Extreme heat events: Health risks and who is at risk of extreme heat events

On this page

• Health risks of extreme heat events
• At-risk groups for extreme heat events

Health risks of extreme heat events

Your body produces heat, especially during physical activity. Hot air, sun rays and hot surfaces also heat your body. This heat is lost by contact with cool air and by sweat production, which cools your body as it evaporates.
Weather conditions play a big role in how your body regulates its temperature. For example, if it's windy, sweat evaporates faster, which helps to cool you. But high humidity slows down this process, contributing to increased body temperature.

Heat illnesses can affect you quickly, and can lead to long-term health problems and even death. They are mainly caused by being over-exposed to extreme heat especially if you are doing too much for your age and physical condition. Heat illnesses include:

• heat rash
• heat stroke
• heat fainting
• heat exhaustion
• heat cramps (muscle cramps)
• heat edema (swelling of hands, feet, and ankles)

At-risk groups for extreme heat events

While extreme heat can put everyone at risk from heat illnesses, health risks are greatest for:

• older adults
• low-income earners
• infants and young children
• people who work in the heat
• people who exercise in the heat
• people experiencing homelessness
• people with chronic illnesses (like breathing problems, mental illness and heart problems)

If you are taking medication or have a health condition, ask your health care provider if either:

• increases your health risk in the heat
• makes your skin more sensitive to ultraviolet (UV) rays

Heat illnesses are preventable. During extreme heat, the most important thing is to keep cool and hydrated.