Most of the time, a cat shaking or twitching during sleep is completely normal. Cats spend a significant portion of their sleep in REM (rapid eye movement) cycles, and small involuntary movements during this phase are a sign of healthy, deep sleep. That said, there are a few situations where shaking during sleep points to something that needs attention.
What Normal Sleep Twitching Looks Like
During REM sleep, cats experience the same kind of brain activity they have while awake. Their bodies are mostly paralyzed to prevent them from acting out dreams, but small movements break through. These are the twitches you’re likely noticing, and they can include whisker twitching, ear flicking, paw movements that look like batting at a toy, tail swishing or thumping, and subtle facial expressions. Your cat’s eyes may also be moving rapidly beneath closed lids.
Cats sometimes vocalize during REM sleep too. Small meows, chirps, or chattering sounds are all normal. If your cat is curled up, breathing steadily, and making these kinds of gentle movements, they’re almost certainly just dreaming. The twitching tends to come in brief bursts, lasting a few seconds at a time, and your cat can be easily woken if you call their name or touch them.
Kittens Twitch More Than Adults
If you have a kitten, expect to see a lot more sleep twitching than you would in an adult cat. Kittens’ nervous systems are still developing, and these involuntary movements during sleep are thought to play a role in building neural pathways and muscle coordination. The twitching can look almost constant in very young kittens, sometimes involving their whole body. This is normal and typically decreases as they mature.
When Shaking Means Your Cat Is Cold
Cats have a normal body temperature range of roughly 98 to 102°F (36.7 to 38.9°C), which is higher than humans. That means environments comfortable for you can sometimes feel cool to your cat, especially if they’re small, thin, elderly, or short-haired. Shivering during sleep in a cold room is your cat’s body trying to generate heat through rapid muscle contractions.
This is easy to test. If the shaking stops when you add a warm blanket or move your cat to a warmer spot, temperature was the issue. Persistent shivering that doesn’t respond to warmth, or shivering in a warm environment, suggests something else is going on. Low body temperature in cats can also result from more serious problems like cardiac issues or shock, so cold-related shivering that doesn’t resolve quickly is worth investigating.
Low Blood Sugar Can Cause Trembling
Hypoglycemia, or low blood sugar, is one medical cause of shaking that can be more noticeable when a cat is resting. It occurs when blood glucose drops to 60 mg/dL or lower. The early signs can be subtle: your cat may seem hungrier than usual, restless, or unusually quiet and uninterested in food. Shivering is one of the earlier physical symptoms, followed by incoordination and disorientation if blood sugar continues to drop.
This is most common in diabetic cats receiving insulin, but it can also happen in kittens who haven’t eaten enough or in cats with certain liver or pancreatic conditions. If your cat is shaking and also seems wobbly, confused, or lethargic when awake, low blood sugar is a real possibility.
Toxin Exposure and Muscle Tremors
Certain household products can cause persistent tremors in cats that continue even during rest. The most dangerous and common culprit is permethrin, an insecticide found in many flea and tick products designed for dogs. Permethrin is highly toxic to cats. In a large UK study, 86% of cats with permethrin poisoning showed tremors or uncontrolled muscle twitching, and 33% had seizures. Other signs include extreme sensitivity to touch, drooling, loss of coordination, and in some cases temporary blindness.
Even mild permethrin exposure from direct skin contact can cause paw flicking, ear twitching, and uncontrolled contractions of the skin muscles along the back. If you’ve recently applied a flea product (especially one meant for dogs), used a household insecticide, or your cat has been near treated surfaces, this is an emergency. Wash the product off immediately with dish soap and get to a veterinarian right away. Permethrin poisoning can be fatal without treatment.
Pain That Shows Up During Sleep
Cats are notorious for hiding pain while awake. During sleep, when their guard is down, discomfort from conditions like spinal arthritis, disc problems, or skin issues (parasites, allergies, fungal infections) can manifest as twitching, trembling, or restlessness. A condition called feline hyperesthesia syndrome causes episodes of exaggerated skin sensitivity along the back, which can trigger rippling skin, muscle twitching, and agitation. It’s more common in younger cats.
Pain-related shaking is usually accompanied by other behavioral changes you might notice during waking hours: reluctance to jump, changes in grooming habits, irritability when touched in certain areas, or a shift in sleeping positions. If the shaking seems localized to one part of the body or your cat reacts when you touch a specific area, pain is worth considering.
How to Tell Normal From Concerning
The key distinction is whether your cat responds normally when woken up. A dreaming cat will open their eyes, look at you, stretch, and go about their business. The twitching stops immediately once they’re awake. A cat experiencing a seizure, toxin exposure, or severe metabolic problems will be difficult or impossible to rouse, may appear stiff or rigid rather than loose and relaxed, or will continue trembling after waking.
Other red flags include shaking that involves the whole body with stiffness, loss of bladder or bowel control during an episode, drooling or foaming at the mouth, shaking that lasts longer than 30 seconds continuously, and any sign of confusion or disorientation after waking. If your cat shakes briefly, wakes up fine, and acts normal afterward, you’re almost certainly watching a healthy cat dream. If any of those warning signs are present, contact your veterinarian promptly.