Cat low energy – when should I see a vet?

Updated 2026-09-30 · 1 sources

Based on: PDSA

Contact a vet today

This can have a serious cause – contact your vet today if any of the warning signs below apply, or if you are unsure. Lethargy can be caused by many different problems, some minor and some more serious.

When to contact a vet What to do now

Contact a vet if you see any of this

Low energy lasting more than 24 hours
Severe low energy

What you can do now

Contact your vet.
Note when it started, how often it happens and what else you see.
Take a photo or short video to show the vet.
Keep fresh water available.
Let your cat rest somewhere calm.

Don't

Do not give any human medicine.
Do not wait if it gets worse.

What it can mean

Lethargy can be caused by many different problems, some minor and some more serious.^[1] A lethargic cat may be quieter than usual or less interested in food, playing, hunting or going outside.^[1]

Other signs that can come with it

Quieter than usual
Less interested in food
Less interested in playing
Less interested in hunting
Less interested in going outside

Possible causes

Infections
Obesity
Pain
Heart disease
Anaemia (low red blood cell numbers)
Kidney disease
Liver disease
Hormone problems
Certain medicines
Poisons

What the experts say

“Overview. Does your cat seem lethargic (low in energy), quieter than usual, less interested in food, playing, hunting and going outside? Lethargy is a symptom that can be caused by many different problems, some minor and some more serious.”
— PDSA [1]

If your pet is struggling to breathe, has collapsed, is having a seizure or can't stand up: go to the nearest vet now.

Not sure how serious it is?

OkPaw asks a few quick questions about your pet and tells you in 30 seconds whether it can wait. Free on Google Play for Android.

OkPaw is on Android now – an iPhone version is on its way.

Common questions

What does lethargy mean in a cat?

Lethargy means low energy.^[1]

Can low energy in a cat be serious?

It can be caused by many different problems, some minor and some more serious.^[1]

When should I contact a vet?

Contact your vet if your cat has been lethargic for more than 24 hours, or book an urgent appointment if your cat is severely lethargic.^[1]

Sources

PDSA

How this page was made: written with the help of AI from the sources below, then checked claim by claim against those sources. Urgency levels follow OkPaw’s fixed safety rules. It is guidance, not a diagnosis. How we write our pages

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