It occurs under conditions of high humidity and temperature. It blocks one of the major body defenses against heat illness the ability to perspire and evaporate moisture from the body surface. No one is immune. Anyone with heart or lung problems, diabetes, obesity, history of previous heat illness, cardiac arrhythmia, neurological problems including stroke, cystic fibrosis, late pregnancy, the very young or old person, and persons who are young, conditioned and over-confident. Cramping of the muscles in the arms and legs or abdominal muscles is an early sign of heat illness.
Heat cramps are helpful because they force a person to stop and rest.
Heat exhaustion or heat collapse is a result of a sudden drop in blood pressure. The skin will be clammy from perspiration. The person will feel weak and may experience fainting. The body temperature will be normal or slightly elevated. The symptoms are due to dehydration.