MISSISSIPPI STATE -- To call Mississippi summers hot is accurate, but they can also be dangerous as heat and humidity combine to create a deadly threat of heatstroke.

Mississippians saw record-breaking temperatures in July, and while August started cooler, more heat is in store. According to the National Oceanic and Atmospheric Administration, Jackson saw five days in July where temperatures reached 100 degree or more, setting one new record and tying another.

Linda Patterson, health education specialist at Mississippi State University's Extension Service, said heat can be simply unpleasant, or it can lead to life-threatening heat stroke.

"The risk of heat illness is present when the heat index is 100 degrees or more," Patterson said. "When the heat index is this high, prolonged exposure or physical activity can lead to several illnesses such as heat stroke, heat cramps or heat exhaustion."

The heat index combines the effects of heat and humidity, and is the opposite of wind chill. Warm temperatures feel even warmer when there is high humidity.

Heat illnesses occur when the heat overcomes the body's ability to regulate internal body temperature at a safe level. Signs of heat illness include nausea, weakness, fainting and pale, clammy skin. Often, the skin turns red and dry, providing a warning signal of heat illness.

"Prompt action can prevent the most serious heat illness heat stroke which is fatal 50 percent of the time," Patterson said.

According to NOAA, there are four kinds of heat-related illnesses. Sunburn is redness and pain in the skin, with possible swelling, blisters, fever and headache. Heat cramps are described as heavy sweating and painful spasms, usually in the legs or abdominal muscles.

Heat exhaustion is the stage before heat stroke where sufferers become weak and sweat heavily. The skin is cold, pale and clammy, the pulse becomes weak and rapid, and the person faints or vomits. Heat stroke can cause a person to lose consciousness, and is defined as a body temperature of 106 or higher along with hot, dry skin and a rapid, strong pulse.

The first defense against heat illness is prevention. Avoid heavy physical exertion in the middle of the day. Wear a broad- brimmed hat and light-colored cotton clothing that allows air to circulate around the body. Drink at least eight ounces of non- alcoholic, non-caffeinated drinks each hour. Keep windows open for ventilation in cars or houses without air conditioning.

If these tips are ignored or the heat is too intense and a heat illness occurs, first aid is required.

"Stop the activity, improve air circulation with a fan or air conditioner, and sponge the body with cool water," Patterson said. "Give a conscious person sips of cool, diluted fruit juice, sports drink or water. Heat illness is an emergency situation and requires medical care."