If your dog is shaking and lethargic at the same time, it’s natural to feel concerned. Shaking in dogs can range from mild tremors to full-body shivers, and lethargy typically means your dog is unusually tired, weak, or uninterested in their usual activities.
While either symptom alone might have a benign explanation, together they could signal a more serious health concern.
We outline the reasons why your dog is shaking and lethargic, what other symptoms to watch for, and when to seek help from your vet.
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Here’s Why Dog Shaking and Lethargic Behavior Happens
When a dog is shaking and lethargic at the same time, it can be a sign of an underlying health issue that requires immediate attention. These symptoms may result from pain, poisoning, infection, low blood sugar, organ dysfunction, or severe anxiety.
Shaking often signals discomfort or distress, while lethargy—marked by low energy or reluctance to move—indicates that the dog’s body is not functioning normally.
Together, these signs suggest the dog’s system may be under serious stress.
If your dog is both shaking and lethargic, it’s important to monitor other symptoms such as vomiting, pale gums, or loss of appetite, and seek veterinary care promptly.
Dog shaking refers to involuntary movements, often due to cold, fear, excitement, or medical issues.
Lethargy in dogs is a noticeable drop in energy levels—your dog may be sleeping more, moving slower, or ignoring food and play.
When a dog is both shaking and lethargic, it often indicates an underlying problem. It could be something minor, like temporary stress, or a more serious issue like poisoning, pain, infection, or organ dysfunction.
Common Causes of Dog Shaking and Lethargy
1. Pain or Injury
One of the most overlooked causes of a dog shaking and acting lethargic is pain.
Dogs instinctively try to hide pain, but involuntary trembling and lack of movement can be telling signs.
Muscle strains, broken bones, or internal injuries may cause your dog to shake due to discomfort and become lethargic from trying to limit movement.
Dogs in pain might also yelp, resist being touched, or favor a limb.
If your dog is shaking and lethargic with no obvious cause, it’s wise to consider the possibility of a hidden injury or chronic pain.
Related: Dog shaking and panting for no reason (Explained)
2. Poisoning or Toxin Exposure
Dog shaking and lethargy after ingesting something toxic is a serious emergency. Ingesting harmful substances—like chocolate, xylitol, medications, certain plants, or pesticides—can quickly impact your dog’s nervous and digestive systems.
Common symptoms of poisoning include:
Vomiting or diarrhea
Tremors or full-body shaking
Extreme fatigue or collapse
Drooling
Seizures
Toxin-related symptoms often escalate rapidly.
If your dog is lethargic and shaking and you suspect they’ve consumed something unusual, seek emergency veterinary care immediately.
3. Hypoglycemia (Low Blood Sugar)
Small breeds, puppies, and diabetic dogs are particularly prone to hypoglycemia.
When a dog’s blood sugar drops too low, they may become disoriented, lethargic, and start shaking.
Other signs include:
Seizures
Confusion
Weakness
Lack of coordination
Feeding a small amount of food or rubbing a bit of corn syrup on their gums (only if safe and advised by a vet) can help raise blood sugar levels temporarily.
Persistent symptoms require urgent veterinary attention.
Related: Dog diarrhea and shaking (Explained)
4. Infections and Fever
Dog shaking and lethargic behavior may result from an underlying infection.
Whether it’s bacterial, viral, or parasitic, many infections trigger fever, weakness, and shivering.
Examples include:
Parvovirus
Kennel cough
Lyme disease
Urinary tract infections (UTIs)
Tick-borne illnesses
Fever often causes dogs to shake as their body tries to regulate temperature.
Lethargy comes from the body’s effort to fight off the infection.
If your dog is shaking and lethargic along with symptoms like vomiting, coughing, or nasal discharge, an infection may be the cause and warrants a vet visit.
5. Addison’s Disease
Addison’s disease is a hormonal disorder caused by the body’s inability to produce enough cortisol.
It often presents as vague symptoms, making it tricky to diagnose early.
Common symptoms of Addison’s in dogs include:
Lethargy
Muscle tremors
Shaking
Diarrhea
Vomiting
Collapse in severe cases
Addison’s flare-ups are called Addisonian crises and can be life-threatening.
If your dog is shaking, lethargic, and shows signs of distress, call your vet right away.
6. Nausea or Gastrointestinal Distress
Dogs experiencing nausea or upset stomach may shake and act tired. This is often due to:
Dietary indiscretion (eating spoiled food or garbage)
Inflammatory bowel disease (IBD)
Gastroenteritis
Intestinal blockage
In these cases, dogs may also drool, vomit, or refuse food. A dog shaking and lethargic due to stomach issues often shows signs of discomfort like whining, curling up, or pacing.
7. Anxiety or Fear
Fear and anxiety are common triggers for dog shaking, especially in sensitive breeds.
During thunderstorms, fireworks, vet visits, or car rides, some dogs experience intense fear responses.
Symptoms of fear-based shaking may include:
Panting
Trembling
Pacing
Avoidance
Flattened ears
However, when combined with lethargy, it may indicate the dog is emotionally shut down or exhausted by prolonged stress.
If your dog frequently shakes and acts lethargic during stressful situations, behavioral training and calming strategies may help.
8. Cold or Hypothermia
Cold weather or being wet in low temperatures can cause dog shaking and lethargy.
Smaller or short-coated dogs are especially vulnerable to hypothermia.
Signs of hypothermia include:
Full-body shivering
Weakness
Slow breathing
Pale or blue gums
Lethargy
If you suspect your dog is too cold, bring them indoors, dry them off, and wrap them in a warm blanket. Severe cases require veterinary care.
9. Neurological Disorders
Certain neurological conditions such as canine epilepsy, tremor syndrome, or intervertebral disc disease (IVDD) can lead to both tremors and fatigue.
Neurological causes often present with:
Muscle weakness
Incoordination
Seizures
Behavior changes
If your dog is shaking and lethargic with signs of neurological dysfunction, a vet evaluation is essential.
Other Symptoms to Watch For
When your dog is lethargic and shaking, look out for these additional warning signs:
Vomiting or diarrhea
Refusal to eat or drink
Breathing difficulties
Excessive drooling
Rapid heart rate
Swollen abdomen
Gums that are pale, blue, or bright red
Sudden collapse
These can help your vet determine the severity and underlying cause of the symptoms.
What to Do If Your Dog Is Shaking and Lethargic
Stay Calm: Dogs pick up on human anxiety. Stay composed while assessing your dog.
Monitor Symptoms: Keep track of when the symptoms started and if they’re getting worse.
Check for Toxins: Look around for signs your dog may have gotten into something harmful.
Keep Them Comfortable: Provide a warm, quiet environment. Avoid forcing them to eat or move.
Contact Your Veterinarian: If your dog continues shaking and acting lethargic for more than an hour, or if additional symptoms arise, seek immediate veterinary care.
When to Seek Emergency Care
Go to the vet immediately if:
Your dog is shaking and lethargic for more than a few hours
There’s vomiting or diarrhea involved
You suspect poisoning
They collapse, have seizures, or lose consciousness
Your dog is a puppy, senior, or has a chronic illness
Delaying treatment could allow a serious condition to worsen.
Key Takeaway: Dog Shaking and Lethargic
A dog shaking and lethargic isn’t something to brush off.
While minor issues like fear or mild stomach upset can be harmless, these symptoms together can also point to pain, poisoning, infection, or more severe medical problems.
If you notice your dog is shaking and unusually tired, observe them closely, check for other symptoms, and consult your veterinarian promptly.
Early intervention can mean the difference between a quick recovery and a more serious complication.
Keeping your dog safe, comfortable, and healthy starts with recognizing changes in their behavior—and acting quickly when something seems off.