WARNING: Extreme Heat Advisory Issued

If you have air conditioning, you may want to turn it up and stay indoors.

The National Weather Service has issued an excessive heat advisory, effective Thursday afternoon and lasting until at least late Friday, for most of Massachusetts and parts of New Hampshire and Rhode Island.

Temperatures are expected to reach up to a scorching 100 degrees, especially between noon and 8 p.m. Residents are advised to stay indoors as much as possible during those times, seek shelter in shaded areas when outdoors, wear loose fitting clothing and drink a lot of water to stay hydrated.

Be Safe

This kind of heat is dangerous. Heat exhaustion occurs when someone is too active in hot temperatures.

Heat stroke is even more severe and can be life-threatening. Children, the elderly and people with illness will be especially vulnerable to heat stroke.

Lawrence General Hospital's Web site details both heat exhaustion and heat stroke.

Symptoms of heat exhaustion and heat stroke include:

• Body temperature over 100 degrees
• Rapid pulse.
• Sweating.
• Low blood pressure.
• Nausea
• Dizziness
• Confusion

And there are several factors that increase risk for heat stroke.

• Activity involving long periods of outdoor activity in hot weather.
• Age -- the elderly and children are especially at risk.
• Not ingesting enough fluid.
• Ingesting too much salt.
• Drugs interfering that interfere with the way your body handles hot weather, including alcohol, cocaine and several kinds of prescription and over-the-counter medications.

If you think you or a loved one are suffering from heat stroke, call 911 immediately.