Having enough water in the body is critical to surviving extreme heat, but elderly people have several things working against them when it comes to hydration. They start out with less water, relative to body weight, than younger people, so their stores can be quickly consumed. Adding to the problem, their awareness of thirst is diminished, so they won t drink as soon as they should, especially if they have difficulty moving about or swallowing. In many elderly people, Stoukides says, the kidneys are no longer efficient at conserving water. Many also take medications that interfere with fluid metabolism.
Any liquid is fine, even coffee.
Just keep consuming fluids. One of the first signs of heat illness is confusion, and that adds to the danger. Elderly people can quickly become dehydrated and then confused, unaware that a medical emergency looms. At greatest risk is an elderly person home alone in a hot city. Many close their windows at night out of fear.