"If the conditions feel harsh to you, they are almost always worse for your dog. Dogs rely on panting, not sweating, to cool themselves — and that system has limits."— Dr. Michael LoSasso, DVM
Episode summary
Heat stroke is one of the most preventable emergencies Dr. LoSasso treats — and one of the most heartbreaking, because it progresses fast. In this episode, he explains exactly how dangerous Texas summers are for dogs, which breeds face the highest risk, and what owners can and cannot do at home when they suspect overheating.
His opening frame is simple and memorable: if the conditions feel harsh to you, they are worse for your dog. Dogs cannot sweat — they cool themselves entirely through panting — and that system has hard limits. In Texas, heat stroke can occur as early as April 1, and Dr. LoSasso says it doesn't require extreme temperatures: short walks during peak heat, intense play without shade, or just a few minutes of excitement can be enough for a high-risk breed.
He covers first aid in detail — including one of the most common mistakes: using ice water or very cold water on paws and legs, which can actually constrict blood vessels and slow cooling. Wetting the body helps; extreme cold on extremities does not. True treatment requires IV fluids, monitoring, and medications.
He also covers an underappreciated source of secondary heat stroke: prolonged seizures. When a dog has been seizing for 20-30 minutes, the muscle activity generates enormous internal heat — creating a combined emergency that requires immediate veterinary care.
"Once a dog's internal temperature rises above about 104°F, the danger escalates quickly. Severe cases can reach 110°F, and at that point, prognosis becomes poor."— Dr. Michael LoSasso, DVM
Heat stroke first aid — what to do and what NOT to do
Do: Move your dog to shade or AC immediately. Wet the body with room-temperature water. Drive to an emergency vet immediately — do not wait to see if they improve.
Do not: Apply ice or very cold water to paws and legs. This constricts blood vessels and slows cooling. Do not manage heat stroke at home.
Questions answered in this episode
The following questions are answered by Dr. LoSasso in this episode, drawn directly from the conversation. These are real clinical answers from a practicing emergency veterinarian with 30+ years of experience.
Dr. LoSasso says heat stroke progresses very quickly once it starts. When a dog's internal temperature rises above about 104°F, the danger escalates rapidly — damage to the brain, liver, gastrointestinal tract, and the body's clotting ability can occur within minutes at high temperatures. Severe cases can reach 110°F, at which point the prognosis becomes poor. In Texas, he has seen heat stroke cases as early as April 1, and it doesn't require extreme outdoor temperatures when the dog is high-risk.
Dr. LoSasso identifies brachycephalic breeds as highest risk — Boston Terriers, Pekingese, Boxers, and many Pit Bull-type dogs — because their airway structures make panting less efficient. Since dogs cool themselves primarily through the respiratory tract, anything that restricts airflow dramatically increases overheating risk during exercise, stress, or excitement. He also notes that heat stroke doesn't only happen to dogs left outside — he has treated dogs who overheated from fence running, rough play, or simply becoming overly excited.
Dr. LoSasso says to treat it as an emergency. Warning signs include collapse, extreme panting, weakness, bright red gums, and very red whites of the eyes. Move your dog to shade or air conditioning immediately. You can wet the body with room-temperature water to help cooling. Then go to an emergency vet immediately — do not wait to see if they improve on their own. Heat stroke is not something to manage at home; it requires IV fluids, monitoring, and medications.
Dr. LoSasso explains that while wetting the body helps, applying ice baths or very cold water to the paws and legs can actually backfire. Extreme cold constricts blood vessels in the extremities, slowing the return of cooled blood to the core and making the overall cooling process less effective. Room-temperature water on the body, getting the dog to a cool environment, and driving to the emergency vet are the right steps.
Yes — and this is an underappreciated risk. Dr. LoSasso explains that when a dog has been seizing for 20 to 30 minutes or longer, the intense sustained muscle activity generates enormous internal heat. The dog may be battling both a seizure emergency and secondary heat stroke simultaneously. That combination increases the risk of complications and makes rapid veterinary care even more critical than with seizure alone.
