CDC’s Tracking Network in Action

Woman wiping sweaty forehead and drinking bottled water

Extremely hot weather can make you sick. Stay cool and hydrated to protect yourself. The Tracking Network provides data and tools that you can use to see how extreme heat may affect your health.

CDC's Environmental Public Health Tracking Network (Tracking Network) is a dynamic surveillance system that provides information and data about environmental hazards and the health problems that may be related to them. It presents what we know about where environmental hazards exist, where exposures happen, and how targeted action can protect health, reduce illness, and save lives. The Tracking Network is a unique resource that brings together environmental and health information that cannot be found, or is hard to find, anywhere else.

Extreme Heat and Your Health

Extreme heat events, or heat waves, are one of the leading causes of weather-related deaths in the United States. When temperatures rise in the summer, extremely hot weather can cause sickness or even death. Heat stress is heat-related illness caused by your body's inability to cool down properly. The body normally cools itself by sweating. But under some conditions, sweating just isn't enough. In such cases, a person's body temperature rises rapidly. Very high body temperatures may damage the brain or other vital organs.

Collage of heat images - dried mud, outdoor thermometer showing 100 degrees, boy drinking water

Extremely hot weather can make you sick. Stay cool and hydrated to protect yourself.

Tracking Heat Stress Illnesses

Tracking heat stress illness hospitalizations is important to CDC. The Tracking Network contains data on heat-related deaths and illnesses from 27 states and provides information to help you protect yourself from heat-related deaths or illnesses. You can use the Tracking Network to see if heat-related deaths and illnesses are rising or declining in your state or county. Also, you can read the recently released MMWR surveillance summary which highlights trends over time using ten years of the Tracking Network's heat stress hospitalizations data.

Understanding a preventable illness such as heat stress can help public health professionals protect people by

finding patterns of risk,
planning public health programs and activities,
preparing for and responding to emergencies, and
deciding how well the actions worked.

Highlights from the MMWR Surveillance Summary

Between 2001 and 2010, the 20 Tracking Program grantee states included in this report had
- about 28,000 Heat Stress Illness (HSI) hospitalizations.
- an overall 2%-5% increase in the rate of HSI hospitalizations as compared to 2001.
- a relatively strong link between the number of HSI hospitalizations and the average monthly high temperature/heat index.
Most HSI hospitalizations involve males and persons aged 65 years and older.
The highest rates of hospitalizations were in the Midwest and the South.

Prevent Heat Stress Illness

Heat-related illnesses or death are preventable if you follow a few simple steps.

Stay in an air-conditioned area during the hottest hours of the day. If you don't have air conditioning in your home, go to a public place such as a shopping mall or a library to stay cool. Cooling stations and senior centers are also available in many large cities for people of all ages.
Wear light, loose-fitting clothing.
Drink water often. Don't wait until you are thirsty.
Avoid unnecessary hard work or activities if you are outside or in a building without air-conditioning.
Avoid unnecessary sun exposure. When in the sun, wear a hat, preferably with a wide brim.

Air conditioning is the strongest protective factor against heat-related illness. Exposure to air conditioning for even a few hours a day will reduce the risk for heat-related illness.

Tracking in Action

The Tracking Network is used across the country to help states and cities prepare for summer and periods of extreme heat and to prevent illness.

See how Missouri's Tracking Network is used to map cooling centers for the public
Read about how the California Tracking Network and the city of San Jose work to justify cooling centers
New York City's Tracking Network is helping identify New Yorkers most at risk from extreme heat
Read about Minnesota Tracking Network's efforts to better track heat and related health problems