Minnesota Chapter of NAVHDA
Heatstroke in Dogs
The ‘dog days’ of summer typically bring some very high temperatures. With these high
temperatures, it is extremely important to prevent your dog from overheating. Your dog(s) cannot
tell you when their temperature rises and in fact, are so driven that they will run themselves into the
ground if you let them. Therefore it is your responsibility to ensure that your dog(s) have sufficient
shelter from the sun, adequate water to drink, a way of cooling off when the summer heat rises, and
to know when to pull them from the field before they have had enough. Please note that confining
areas such as crates, vehicles or trailers also present a danger.
Field conditions can also play an important part in heat stroke. Most everyone realizes how difficult
it is for the dog to breathe in thick, heavy cover. But the next time you feel only a slight breeze in
your face on a hot day, lay down in the thick cover with your dog to better appreciate what they
experience at their level. Also, I used to think that it was good to send the dog into the water for a
duck search on these hot days. I now realize that the thick duck search cover make it just as difficult
for the dog to breathe and can therefore be just as dangerous for the dog on a miserable day.
It seems that we handlers tend to drop our guard when the temperatures level off, either in the
Spring and Fall, thinking the dangers have passed. However, these milder temperatures combined
with high humidity can be every bit as dangerous. This is why we must focus on the Heat Index, not
just the obvious temperature.
The Heat Index
Heat index (or apparent temperature) is how the heat and humidity in the air combine to make us
feel. Higher humidity plus higher temperatures often combine to make us feel a perceived
temperature that is higher than the actual air temperature. The old saying, "its not the heat, its the
humidity" holds true. This heat and humidity combination reduces the dogs ability to regulate their
body temperature and outdoor exercise becomes a dangerous event, even for our highly conditioned
dogs. The heat index (or apparent temperature), is a guide to this danger. Below is the heat stress
index based on the apparent temperature.
Heat Index Chart
T
e
m
p
e
r
a
t
u
r
e
15
20
25
30
% Relative Humidity
35 40 45 50 55 60
110
108
112
117
123
130
105
102
105
108
113
117
122
130
100
97
98
102
104
107
110
115
120
126
132
95
90
85
80
91
93
95
96
98
100
104
106
109
86
87
88
90
91
92
95
97
81
82
83
84
85
86
87
76
77
78
78
79
79
80
65
70
75
80
85
90
113
119
124
130
98
100
103
106
110
114
117
121
88
89
90
92
81
82
83
84
94
96
97
100
102
85
86
87
88
89
Heat Index
80-89 degrees
90-104 degrees
105-129 degrees
130+ degrees
Caution: Fatigue is possible with prolonged exposure
and/or physical activity.
Extreme caution: Heat exhaustion is possible with
prolonged exposure and/or physical activity.
Danger: Heat stroke is possible with prolonged
exposure and/or physical activity.
Extreme danger: Heat stroke is imminent and the
risk is extremely high with continued exposure.
To use the chart, locate the air temperature along the left column and the relative
humidity along the top. The cell where the two intersect is the heat index.
For example, an air temperature of 90 degrees Fahrenheit and a relative humidity of
60 percent intersect at a heat index of 100 degrees. In other words, the temperature
would feel like 100 degrees with this humidity/temperature combination.
Heat index values were devised for shady light wind conditions. Exposure to full
sunlight can increase values by up to 15 degrees Fahrenheit.
Effects
A dog's body temperature is normally between 101°F and 102°F.
Dogs regulate their body temperature by panting, expelling heat out, causing an evaporatory
reaction. If they can not expel the heat fast enough, their body temperature rises. A rise of 3 degrees
in body to a temperature to 105°F is all it takes to send your dog into a dangerous situation. At this
temperature, the dog can no longer cope with reducing their body heat and the oxygen demand goes
up to where the dog can not keep up. Therefore, their temperature continues to rise.
When the temperature hits 108°F, the heart, brain, liver, kidneys, and intestinal tracts start to begin
breaking down at a cellular level, and the damage can progress at an alarming rate. Even immediate
treatment and effective cooling to bring his temperature down can leave the dog with internal
damage that may affect his health in long term ways.
Early Signs of Heat Stroke
Signs of early stages of heat stroke include rapid breathing, dry mouth and nose, rapid heart rate,
and gums that leave their healthy color for dull, grayish color. This grayish condition may also be
visible in the tongue or rectum.
This situation is an emergency! Even at the earliest stage of heat stroke, you may be fighting for
your dog's life. These symptoms can be followed in minutes by collapse, seizures, coma and death.
Field First Aid
If your dog is showing the first signs of heat exhaustion, rapid breathing, rapid heart rate, or grayish
gums the first thing you must do is remove them from the confining area or the field.
Take the dog to shade, and soak him with cool water. Do NOT use extremely cold or iced water.
This will cause blood vessels to constrict and will stop the heat from escaping.
You can apply ice packs to the areas underneath his front legs, and to the groin area for rapid blood
cooling. Give your dog enough water to wet his mouth and throat, but do NOT allow your dog to
drink copious amounts! You may also spray the paw pads with rubbing alcohol. This causes
immediate evaporation to help cool them off. Note: do not apply alcohol to other parts of the body
as this may cause other problems.
Take your dog's temperature, this is best done rectally to get the most accurate reading. If the
temperature is above 103 degrees, there is a good chance it is still rising. You should start to get
concerned at this point and prepare your dog for transport to the nearest vet clinic. Keep in mind
that your dog may need to be hospitalized.
Do NOT cover your dog, even with a cold towel. This will prevent the heat from escaping.
During transport, do NOT place him back in his crate, but keep him with you, with windows down
and air conditioning on high, to allow evaporation which will aid in the cooling process.
Yes, there is also a danger that dog can become too cold. Monitor the temperatures and stop the
cooling process as soon as your dog's temperature reads normally again.
Continue on the vet's, your dog is not saved yet!
Closing
What is the old saying? An ounce of prevention is worth a pound of cure?
Start to use the heat index as a guide to planning your work activities with your dog. Keep your
dogs well hydrated, give them adequate shade and ventilation, don’t over exert them in the field or
water when the heat index is high, and watch them closely so you know when to pull them before
they have had enough.