The National Weather Service developed the heat index to help people identify days when the risk for a heat illness is higher than normal. During a heat wave, the heat index is excessive for many days in a row. Everyone has an increased risk for a heat-related illness during a heat wave.
A heat-related illness can be more serious for:
- Older adults, who may not notice excessive heat, do not sweat as effectively, or do not feel thirsty.
- Infants and children, who can't transfer heat very well.
- People with chronic medical conditions, such as heart disease, mental illness, or being overweight..
- People with developmental problems.
Other things that affect a person's risk for a heat-related illness during a heat wave include:
- Living in cities, because heat is trapped by tall buildings and air pollutants.
- Living alone.
- Working outdoors.
- Exercising outside.
- Not having cooling devices, such as fans or air-conditioning.
Current as of: July 21, 2022
Author: Healthwise Staff
William H. Blahd Jr. MD, FACEP - Emergency Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine