrong, see your vet straight away rather than waiting.

How vets find the cause

Your vet will examine your cat and ask about any other signs. The tests depend on what they suspect. Kidney disease and diabetes are diagnosed with blood and urine tests. An overactive thyroid is confirmed with a blood test, and blood pressure may be checked.

Pancreatitis is diagnosed from signs, an examination and blood tests, and sometimes an ultrasound. Mild cases can be hard to diagnose, so treatment may start on suspicion.

Treatment depends on the cause. Severe illness, such as diabetic ketoacidosis, pancreatitis or poisoning, may need a drip and hospital care. The outlook depends on the cause too. Most cats recover from cat flu, and most recover completely from onion or garlic poisoning with treatment.

Some problems can be prevented. Vaccination protects against cat flu, parvovirus and feline leukaemia virus, and neutering reduces fights and bite injuries. A healthy weight helps prevent diabetes and arthritis. Keep poisons and lilies out of the home.

How Pet Med Direct Can Help

Your vet needs to find the cause of lethargy before any treatment starts. If your vet prescribes medicine for your cat, our guides to how pet prescriptions work and repeat pet prescriptions explain how we can help.

If your vet recommends a particular food, you can browse our cat food range, including veterinary diets.

Some pet medicines require a valid veterinary prescription. Pet Med Direct can only supply prescription medicines after the prescription has been checked. Always follow your vet's advice and the directions on the medicine label.

Frequently Asked Questions

How much do cats sleep?

Many cats sleep 12 to 16 hours a day or more. However, if your cat is sleeping more than usual, it could be a sign that something is wrong.

Is my cat lethargic if it is sleeping more than usual?

It may be. Sleeping more than usual can be a sign of illness, including diabetes. Contact your vet if the change lasts more than 24 hours.

Why is my cat lethargic and not eating?

Loss of appetite can come from kidney disease, cat flu, diabetes, fever, an overactive thyroid, pancreatitis, dental problems, pain, internal obstructions or stress. Going without food for 24 hours or more can seriously affect an adult cat, so call your vet. See Why Is My Cat Not Eating?

Is lethargy always serious?

No. Causes range from a simple cat-bite abscess to kidney disease, diabetes or poisoning. Even so, don't assume it will pass, because only a vet can tell which applies.

How long should I wait before calling the vet?

Contact your vet if your cat has been lethargic for more than 24 hours. Book an urgent appointment if it seems severely lethargic. Collapse or breathing trouble needs a vet immediately.

What if my kitten is lethargic?

Contact a vet. Vets Now lists a lethargic kitten, or one that is not acting normally or not wanting to play, as a reason to call.

What can I do at home for a lethargic cat?

Keep your cat comfortable and warm, indoors with a litter tray. Note any other changes and follow your vet's instructions. Never give human medicines.

Related Cat Health Guides

Sources and Further Reading

This article was researched from the sources listed above. It is general information for cat owners and is not a substitute for advice from your own vet.

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This article is for informational purposes only and does not constitute veterinary advice.
If you are concerned about your cat’s health, please consult a qualified veterinarian.