What causes heat-related illness?
Normally, the body is efficient at keeping itself cool — perspiring and letting heat escape through the skin. The evaporation of sweat cools the skin. But if the body cannot cool itself well enough, people can become ill.

Indeed, when temperatures climb over 90 degrees Fahrenheit, people become susceptible to heat-related illness — especially young children and the elderly. Exposure can cause serious injury or, in rare cases, death, if left unattended.

Know the terms
• Heat wave: More than 48 hours of high heat (90 degrees F or higher) and high humidity (80 percent relative humidity or higher) are expected.
• Heat index: A number in degrees Fahrenheit that tells how hot it really feels with the heat and humidity. Exposure to full sunshine can increase the heat index by 15 degrees F.
• Heat cramps: Heat cramps are muscular pains and spasms due to heavy exertion. They usually involve the abdominal muscles or the legs. It is thought that the loss of water and salt from heavy sweating causes cramps.
• Heat exhaustion: Heat exhaustion is less dangerous than heat stroke. It typically occurs when people exercise heavily or work in a warm, humid place where body fluids are lost through heavy sweating. Fluid loss causes blood flow to decrease in the vital organs, resulting in a form of shock. With heat exhaustion, sweat does not evaporate as it should, possibly because of high humidity or too many layers of clothing. As a result, the body is not cooled properly.
• Heat stroke: Also known as sunstroke, heat stroke is life-threatening. The victim’s temperature control system, which produces sweating to cool the body, stops working. The body temperature can rise so high that brain damage and death may result if the body is not cooled quickly.

Stay cool
• Dress for the heat. Wear a hat, and breathable, moisture-wicking, light-colored clothing. Light colors will reflect away some of the sun’s energy.
• Stay hydrated. Carry water or juice with you, and remember to intake fluids, even if you do not feel thirsty. Water is the safest liquid to drink during heat emergencies.
• Eat small meals, and eat more frequently.
• Slow down. If you must do strenuous activity, do it during the coolest parts of the day, generally before 7:00 a.m. and after 7:00 p.m.

Avoid …
• Drinks with alcohol or caffeine in them. They can make you feel good briefly, but make the heat’s effects on your body worse. This is especially true about beer, which dehydrates the body.
• Foods that are high in protein, which increase metabolic heat.
• Salt tablets, unless directed to do so by a physician.

Take special care
People at higher risk for heat-related illness should take extra care to avoid a problem by taking breaks from activity, seeking a cool place, and drinking at least eight glasses of water a day or more if exercising or working strenuously. This includes:
• People working or exercise outdoors
• The elderly and young children
• Those with circulation or breathing problems
• People who have ingested alcohol
• People taking certain medications or who have medical conditions that may cause poor blood circulation or reduced ability to tolerate heat. Discuss these concerns with a physician.