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Urgent care is for pets who are unwell, in discomfort, are in urgent situation or are not acting like themselves and should be assessed within 24 hours.
Wellness, routine, or general care is for pets needing vaccines, preventive care, or ongoing monitoring who can safely wait at least 24 hours.
This page focuses on urgent assessment. Routine wellness exams, preventive care, and monitoring of stable conditions are provided through scheduled general wellness appointments.
Dog or Cat Overheated – Heatstroke Warning Signs
Heatstroke or heat exhaustion in dogs and cats can progress from mild weakness to rapid, life-threatening organ failure within hours, depending on body temperature, duration of heat exposure, and the pet’s ability to cool itself.
This condition is also searched as overheating, hyperthermia, heat illness, or collapsing from heat.
Definition
Heatstroke and heat exhaustion are medical emergencies caused by dangerous elevation of body temperature and are clinical conditions, not diagnoses.
In dogs and cats, heat illness occurs when heat generation exceeds the body’s ability to dissipate heat, leading to systemic inflammation and reduced blood flow to vital organs. As temperature rises, the brain, gastrointestinal tract, kidneys, heart, and clotting system may all be affected.
Because outward signs do not reliably reflect internal damage, veterinary assessment is essential even if cooling was attempted at home.
Who This Page Is For
• Dogs or cats exposed to hot environments, high humidity, or exertion
• Pets that suddenly become weak, lethargic, or collapse in warm conditions
• Pets with excessive panting, drooling, vomiting, or diarrhea after heat exposure
• Flat-faced, obese, senior, or medically compromised pets
• Pets that seemed fine but deteriorated hours after heat exposure
Who This Page Is Not For
• Pets briefly warm but otherwise normal with no behavior change, weakness, or distress
If you are unsure whether this is significant, that uncertainty itself warrants veterinary assessment.
Related Urgent Symptoms
• Sudden Collapse (Syncope)
• Seizures or Convulsions
• Difficulty Breathing (Respiratory Distress)
• Excessive Panting
• Dog Lethargic and Weak
• Cat Lethargic and Weak
• Pale Gums (Emergency)
• Toxin Exposure In Dogs And Cats
What This Can Look Like at Home
Heat illness may begin subtly and worsen quickly.
Owners may notice heavy or frantic panting, thick drooling, quiet or withdrawn behavior, vomiting, or loose or bloody stool. Some pets appear unsteady, confused, or suddenly collapse.
In cats, open-mouth breathing or hiding behavior may be the only early sign. Clinical signs are often subtle or masked at home, especially early.
Why This Can Be Hard to Judge
Body temperature alone does not reliably indicate severity.
Some pets appear improved after cooling but continue to develop internal organ injury hours later.
Humidity, breed anatomy, coat type, obesity, and underlying disease all affect risk. Apparent normalcy may not reflect internal changes, particularly in the first 24 hours.
The Improvement Trap
Temporary improvement does not equal resolution.
A pet may stand up, pant less, or seem “okay” after heat exposure while inflammatory damage continues internally.
Delayed complications such as clotting disorders, kidney injury, abnormal heart rhythm, or seizures may develop later the same day or overnight.
What Is Easy to Miss at Home
• Mild but persistent lethargy
• Decreased coordination
• Subtle gum color changes
• Reduced urine output
• Ongoing nausea without vomiting
• Quiet or hiding behavior
• Slower recovery than expected
These signs often indicate internal stress rather than simple overheating.
When This Can Be an Emergency
Heat illness requires urgent care if any of the following are present:
• Collapse or inability to stand
• Seizures or muscle tremors
• Vomiting or diarrhea (especially bloody)
• Pale, bright red, or blue-gray gums
• Heavy panting that does not settle
• Open-mouth breathing in cats
• Confusion, blindness, or abnormal behavior
• Weak or rapid pulse
• Known confinement in a hot environment
How Veterinarians Assess This
Clinical signs alone cannot reliably determine severity.
Symptoms can appear similar while representing very different internal disease processes. Diagnostic testing is how veterinarians determine whether heat illness is mild and self-limiting or serious and potentially life-threatening, and how they guide appropriate care.
