Which heat injury results from excessive water and salt depletion with profuse sweating, headache, weakness, pallor, nausea, vomiting, mild dyspnea and palpitations, and may involve loss of consciousness?

• A. Heat cramps
• B. Heat stroke
• C. Heat exhaustion
• D. Heat syncope

Answer: (C)

Excessive sweating with significant fluid and electrolyte loss reduces circulating blood volume and impairs heat dissipation, leading to the symptoms of heat exhaustion: weakness, pallor, headache, nausea, vomiting, and sometimes mild shortness of breath and palpitations, with the potential for fainting if the dehydration is severe. This pattern specifically reflects dehydration-driven heat illness without the extreme hyperthermia or central nervous system dysfunction seen in heat stroke, and without the cramps that are focused on muscle groups in heat cramps or the sudden fainting from vasodilation seen in heat syncope. In heat exhaustion, you would expect these systemic signs alongside dehydration, and progression to heat stroke would require urgent cooling and more aggressive management.