Cats sleep between twelve and sixteen hours a day, and older cats and kittens sleep more than that. Sleeping a great deal is not, on its own, a sign of anything.

What matters is the difference between a cat that is resting and a cat that has withdrawn.

Normal sleep

A cat that sleeps a lot but wakes readily, stretches, greets you, eats with interest, grooms itself and plays when invited is a normal cat. Cats are crepuscular: most active at dawn and dusk, and asleep through much of the middle of the day and night.

Sleep also increases in cold weather, after a change of season, and in cats that have nothing much to do.

Sleep that is really withdrawal

The concerning pattern looks different. The cat sleeps in unusual places, often somewhere dark or enclosed and away from the family. It is slow to wake and does not greet you. It has stopped grooming, so the coat looks unkempt. It sleeps hunched with its paws tucked under and its head low, rather than stretched out or curled loosely.

Cats hide when they feel unwell. A cat that has moved from the sofa to the back of a wardrobe is telling you something.

What to check

Is it eating and drinking the same amount?
Is it grooming? An unkempt coat in a previously tidy cat is a real sign.
Is it using the litter tray normally?
Has it lost weight? Run your hands along the spine and ribs.
Does it react when you touch it in a particular place?
Is the breathing rate at rest under 30 per minute?

What causes genuine lethargy

Almost any illness. The most common in practice are kidney disease, anaemia, infection, pain from arthritis or dental disease, hyperthyroidism, diabetes, heart disease and poisoning.

In older cats, arthritis is the most frequently missed. It does not cause limping in cats; it causes a cat that has stopped jumping, stopped playing and started sleeping more, which owners reasonably read as simply getting old.

Boredom

In indoor only cats, excessive sleeping is often just an absence of anything else to do. Two short play sessions a day, food puzzles, window perches and vertical space change these cats noticeably. Boredom and depression look similar in cats, and both improve with the same measures.

When to come in

If the sleeping has increased noticeably over days or weeks. If your cat has stopped grooming, eating or greeting you. If it is hiding somewhere it never used to. If it is over seven and slowing down. Or if there is any weight loss, increased thirst or change in breathing.