Diagnostic testing may include:
• Complete blood count (CBC) to assess inflammation, anemia, platelets, and cellular injury
• Serum chemistry panel to evaluate kidney, liver, electrolyte, and muscle damage
• Blood glucose testing to detect hypoglycemia
• Coagulation testing to assess clotting ability
• Urinalysis to evaluate kidney injury and pigment changes
• Blood pressure measurement to assess perfusion
• Electrocardiogram (ECG) to identify heat-related rhythm disturbances
Additional disease-specific testing (such as imaging, lactate measurement, or repeat bloodwork over time) may be considered based on the overall clinical picture.
Diagnostic testing is what determines severity and guides appropriate care.
Veterinary Differentials - Serious / Must-Rule-Out First
• Heatstroke: Severe elevation of body temperature causing systemic inflammation and organ injury.
Tests may include CBC, serum chemistry, coagulation testing, blood glucose, urinalysis.
• Sepsis: Systemic inflammatory response that may mimic or complicate heat illness.
Tests may include CBC, chemistry panel, blood glucose, lactate testing.
• Toxicosis (eg, stimulants, tremorgenic toxins): Certain toxins can cause hyperthermia and neurologic signs.
Tests may include CBC, chemistry panel, toxicology screening.
• Status epilepticus: Prolonged seizures can cause dangerous hyperthermia.
Tests may include blood glucose, chemistry panel, imaging as indicated.
• Malignant hyperthermia: Rare inherited reaction often associated with anesthesia or stress.
Tests may include CBC, chemistry panel, muscle enzyme testing.
• Severe systemic inflammatory disease (eg, pancreatitis): Can present with collapse and hyperthermia.
Tests may include CBC, chemistry panel, abdominal imaging.
Veterinary Differentials - Common / More Typical
• Heat exhaustion: Earlier stage heat illness with weakness and anxiety without full organ failure.
Tests may include CBC, chemistry panel, blood glucose.
• Dehydration: Fluid loss reducing heat dissipation and circulation.
Tests may include PCV/TS, chemistry panel, urinalysis.
• Respiratory compromise: Brachycephalic or airway disease limiting heat loss.
Tests may include imaging, oxygen assessment.
• Cardiovascular disease: Reduced ability to compensate for heat stress.
Tests may include blood pressure measurement, ECG.
• Obesity-related heat intolerance: Increased heat generation and reduced cooling efficiency.
Tests may include CBC, chemistry panel.
Safety, Psychology, & Peace of Mind
Heat illness is dangerous because damage may continue after visible cooling.
Early assessment helps identify complications before they become irreversible.
Veterinary evaluation provides clarity, monitoring, and timely intervention. Same-day urgent care often prevents escalation and improves outcomes.
Frequently Asked Questions
Is heatstroke or heat exhaustion in dogs and cats an emergency?
Heatstroke or heat exhaustion in dogs and cats can range from mild to life-threatening, depending on duration of heat exposure and the pet’s ability to cool itself. Because outward signs do not reliably indicate severity or internal organ damage, this condition is treated as urgent. Same-day urgent care is recommended, especially if heat illness is accompanied by weakness, collapse, vomiting, seizures, or breathing changes.
My pet seems normal now — can heat illness still be serious?
Yes. Pets often hide illness, and heatstroke or heat exhaustion may temporarily improve even while internal injury continues to develop. Apparent normal behavior does not reliably reflect internal stability, particularly during the first 24 hours after heat exposure. Veterinary assessment is appropriate even if your pet appears improved after cooling.
What if it only happened once or seemed mild?
Even a single episode of heatstroke or heat exhaustion can be clinically meaningful. Temporary improvement does not equal resolution, and delayed complications such as kidney injury or clotting abnormalities may appear hours later. Early assessment helps determine whether heat illness is self-limiting or progressing.
Why are tests needed if we already know my pet overheated?
Clinical signs alone cannot determine severity. Diagnostic testing is how veterinarians identify internal organ involvement, assess complications, and distinguish heat exhaustion from dangerous heatstroke. Testing replaces uncertainty with clarity and guides appropriate care decisions.
What should I do right now?
Do not rely on watchful waiting. Heatstroke or heat exhaustion in dogs and cats warrants veterinary assessment, particularly if signs persist, recur, or include lethargy, weakness, collapse, vomiting, or abnormal breathing. Same-day urgent care helps reduce risk and determine next steps.