Dr. LoSasso recommends shifting outdoor time to early mornings and being cautious with evening walks — pavement holds heat long after the sun goes down and can burn paw pads. The test: if you wouldn't walk barefoot on it, your dog shouldn't either. Keep fresh water available at all times, avoid leaving dogs outside unattended, and in extreme heat, even 20 to 30 minutes outside can be too long without shade and hydration. Building a family routine so no one forgets the dog is outdoors prevents many tragedies.
JulieWhat should pet parents, especially dog owners, know about heat stroke?
Dr. LoSassoI hate heat stroke more than I hate anything else. It's an awful, awful problem. Here in Texas, we typically spend 20 or 30 days above 100 degrees as a high during summer — sometimes twice that. When it gets that hot, don't walk them during the heat of the day. I would personally only take them outside in the mornings. I don't even like walking them in the evenings. Concrete absorbs a tremendous amount of heat — you can burn foot pads pretty badly. If you wouldn't walk on the pavement because it hurts your bare feet, your dog has no business being out there. I had a patient brought to me a few years ago by police — not by the owner — because the owner walking the dog had been taken by ambulance for her own heat stroke.
Dr. LoSassoThe brachycephalic dogs — whether it's a Boxer, a Pit Bull, a Shar-Pei, a Boston, or a Pekingese — are much more prone to heat stress and heat stroke than other breeds. Dogs transfer all their heat through their respiratory tree. They breathe it out. They don't sweat anywhere — theoretically they sweat on their foot pads, which is almost completely useless. And those dogs with altered respiration because of their anatomy are super prone. About three years ago, my first heat stroke of the year was on April 1, and it was 70 degrees outside. It was a Boston Terrier who loved to run up and down the fence with the neighbor dog. He came in with a 107 to 108 degree body temperature.
Dr. LoSassoWhen you get that hot, your risk of serious damage to multiple organ systems escalates rapidly. Your brain does not like to be that hot. Your liver is frequently damaged. Your GI tract and intestines will be damaged. The most important one is actually the endothelium — the cellular lining of every blood vessel. When that gets damaged, you start to form micro-clots and then you run into all kinds of problems with the clotting cascade. It's complicated, it's expensive, and depending on how bad it is when we start, prognosis is generally not very good. We probably save half, maybe slightly more. It really depends on how hot they are and how long they were hot.
Dr. LoSassoGetting them wet is fine. But don't spend time putting them in a bathtub of ice water — cold water on the legs and feet causes blood vessels to shrink, and you don't get good blood flow or good temperature change. You've restricted blood flow to the limbs while the body is already shunting blood to the trunk. Just get them wet, then get them to us. They need IV fluids and medication. This is not something that should be handled at home. The biggest clinical signs are collapse — they won't want to get up, they're breathing really hard, and their gums may be bright red. Anything over 104°F and I want to see them. Normal dog temperature goes up to about 102.5°F. I have seen heat stroke at 105°F and I have seen it at 110°F. At 110, we have very little chance of saving that individual.
Dr. LoSassoEven just leaving a dog outside for 30 minutes in the heat of the day, unless there's really good shade and water, isn't safe. I can't tell you how many either severely affected heat stroke dogs or dogs brought to us already deceased because somebody left them out for a couple of hours. And a lot of times it's teenagers — it's really a family communication issue of 'hey, who let the dog out and who was supposed to let him back in.'
Dr. LoSassoThe other medical reason we see heat stroke is prolonged seizures. Dogs with really violent seizures have a huge amount of muscle activity. If they do that for 20 to 30 minutes, certainly for a couple of hours, they build up a tremendous amount of body heat. When somebody brings me a dog that's been seizing for two hours, we not only have to discuss how to treat the seizure disorder — we now also have to do emergency treatment for secondary heat stroke. That's a more complicated conversation and a less rosy outlook.
Dr. LoSassoThere's really no bigger emergency for us than heat stroke from a timeliness standpoint. I'll see a heat stroke before I'll see a GDV. We think of GDV as the mother of all emergencies — it's not. Heat stroke is a surgical problem we can fix. Heat stroke trumps everything that comes into an emergency hospital. It's an ugly problem.