Anyone can experience HRI when the body's temperature control system is overloaded. The body usually cools itself by sweating, but under some conditions sweating just isn't enough.
Body temperature can rise rapidly, which can damage the brain or other vital organs.
Several factors can negatively affect the body's ability to cool itself during extremely hot conditions or put a person at risk for being susceptible to HRI, such as
• High humidity
• Sunburn
• Fever
• Respiratory illness
• Dehydration
• Heart disease
• Mental illness
• Obesity
• Poor circulation
• Drugs or medications*
• Alcohol
• Age
* Those taking medications for depression, insomnia, or poor circulation may be especially affected by extreme heat.