In some cases victims, especially the elderly, should be hospitalized. Heat exhaustion is more likely after a few days of a heat wave than when one is just beginning. The best defense is to take it easy and drink plenty of water. Don't take salt tablets without consulting a physician. In some cases extreme heat can upset the body's thermostat, causing body temperature to rise to 105 degrees or higher.
Symptoms are lethargy, confusion and unconsciousness.
Even a suspicion that someone might be suffering from heatstroke requires immediate medical aid. Heatstroke can kill. If you know the relative humidity and the dry air temperature, then you can use the following equation to calculate the heat index. If you know the relative humidity and the dry air temperature, then you can use the following equation to calculate the summer simmer index.