If you do not stay aware of the environmental conditions and your personal physiological status, you can progress to heat exhaustion, even if you are maintaining the above re-hydration water intake. This is because under certain conditions external fluid intake cannot keep up with the loss of fluid by the body. Here are some suggestions on how to be aware of and prevent heat exhaustion. Carry a container so you can measure daily water intake. If plain water is offensive, add some sport drink flavoring to make it more acceptable.
Exercise can cause a large amount of body fluid loss that is difficult to replace quickly.
Acclimation to a major change in weather takes one to two weeks. Monitor personal effects of aging, recent illness, fever, diarrhea, or vomiting. In extreme heat and exercise conditions, salt and electrolyte loss is a factor but not for the average person with a moderate exercise program. The American diet takes care of the loss. Fly safe and never pass up an opportunity to have a fresh glass of water.