Temperature

• Rising body temperature is the most common sign of heat distress. Initially, the body's temperature will only rise slightly, reaching 101 degrees. If the person is left in the hot environment, the body loses all ability to regulate itself and the temperature can shoot up to over 106 degrees. As the temperature rises, associated signs, such as confusion, delirium, seizures and coma, will present themselves.
  
  

Skin Changes

• Excessively sweaty skin is the first noticeable skin change. The body sweats heavily to try and facilitate cooling through evaporation. As the body loses its ability to sweat, skin becomes clammy, and is often pale. Eventually, the skin dries out, becoming red and hot to the touch. Each stage represents a different level of heat distress, starting at heat exhaustion and moving toward heat stroke.
  
  

Neurological Signs

• Neurological symptoms set in as the rising body temperature compromises brain function. Dizziness, headache, loss of muscle coordination and slight changes in mental status, such as giddiness or anxiety, are early symptoms. As the person becomes increasingly distressed, they will experience an increase in severity of the previous symptoms, as well as confusion and abnormal behavior, and in the late stages, seizures and coma.
  
  

Other Signs

• Nausea is one of the earliest signs of heat exhaustion, according to a 2007 study done by researchers at the University of Heidelberg in Germany. Vomiting eventually accompanies the nausea, complicating the heat disorder with dehydration. A rapid, but thready pulse of 120 to 200 beat per minute is common during moderate stages of heat distress. Occasionally, when heat distress results in multi-system organ failure, yellowing of the eyes and urine retention may be present.
  
  

Prevention

• Hydration is one of the easiest ways to prevent heat distress. Drink enough to replace the fluids lost through sweating. A mix of water and drinks with electrolytes, such as sports drinks, is ideal. Lightly colored, loose-fitting clothing allows the body to lose heat through the skin. Regular breaks in the shade are a necessity on days with high temperatures or humidity, especially if the activity being done is physically exhausting.