Ask Dr. Jenn: My dog was outside all day and is acting funny. Could it be a heatstroke?

This summer has been extremely hot with places all over the United States experiencing record temperatures. With climate change, it is likely that our summer temperatures will continue to climb every year. These higher temperatures put our pets at risk for heat exhaustion and heatstroke.

First, what is heatstroke and how is it different than heat exhaustion? Both heat exhaustion and heatstroke occur when your pet overheats and the core body temperature rises to above a normal temperature (normal body temperatures for dogs and cats range from 100 to 102.5) Heat exhaustion is mild and occurs with a mild increase in body temperature. If your pet is experiencing heat exhaustion, you may see lethargy, mild weakness, and excessive panting. Heat exhaustion does not cause any major changes to the body and can be treated simply by bringing your pet to a cooler environment, such as an air-conditioned house.

Heatstroke occurs when the body’s core temperature reaches above 40 degrees Celsius, or 105.8 degrees Fahrenheit. At this temperature, the body releases proteins called cytokines. Cytokines cause widespread inflammation throughout the body, which leads to the breakdown of DNA, and cells throughout the body die. If untreated, multisystem organ failure occurs, along with widespread internal bleeding, and fluid build-up in the brain. The first sign of heatstroke is a change in your pet’s mentation. He may be stumbling when walking, not responding when you call his name, or acting like he is drunk. As heatstroke progresses, you will see bright red gums and bloodshot eyes and breathing loudly and with difficulty. Most animals will also experience sudden onset of vomiting and diarrhea.

Any animal can suffer heatstroke, but certain animals are at a higher risk. Dogs are much more likely to develop heatstroke than cats (perhaps this is because cats are smarter than dogs and choose to spend hot days sleeping on the couch instead of outside chasing a ball). Brachycephalic dogs, such as pugs, bulldogs, and Boston Terriers are more likely to develop heatstroke because their adorable squished faces make it harder for them to breathe.  Also, at a higher risk are dogs with breathing issues, such as laryngeal paralysis, collapsing trachea, or heart disease. The increased effort of breathing causes the body temperature to elevate much quicker. Overweight dogs and active dogs who have not acclimated properly to the heat are also at a higher risk.

If your dog is showing signs of heatstroke, it is important to cool his core body temperature. But you want to cool the temperature gradually, to avoid hypothermia (low body temperature) which can make his condition worse. You can immerse your dog in lukewarm to cool water or spray with a hose to start to bring the body temperature down. Do not dump ice or ice water on your dog as this rapid change in temperature causes further shock to his already stressed body. Fans or air conditioning can also help with cooling. Once you start the cooling process, call your veterinarian immediately. Your pet should be examined right away to determine if additional life-saving treatments are needed. While being transported to a veterinary hospital, I recommend placing cool wet towels around your dog’s feet. Dogs sweat through their pads and cooling their feet helps cool the rest of their body. Once you arrive at the hospital, your veterinary team will take over bringing your dog’s body temperature down and begin treatment of any secondary complications.

Heatstroke is a very serious condition that can have long-term complications and may result in death, even if treatment is started immediately. The best way to treat heatstroke is to prevent it from happening. But how do we do that in the middle of a heatwave? We all know not to leave our pets in a car on a hot day. But heatstroke in a car can even occur on a mild day and with the windows open. Avoid taking your dog or cat in the car when you know you will have to leave them in the car for any period of time. If you must leave your pet in the car, make your stop short, park in a shady area, and either leave the windows down or keep your car running with the air condition on. If your dog likes to be outside, make sure he has access to shade and cool water at all times. Many pet owners will purchase kiddie pools for their dogs to cool off in on hot summer days. If it’s a hot and humid day, limit your pet’s exercise and make sure he takes plenty of water breaks.

Most pet owners are aware of the risk of heatstroke during the extremely hot and humid days of July and August, but heatstroke is also a higher risk during the early days of summer when the outside temperature doesn’t seem that concerning. But during the first few warm days of spring and summer, heatstroke can occur when our pets haven’t had time to acclimate to the sudden increase in temperature. Your dog may still have his winter coat or his body hasn’t adjusted to the sudden rise in temperature. Check on your pet often during the first few warm days of spring and summer. Take him out for only short periods of time to allow his body to adjust to rising temperatures. Limit exercise. Make sure that he has a shady spot to get out of the sun.

Although we talked mainly about dogs, a lot of this information applies to humans as well. Keep yourself well hydrated and cool during these hot summer months. Maybe the best way to make it through a heatwave is for you and your four-legged friend to take an evening stroll to the local ice cream shop – a scoop of chocolate for you and a scoop of vanilla for Buddy.