There is quite a difference. Heat exhaustion may come to those who are quite well, when exposed for a long time to very hot rooms. Stokers and men who feed furnaces are very liable to be brought down with heat exhaustion. But those who are brought down with sunstroke are sick, and often their resistance is so very low that they will go down under the effect of heat which the average person will not consider excessive. The victim falls into a state of prostration, and may die within an hour, the principal symptoms being those of heart failure, difficult breathing, and a comatose state.
Some writers describe fatal cases that occur almost instantaneously.
Victims fall as if shot down. The more common forms present pain in the forehead, dizziness, and a feeling of difficult breathing, with nausea and vomiting. In some cases there are diarrhea and frequent urination. If dyspepsia has helped the hot weather to bring on the condition, the breath will usually show it. There will be an alcoholic odor to the breath.