Why hydrate yourself during physical effort.
60% of the body is composed of water. Water is therefore essential for the cells to function. It is involved in many of the chemical reactions that fulfil the demands of physical exercise. Water also allows the nutrients, which the body uses to adapt to physical exercise, to be transferred between the cells.
Water is used in stabilising the temperature of the body and prevents overheating. Indeed, during a triathlon, only 20 to 25% of the energy produced by the muscles is used to drive the body's movements; the remaining 75 to 80% produces heat. If the body does nothing to eliminate this heat, it accumulates and the body temperature increases to the point where it becomes damaging to the performance and health of the athlete. The body must therefore eliminate the excess heat. It achieves this by perspiring. Sweat is composed of water and minerals (mainly sodium).
Water is also used to eliminate the waste produced by physical exercise, either in the urine or the perspiration.
All these water losses can cause significant dehydration, which will be damaging to performance. It is therefore necessary to compensate for these losses with the right level of water intake.