This is confirmed by the "Comparative Study of Different Moisturizing procedures, prepared by the Department of Exercise Physiology at the Catholic University San Antonio de Murcia (UCAM), which was aimed at evaluating the capability of properly hydrated in the heat and high humidity, according to various strategies based on eating many kinds of drinks with different flavors.

Research indicates that fluid intake is 50% higher when there is diversity of beverages, like water, soft drinks, juices, and therefore reduces the loss of body weight, indicating a state of dehydration. Furthermore, when the drinks taste good consumption increases by 32%.
Prolonged physical activity, especially in hot and humid conditions, body temperature rises and sweat, so they are lost fluids and electrolytes (minerals). This decreases the resistance. In these cases, we must drink before, during and after physical exertion.

The elderly are also a population at risk, because with age, temperature-regulating mechanism is impaired and the sensation of thirst decreases, so it costs them drink.

Therefore, you need to drink before you are thirsty, and when it appears that this signal is lost around 1% of body fluid so there is a degree of dehydration.