There are many types of dog cooling coat, but there is currently no scientific evidence that shows how well they work or whether they are more effective than a cool shower. The best advice is to avoid overheating in the first place. Ensure your dog’s coat is kept clipped and they have regular access to shade and fresh water. Never walk or exercise your dog at the warmest times of the day. If you would be uncomfortable wearing a coat outside, then it is too hot for your dog to be out.
A nice way to provide some relief from hot temperatures is to freeze a damp towel and allow your dog to lie on it. Some dogs may enjoy a cool, but not cold, shower. If dogs do overheat, they should be gently cooled with wet towels. Fast cooling with icy water can cause further illness. If you think your dog has heat stroke, contact your vet immediately for emergency advice and treatment.
In simple terms, temperature is a measure of the energy in a substance and the speed at which molecules in the substance are moving. The warmer an object, the faster the molecules move. Some move faster than others, but an overall kinetic energy level is determined. When the movement of water molecules is fast enough, then some escape the liquid state to become gas (water vapour) and this decreases the overall kinetic energy of the water, which is to say the temperature of the water.
When humans sweat, it is the evaporation of sweat (the escape of water molecules from liquid state to gas state) that cools us. A cooling coat (in which the dog stays dry) uses this change of state of water in hot conditions to continually lower overall kinetic energy or temperature of the water in the coat and reduce the temperature of the dog through conduction. It is clear that to work, the cooling coat must be wet. The coat must be re-wet when necessary or removed from the dog.
Especially given the frequent use of working dogs – often in extreme situations at high temperatures – it’s surprising that there is little fully evaluated scientific information on the prevention or treatment of heat stroke. There is also little understanding of how conventional rectal temperature relates to core temperature, and different individuals may show signs of heat stroke over a widely varying range of rectal body temperatures.
Research carried out on people is of limited value – the mechanisms by which dogs lose heat are different. Even the oft-repeated maxim not to use iced water for cooling the overheated has not been scientifically proven (which doesn’t mean it’s not true). And most of the research is based on young, fit and healthy dogs. The situation is different in the elderly, overweight or chronically sick, who are generally much less heat tolerant.
Dissipating heat by evaporation (largely from panting) is very important to dogs – but they can also cool down by reducing activity, getting out of the sun and lying on cold surfaces. Humidity (higher humidity reduces ability to cool down) and airflow influence the ability to cool by evaporation, but activity (the vigour and length) is also important. Dogs who are acclimatized (which takes 10-20 days) have a much better tolerance for heat.
Prevention is better than cure. Remember that an excited or highly motivated dog may not show the early signs of weakness, lethargy or confusion – and may forget to drink – so be sure to build rest periods into activity and to encourage your pet to drink. Remember that a muzzle will limit your pet’s ability to lose heat by panting.
It’s very uncertain whether cooling jackets offer an advantage in preventing heat stroke, but they do improve thermal comfort and ‘performance’ in human athletes. It also seems that cooling before and during exercise may allow a faster ‘recovery’.
But cooling vests aren’t essential and measures such as allowing rest in a cool place, wetting the dog’s coat and above all, providing lots of water and encouraging your dog to drink are as good. Hydration is vital. A cooling jacket will never be sufficiently reliable to allow you to take your pet to the park for a vigorous ball game in the heat of the day.
There are sometimes concerns that, when they dry out, cooling jackets might actually increase temperature. Again, it’s not scientifically proven,
but a study of military dogs wearing Kevlar vests at exercise found that their core temperatures didn’t go higher than those without. The same
study also found that cooling jackets seemed to allow the dogs to cool down more rapidly.