Extreme Heat and Heat-Related Illnesses

Summer temperatures in Virginia normally climb into the upper 90’s and even reach higher than 100 degrees at times. The hot temperatures and high heat indexes can cause ill health effects.

The body normally cools itself by sweating. But under some conditions, sweating just isn’t enough. Prolonged exposure to heat can cause cramping, heat exhaustion, heat stroke and even death. It is important to stay hydrated and seek cool temperature environments until the heat subsides.

Here are some tips to avoid heat-related illness during the summer:

Drink water. When the temperature rises, it is important to drink plenty of water. Drinks that contain caffeine, large amounts of sugar or alcohol should be avoided because they can cause you to become dehydrated.

Keep cool indoors. On hot days, prevent illness by keeping cool indoors. If your home is not air conditioned, try to spend the hottest hours of the day in a cool public place such as a library, movie theater, or store.

Dress for the heat. Wear lightweight, light-colored clothing. Light colors will reflect away some of the sun’s energy. It is also a good idea to wear hats or to use an umbrella. Always apply sunscreen to exposed skin.

Limit physical activity. Avoid excessive physical exertion in hot temperatures, especially in the middle of the day. If you must work outdoors, stay hydrated by drinking 2-4 glasses of water each hour and take frequent breaks in a cool place. Even a few hours in an air-conditioned environment reduces the danger of heat-related illness.

Do not keep children or pets in cars. Temperatures inside a car with windows up can reach over 150 degrees quickly, resulting in heat stroke and death.

Check on your neighbors. Although anyone can suffer heat-related illness, some people are at greater risk than others. People aged 65 or older are particularly susceptible to heat-related illnesses and complications that can result during periods of high temperatures and humidity.

Heat-Related Weather Terms:
Understanding heat-related weather terminology can help you and your family prepare for hot weather.

  • Heat Index: is a measure of how hot it feels when relative humidity is added to the air temperature.
  • Excessive Heat Outlooks: Issued when the potential exists for an excessive heat event in the next 3-7 days.
  • Excessive Heat Watches: Issued when conditions are favorable for an excessive heat in the next 24 to 72 hours.
  • Excessive Heat Warning/Advisories: Issued when an excessive heat is expected in the next 36 hours.

Signs & Symptoms of Heat-Related Illness:
Several heat-related health conditions can cause serious health problems. When temperatures are on the rise, watch for the following symptoms:

Dehydration— Dehydration is caused by the excessive loss of water and salts from the body due to illness or from prolonged exposure to heat. Severe dehydration can become a life-threatening condition if not treated.

Heat Cramps— Heat cramps are painful, involuntary muscle spasms that usually occur during heavy physical activity in hot environments. Muscles most often affected include those of your calves, arms, abdominal wall and back. If you are suffering from heat cramps, rest for several hours and drink clear juice or an electrolyte-containing sports drink.

Heat Exhaustion— Heat exhaustion occurs when the body loses too much water and salt from sweating during hot temperatures. The elderly, people who work outside and people with high blood pressure are most at risk of heat exhaustion. Continued exposure may lead to heat stroke, which is life-threatening.

Heat Stroke— Heat stroke is caused by prolonged exposure to high temperatures or by doing physical activity in hot weather. Sweating has usually stopped and your body temperature becomes too high; body temperatures can reach as high as 106 degrees in 15 minutes. Heat stroke is a life-threatening condition and you should seek immediate medical attention if you or someone you know is suffering from heat stroke.

Heat-Related Illness in Virginia

The Virginia Department of Health (VDH) receives data on visits to emergency departments and urgent care centers in Virginia for purposes of public health surveillance. These data are analyzed through a syndromic surveillance system, known as ESSENCE, to monitor the health of the community and identify emerging trends of public health concern. During the summer months (May to September), the Office of Epidemiology conducts surveillance for heat-related illness. For more data about the affects of heat-related illness in Virginia, please visit the Heat-Related Illness Surveillance page on the Office of Epidemiology Syndromic Surveillance program website.

For more information: