Watch for these Signs Heat exhaustion is the body's response to excessive loss of water and salt contained in sweat. Persons most prone to heat exhaustion are the elderly, people with high blood pressure and those working or exercising in a hot environment. This is true in all seasons, but particularly in the summer months. There are many factors that put an outdoor worker at risk for dehydration. Examples of these are extreme temperatures, wind, sun and physical exertion.
Some people prefer to drink sports drinks.
That's fine, but they are not really necessary. A normal diet provides minerals and salts necessary to replace losses due to exertion. Thirst is often considered a reliable signal that we need to drink. It is important for people who work outside to monitor their urine output. Dark and scant urine is a sign of dehydration.