A brown-haired dog pants in the sunlight

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.

Those at greatest risk of heat-related illness include:

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

Precautions include the following: