Active cooling during exercise, or between bouts of exercise, has been shown in a few studies to regulate body temperature and increase endurance in dogs during exercise. One study from 1985 showed that dogs running while wearing ice packs demonstrated significantly better endurance. You can read more about that study here: Effect of Cooling 1985 Study. Another study showed that when dogs were actively cooled immediately after repeated strenuous runs on a treadmill, compared to when they were made to passively cool (resting for 30 minutes in a kennel), their body temperatures remained at a lower value for longer during their next run.
This concept has recently been revived and several studies are currently being conducted on the topic. Our experience has shown us that active cooling- even when the dog does not appear “too hot,” seems to improve endurance and allow the dog to work longer during the course of the day. The key there seems to be not waiting until the dog appears “too hot.” He has worked hard, exerted himself hard during exercise, and is panting heavily, yet appears alert and ready and willing to keep going. Pull him off line for a few minutes, cool him down with an active cooling method, and get him back out to work.
So what is “active cooling?” Active cooling methods involve applying something cooler than the dog, to the dog directly to facilitate transfer of heat from the dog to the cooler object. In contrast, “passive cooling” is allowing the dog to simply rest and dissipate body heat naturally without any additional “help.” These definitions are not black and white, as there is a grey area between active and passive cooling. Allowing the dog to rest on a cool floor in an air conditioned building, for example, or in an air conditioned vehicle, blur the lines between active and passive cooling. But for the purpose of this description, we’ll define active cooling as where you take some specific action to cool the dog down by either applying a cool substance (water, ice) or allowing the dog to soak in a water source themselves.
When using water for active cooling, we’ll typically use water from a regular garden hose (let the sun-heated water run out first!), and add a little help from a cooler full of ice slush that we sponge over the dog’s back. Now, I know that last line got a few gasps and thoughts of “no way!” Ice water has long been demonized as detrimental to cooling in dogs, but there’s really no evidence that this is truly detrimental, especially in routine cooling. The laws of physics say that if you put something cold on something hot, the hot thing will transfer heat to the cool thing, so regardless of what was ingrained in our heads for years about the evils of ice water in cooling dogs, the dog will still get cooler. He’ll feel better, get back to work faster, and another myth will be busted.
Another well-intended, but never validated concern with cooling with water is that water standing between the skin and fur will create a sort of “wet suit” effect, actually insulating the dog and holding in the heat. When you saturate a hot dog’s fur with water, you can feel the water warming up, so maybe there’s something to this (it’s never actually been studied), but to prevent this potential problem, repeatedly soak the dog, wipe the water away, and apply more water, sort of wiping the heat away with it.
Inexpensive kiddie pools and livestock water troughs are relatively portable items that you can take to the field to canine trials or field training sites, although the water may be harder to transport if no hose is available. Natural water sources are good options, too, with common sense safety measures. Place pools or troughs in common areas of the event, and a portable canopy shade over the top or natural shade will help keep the sun from warming the water. When you don’t have access to a pool or trough, small “six-pack” coolers with ice slush and a few sponges or hand towels work well for portable cooling stations. We’re serious- Ice water is not the enemy. This method is commonly used in Special Operations military working dogs and other elite canine athletes to keep them cool in training.
Dogs’ rectal temperature will continue to climb even after stopping exercise, so remember that if you stop your dog working and his temperature is 104° F (40° C), his temperature may keep climbing to even over 105° F (40.6° C). That’s another benefit of active cooling- you can help prevent the continuous climb of his temperature to possibly dangerous levels. Finally, when choosing a thermometer for your dog (a must-have item in your readily-available equipment), get a digital thermometer that reads in 10 seconds or less. Look for the statement on the packaging for the length of time it takes to give a reading. If it only says “Fast-reading,” but no specific time in seconds, it means 60 seconds!