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 generally thought that the loss of water and salt from heavy sweating causes the 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 blook 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. Signals include cool, moist, pale or flushed skin, heavy sweating, headache, nausea or vomiting, dizziness and exhaustion. Body temperatures will be normal. Heatstroke is life threatening.