Heat stroke is a life threatening condition that needs immediate medical attention. The body temperature rises to over 104 F causing an inability for the body to release heat. High fever resulting in coma can be the outcome. Climates with high humidity make matters worse. Heat stroke and sun stroke are the same thing. Extreme exposure to the sun causes this condition. Symptoms include rapid heart beat, lack of perspiration, headache, hallucinations and hot dry skin. On hot humid days avoid the outdoors but if you are outdoors make sure to drink lots of fluids. Avoid coffee and alcohol which lead to dehydration.

First of all let me say the previous answer(s) give great insight into the world of heat stroke, but I feel that I need to give the progression into heat stroke from heat cramps: According to the American Red Cross: "Heat cramps, heat exhaustion and heat stroke are conditions caused by overexposure to heat. Heat crams are the least severe but, if not care for, may be followed by heat exhaustion and heat stroke. Heat Cramps Heat cramps are painful spasms of skeletal muscles. Heat cramps usually affect the legs and the abdomen but they can occur in any voluntary muscle. The exact cause of heat cramps is not known, although it is believed to be a combination of loss of fuluid and salt from heavy sweating. Heat cramsp develop fairly rapidly and usually occur after heavy exercise or work in warm or even moderate temperatures. The victim's body temperature is usually normal and skin moist. However, heat cramps may also indicate that a person is in early stages of a more severe heat-related emergency. To care for heat cramps, have the victim rest comfortably in a cool place. Lightly stretch the muscle, then grasp it firmly and squeeze it. Provide coll water or a commercial sports drink that contains nutrients, such as carbohydrates, electrolytes and simple sugars, to replace those lost through heavy sweating. Usually, rest and fluids are all the body needs to recover. The victim should not take salt tablets or salt walter. Ingesting high concentrations of salt, whether in tablit or liquid form, can hasten the onset of heat-related illness. When the cramsp stop and no other signals of illness are present, the person can usually resume activity. The person should be watched carefully, however, for signals of developing heat-related illness. He or she should continue to rink plenty of fluids during and after activity. Heat Related Illness Heat-related illness, if not cared for promptly, can get progressively worse in a very short period of time. By recognizing the signals of the early stages of heat-related illness and responding appropriately, you may be able to prevent the condition from becoming life threatening. Early Stages of Heat-Related Illness Heat exhaustion is the early stage and the most common form of heat-related illness. It typically occurs after long priods of strenuous exercies or work in a hot environment. Although heat exhaustion is commonly associated with athletes, it also affects firefighters, construction workers, factory workers and others who are very active and wear heavy clothing in a hot, humid environment. However, strenuous activity is not a prerequisite for heat exhaustion-it can happen when a person is relazing or standing still in the heat. Heat exhaustion is an early indication that the body's temperature-regulating mechanism is becoming overtaxed. It is not always preceded by heat cramps. Over time, the victim loses fluid through sweating, which decreases the blood volume. Blood flow to the skin increases, reducing blood flow to the vital organs. The circulatory system is affeceted, and the person goes into a form of shock. The signals of heat exhaustion include-- * cool, moist, pale, ashen or flushed skin. * headache, nausea, dizziness. * weakness, exhaustion. * Heavy sweating. Heat exhaustion in its early stage can usually be reversed with prompt care. Late Stages of Heat-Related Illness Heat stroke is the least common and most severe heat-related emergency. Heat stroke most offten occurs when people ignore the signals of heat exhaustion or do not act quickly enough to give care. Heat store develops when the body systems are so overtaxed by heat that they begin to stop functioning. Swating often stops because body fluid levels are low. When sweating stps, the body coannot cool itself effectively through evaporation. Body temperature rises quickly, soon reaching a level at which the brain and other vital organs, such as the hear, and kidneys, begin to fail. If the obody is not cooled, convulsions, coma and death will result Heat stroke is a serious medical emergency. You must recognize the signals of heat stroke and give care immediately. The signals of heat stroke include-- * Red, hot, dry skin. * Changes in level of consciousness * Vomiting. Care for Heat-Related Illness Time is of the essence when caring for heat-related illness. The longer a heat-related illness goes untreated, the worse the condition becomes. Specific steps for care depend on whether you find the victim in the early or late stages of a heat-related illness. Care in Early Stages If you recognize heat-related illness inits early stages, you can usually reverse it. Follow these general steps: * Cool the body. * Give fluids if the victim is conscious. * Take steps to minimize shock. Remove the victim from the hot environment and give him or her cool water to drink. Moving the victim out of the sun or away from the heatallows the body's own temperature-regulating mehanisms to recover, cooling the body more quickly. Loosen any tight clothing and remove clothing soaked with perspiration. Apply cool, wet cloths, such as towels or sheets, to the wrists, ankles, armpits, groin and back of the neck, and fan the victim to increaseevaporation. If the victim is conscious, slowly drinking cool water will help replenish the vital fluids lost through sweating. The victim is likely to be nauseated. Water is less likely than other fluids to cause vomiting and is more quickly absorbed into the body from the stomach. Do not let the victim drink too quickly. Let the victim rest in a comfortable position, and watch carefully for changes in his or her condition. A victim of heat-related illness should not resume normal activities the same day. Care in Late Stages If you observe changes in the victim's level of consciousness, call 9-1-1 or the local emergency number and cool the body quickly by any means available. Soak towels or sheet in cool wter and apply them to the victim's body. Use a water hose, if one is available, to cool the victim. If you have ice or cold packs, wrapthem in a cloth and place them on each of the victim's wrists and ankles, on the groin, in each armpit and on the neck to cool the large blood vessels. A person in heat stroke may experience respiratory or cardiac arrest. be prepared to perform rescue breathing or CPR, if needed." For information on Heat Related Illness contact your local American Red Cross or visit www.redcross.org