Dangerous Conditions: How Heat and Humidity Affect Your Dog

You checked the temperature before taking your dog out on a morning run. When the door opens, however, the two of you are greeted by a blast of heat. The temperature seems much hotter than it actually is.

Although the thermometer may read 75 degrees Fahrenheit, the Temperature-Humidity Index makes it feel much hotter. The index is a term used since 1959 to indicate the degree of discomfort caused by the combination of temperature and humidity in warm weather. The Temperature-Humidity Index (usually just called the Heat Index) is like the wind chill factor during winter when the wind makes the temperature feel colder than it actually is.

Temperature and humidity (the amount of water vapor in the air) are factors translated by equations into an index that ranges from 43 to 103. In humid air, perspiration does not evaporate as readily, making it difficult for people and animals to cool down efficiently. As the humidity increases, the environment feels warmer than it actually is. This perception is expressed by the heat index. An apparent temperature, or heat index, of 105 F can be reached when the air temperature is only 90 F, and the relative humidity is 70 percent.

An apparent body temperature of about 105 F makes heat stroke possible. With a heat index of 130 F or higher, heat stroke is extremely likely. It does not take extremely high ambient temperatures to produce heat-related illnesses.

Heat-related illnesses include heat stroke, heat exhaustion and heat cramps, and can occur after exposure to extremely high environmental temperatures. All of these illnesses can occur in all mammals and all can be prevented by taking adequate precautions.

Heat-Related Illness: At-Risk Dogs

Those at greatest risk of heat-related illness include:

• Puppies and kittens up to 6 months of age
• Geriatric pets (large breed dogs over 7 years of age, small breed dogs over 14 years of age, cats over 12 years of age)
• Pets who are overweight
• Pets who overexert during work or exercise
• Pets who are ill or on certain medications
• Brachycephalic pets (such as bulldogs or pugs) or pets with a history of an airway obstruction
• Those with fever, dehydration, heart disease or poor circulation

Preventing Heat-Related Illness in Dogs

Use precautions to avoid heat injury in your pet during the following conditions:

• Temperatures greater than 100 degrees (use general precautions for at-risk pets at 90 degrees)
• Heat index greater then 7 2 (start precautions for at-risk breeds)
  Heat index great than 75 (use absolute precautions for at-risk breeds)

Precautions include the following:

• Keep pets in well ventilated areas.
• Provide exercise early in the morning or late in the evening (the coolest times of the day).
• Minimize exercise in hot weather.
• Do not leave your pet in a car for any reason at any time.
• Keep pets in the house in a comfortable environment during extreme weather conditions if possible.
• Limit sun exposure during the mid-day hours.
• Give your pet plenty of fresh water, and leave the water in a shady area.
• For a sudden high temperature change – allow your pet to acclimate. Many cases of heat illness occur in the spring when your pet is not yet used to the new temperatures.
• If traveling to a hotter climate, allow several days to become acclimated before allowing any vigorous exercise for your pet; work up to it gradually.
• Ensure that puppies and kittens drink adequate amounts of liquids.