The study of the effect of coffee, and caffeine in particular, on fluid balance can be split into two distinct areas: caffeine intake in the general population and caffeine intake specifically during exercise
Water makes up about sixty percent of body weight. As every system in the body depends on the availability of fluids, even mild dehydration can impair bodily functions and performance.
There are widespread guidelines on the amount and types of fluid we should be drinking in order to remain well hydrated. We’re often told to drink 2 litres of fluids a day and limit our consumption of caffeinated beverages, including coffee