We all enjoy spending time outdoors in the summer with our dogs, but it is important to keep them hydrated and cool just like we do for ourselves. Unlike us, our four-legged companions don’t sweat to cool themselves. While we see them panting, we may not realize the amount of water they are actually losing. They lose water and release heat through a process called evaporation, which is the endothermic process of a fluid changing to a vapor.
Dogs bring large quantities of air in contact with the mucosal surfaces of the nose and mouth by panting; this allows them to release heat primarily by evaporation. Your dog's ability to cool himself through this method effectively decreases as humidity increases; therefore, it is important to consider the heat index. The heat index combines air temperature and relative humidity in an attempt to determine what the temperature “feels like” to our bodies. So, while we are sweating away and realize we are becoming dehydrated, we don’t realize that “Fido” is also dehydrated. Once dehydrated, dogs are less able to cool themselves through evaporative cooling. Much like a car without water in the radiator, dogs will rapidly overheat and suffer from heat stroke.
There are several things that can be done to help maintain adequate hydration and avoid heat stroke. First, make sure your dog has plenty of fresh water before, during and after being outside. If you are planning on taking your dog out for an extended period of time, bring along water and offer it every 15-30 minutes. Plenty of pet-friendly water bottles with dishes are available online or in your local pet and sporting goods stores.
Symptoms of dehydration include the gums feeling tacky to the touch and the skin becoming slow to return to its natural position when pulled up. Other signs include excessive panting and a rapid heart rate. It is a good idea to evaluate your dog before going out so you have an idea of what his normal hydration is like. That being said, most veterinarians find it difficult to determine when a dog is less than five percent dehydrated. Therefore, if you feel your dog is dehydrated, it is better to err on the side of caution. Stop your activity, offer your dog water and find a cool place in the shade for him to recover.
Also, to avoid dehydration in the summer sun, avoid activity in the middle of the day and allow your dog time to get used to warm temperatures. In other words, don’t take him for a long walk on the first warm day of the year. Also, always consider your dog’s health and breed. Dogs with heavy coats, pre-existing respiratory conditions (whether acquired or inherited) or who are overweight are at a higher risk for having trouble as temperatures and humidity increase.
This summer while you and your four-legged companion are out enjoying the weather, remember to keep his hydration and the forecast in mind. Pay careful attention to cues your dog may give that he is overexerting himself in the heat. It is better to underestimate your dog's fitness and overestimate his dehydration than to take a chance with heatstroke, which can have terrible consequences.
Written by Thomas Linnenbrink, DVM
Dr. Tom Linnenbrink has practiced veterinary medicine for more than 12 years. He completed his undergraduate studies in biology at Colorado State University and received his Doctorate of Veterinary Medicine from Colorado State University’s School of Veterinary Medicine in 2001. He worked as an intern in medicine and surgery at Texas A&M University College of Veterinary Medicine before moving to Rochester, New York, to work as an emergency staff clinician, at Veterinary Specialists and Emergency Services.