a condition caused by excessive loss of salt and water, usually resulting from overexertion in a hot environment, and characterized by peripheral vascular collapse, dizziness, nausea, low body temperature, clammy skin, etc.
See heat exhaustion in American Heritage Dictionary 4
A condition caused by exposure to heat, resulting in the depletion of body fluids and causing weakness, dizziness, nausea, and often collapse. The condition can be alleviated by rest and the administration of fluids and electrolytes to compensate for those lost through excessive sweating. Also called heat prostration.