Exercise Induced Collapse is a troubling and still barely understood condition that affects a number of breeds, primarily the Labrador Retriever. There are several conditions that are triggered by intense exercise, heat, or a combination that are often conflated. One form of exercise intolerance, called Border Collie Collapse (BCC), can particularly affect Australian Shepherds.
Either condition can come on suddenly in a dog that may otherwise seem perfectly fit and healthy. Symptoms usually manifest after about 15 minutes of vigorous activity, such as herding work or participating in agility trials. Sometimes a bout of EIC or BCC won't occur until after the exercise session is over.
There are other conditions, including Exercise Induced Hyperthermia (EIH) and heat exhaustion/heat stroke that are similar in nature but they should not be confused with EIC or BCC. Whereas EIH and heat exhaustion/heat stroke all involve an inability of the dog's body to properly cool itself when overheated, EIC and BCC directly affect the muscles. The only thing all of these conditions do share is the fact that they can be brought on by strenuous exercise and are more likely to occur during warm weather.
In order to clear up the confusion let's look at each of these conditions separately:
Exercise Induced Collapse (EIC) — this is a condition where the nerves fail to properly send signals to the muscles causing the muscles to stop responding normally. EIC can occur in any kind of weather as it is triggered by physical exertion rather than temperature. After about 15 minutes or so of exercise, including herding work or agility practice or competition, dogs with EIC will begin to exhibit a wobbly gate. The dog may appear to be dragging its hind legs or be unable to use its legs at all. In some cases, the affected dog may look disoriented and fail to respond normally. Usually the dog will regain normal function in anywhere from 5-30 minutes after the onset of symptoms.
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Keep an eye on your Aussie and make sure they are not over-exerting themselves.
Recent studies have also discovered that EIC, common to Labrador Retrievers, has been directly related to a particular gene mutation for which a test is now available. No such specific correlation has been made in any other breed but studies are ongoing.
Border Collie Collapse (BCC) — at one time the label "Border Collie Collapse" was also applied to EIC but now the two are being considered different conditions, with BCC specifically affecting Border Collies as well as Australian Shepherds, Bearded Collies, Collies and Shetland Sheepdogs. The symptoms are generally the same and, like EIC, scientists believe that a genetic mutation may be the underlying cause of the condition, though this has yet to be confirmed. At the time of this writing there is no test available for BCC.
Exercise Induced Hyperthermia (EIH) — Though it too can be brought on by bouts of extreme physical exertion, EIH should not be confused with EIC or BCC. Unlike the other conditions, EIH is characterized by an elevation in body temperature. EIH can affect any breed and usually occurs when a dog has been exercising in warm weather.
In healthy dogs, as the body heats up during exercise it is cooled down naturally by sweating through the paws and by panting. When the dog's body is unable to eliminate that build up of heat fast enough, he can develop EIH. Dogs suffering from EIH will exhibit symptoms such as excessive panting, excessive drinking and drooling. In extreme cases, EIH can lead to collapse, seizures and temporary blindness. Unlike Exercise Induced Collapse, where affected dogs will usually recover within 30 minutes of the onset of symptoms, in EIH recovery can take hours.
Heat exhaustion/heat stroke — Like EIH, heat exhaustion and heat stroke are described as an unusual spike in body temperature not caused by a fever or infection. Unlike EIH, this severe overheating doesn't necessarily have to be the result of excessive exercise although that is certainly one potential cause. Other causes can include excessive levels of thyroid hormones and lesions in the hypothalamus, the region of the brain that controls body temperature.
Though heat exhaustion, heat stroke and EIH are all more prevalent in thick coated and short nosed breeds that would have more difficulty eliminating excess heat due to their physical characteristics, it can occur in any breed. As with any condition that involves a serious elevation in temperature, heat exhaustion/heat stroke can be fatal if not treated properly.
Though there is still much to be learned about the specifics of Exercise Induced Collapse and Border Collie Collapse, what is known for sure is that both are more common among certain breeds, like the Australian Shepherd with BCC, that tend to be highly driven. These are breeds that have a natural working instinct that makes them highly prized among ranchers and farm owners for their durability and reliability. Unfortunately, these dogs also have no off switch. They function at full speed all the time and will continue to do so unless made to stop.
For this reason, owners of these breeds need to be particularly cautious about overworking. Even though your dog may seem eager to keep going, it is up to you to know when enough is enough and to make sure he slows down and gets the proper rest and hydration. Until more is learned about the specific causes of Exercise Induced Collapse and Border Collie Collapse this is the best approach you can take to help prevent occurrences. This same caution will help you to guard against Exercise Induced Hyperthermia and heat stroke as well.
As owners of Australian Shepherds know, these are highly intelligent, active, and enthusiastic dogs. They will give you their all at all times, but sometimes they can actually give too much. Whether you are working with your herd, running agility trials, or playing all-out at the park, you need to be aware of your canine companion's health and make sure he isn't overdoing it, no matter how anxious he may be to please you. A little extra caution can make all the difference and keep your Aussie functioning at his absolute best.