Heat exhaustion is a milder form of heat-related illness that can develop after several days of exposure to high temperatures and inadequate or unbalanced replacement of fluids. Those most prone to heat exhaustion are elderly people, people with high blood pressure and people working or exercising in a hot environment.

Warning signs of heat exhaustion include the following:

• Heavy sweating
• Paleness
• Muscle cramps
• Tiredness
• Weakness
• Dizziness
• Headache
• Nausea or vomiting
• Fainting

The skin may be cool and moist. The victim's pulse rate will be fast and weak, and breathing will be fast and shallow. If heat exhaustion is untreated, it may progress to heat stroke. Seek medical attention immediately if symptoms are severe or the victim has heart problems or high blood pressure.

Otherwise, help the victim to cool off and seek medical attention if symptoms worsen or last longer than one hour.

Cooling measures that may be effective include the following:

• Cool, nonalcoholic beverages, as directed by your physician
• Rest
• Cool shower, bath or sponge bath
• An air-conditioned environment
• Lightweight clothing