Heat syncope is a fainting (syncope) episode or dizziness that usually occurs with prolonged standing or sudden rising from a sitting or lying position.
Heat stroke is the most serious heat-related illness. It occurs when the body becomes unable to control its temperature: the body's temperature rises rapidly,
Heat rash is a skin irritation caused by excessive sweating during hot, humid weather.
Heat exhaustion is the body's response to an excessive loss of the water and salt, usually through excessive sweating.
Heat cramps usually affect workers who sweat a lot during strenuous activity. This sweating depletes the body's salt and moisture levels.