About exercise-induced collapse (EIC)
A syndrome of exercise intolerance and exerciseinduced
collapse (EIC) is being observed with
increasing frequency in young adult Labrador
retrievers. It has also been observed in
Chesapeake Bay and curly-coated retrievers,
as well as Boykin Spaniels, Pembroke Welsh
Corgis, and German Wirehaired pointers.
Affected dogs have been found in fi eld-trial, hunt
test, conformation, pet, and service lines. Black,
yellow, and chocolate Labradors of both sexes are
affected, with the distribution of colors and sexes
closely refl ecting the typical distribution in the
population.
Signs fi rst become apparent in young dogs, usually
between 5 months and 3 years of age (averaging
14 months). In dogs used for fi eld trials, this
usually coincides with the age at which they enter
heavy training. Littermates and other related dogs
are commonly affected, but depending on their
temperament and lifestyle, they may or may not
manifest signs. Affected dogs exhibiting signs of
collapse are usually described as being extremely
fi t, muscular, prime athletic specimens of their
breed with an excitable temperament and lots of
drive.
Description of exercise-induced collapse
Affected dogs can tolerate mild to moderate exercise,
but 5 to 20 minutes of strenuous exercise with extreme
excitement induces weakness and then collapse.
Severely affected dogs may collapse whenever they
are exercised to this extent; other dogs only exhibit
collapse sporadically. The factors important in inducing
an episode can vary among dogs.
The fi rst thing noted is usually a rocking or forced
gait. The rear limbs then become weak and unable
to support weight. Many affected dogs continue to
run while dragging their back legs. Some of the dogs
appear to be incoordinated, especially in the rear
limbs, with a wide-based, long, loose stride rather
than the short, stiff strides typically associated with
muscle weakness. In some dogs, the rear limb collapse
progresses to forelimb weakness and occasionally to
a total inability to move. Some dogs appear to have
a loss of balance and may fall over, particularly as
they recover from complete collapse. Most collapsed
dogs are totally conscious and alert, still trying to run
and retrieve, but affected dogs can appear stunned or
disoriented during the episode. It is common for the
signs to worsen for three to fi ve minutes even after
exercise has been terminated.
Most dogs recover quickly and are normal within 5
to 25 minutes with no residual weakness or stiffness.
Dogs are not in pain during the collapse or after
recovery. Affected dogs are not stiff or sore or limping
upon recovery.
Note: A few affected dogs have died during exercise
or while resting immediately after an episode of
EIC, so an affected dog’s exercise should always
be stopped at the fi rst hint of incoordination or
wobbliness.
Factors contributing to collapse in dogs
with EIC
Ambient temperature
The ambient temperature does not seem to be a
critical factor contributing to collapse, but if the
temperature is much warmer or the humidity is much
higher than the dog is accustomed to, collapse may be
more likely. Affected dogs are less likely to collapse
while swimming than when being exercised on land.
There are severely affected dogs, however, who
have exhibited collapse while breaking ice retrieving
waterfowl in frigid temperatures, and some dogs have
drowned when experiencing EIC-related collapse in the
water.
Excitement
Dogs that exhibit signs of EIC are most likely to have
intense, excitable personalities, and it is very apparent
that their level of excitement plays a role in inducing
the collapse. There are some severely affected dogs
who require very little exercise to induce the collapse.
Dogs with EIC are most likely to collapse when
engaging in activities that they fi nd very exciting or
stressful. This can include retrieving of live birds,
participation in fi eld trials, training drills with electric
collar pressure, and quartering for upland game.
Type of exercise
Routine exercise like jogging, hiking, swimming, most
waterfowl hunting, and even agility or fl yball training
may not induce an episode in dogs with EIC. Activities
with continuous, intense exercise, particularly
if accompanied by a high level of excitement or
anxiety, most commonly cause collapse. Activities
commonly implicated include grouse or pheasant
hunting, repetitive “happy retrieves,” retrieving drills
or repetition of diffi cult marks or blinds where the dog
is being repeatedly corrected or is anticipating electric
collar correction, and running alongside an ATV.