Triathlon is a demanding sport where every detail matters, i.e. technique, experience, mental management, equipment and, of course, nutritional strategy. Hydration is one of the keys to completing a triathlon. Any uncompensated loss of water will be damaging to the triathlete's performance level, whatever their physical level of ability.
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.
Triathlon can cause dehydration because of the level of perspiration. The body may lose over one and a half litres through perspiration each hour, and sometimes up to three litres an hour. The risk of dehydration is real, regardless of the atmospheric conditions and increases in hot conditions and particularly in humid heat. Dehydration is the main source of injury and underperformance. It is estimated that a 1% decrease in body weight will cause a 10% drop in physical ability and a 2% decrease in body weight will cause a 20% drop in physical ability.
It is essential that the body regularly takes on water. Do not wait to feel thirsty as this feeling is not a good indicator. The feeling of thirst emerges relatively late, when your body weight has already decreased by 1%. Furthermore, it takes time to absorb water and transfer it to the bloodstream.
- Drink the day before the event right up until you go to bed in order to stay hydrated.
- During the last three hours before the start, take a pre-race drink to maintain your hydration, particularly in hot conditions.
- Do not wait to feel thirsty before drinking. Drink regularly (every 10 – 15 minutes) in small quantities (one or two mouthfuls).
- If the triathlon is going to take less than one hour, water alone will be sufficient (depending on the intensity).
- If the triathlon is going to take more than one hour, take an ISO type isotonic drink suited to the level of physical exercise.
- If the triathlon is going to last more than three hours, take an ISO+ type isotonic drink that is rich in minerals and antioxidants
- Drink one mouthful of water during each transition.
- Keep the bottle of pure water to splash over your body and rinse your mouth.
- During and after the triathlon, do not take ice-cold drinks as this can create digestive problems.
- Drink plenty of fluids after the triathlon to optimise your recovery.
- After the triathlon, keep a bottle of water close at hand so that you can continue to hydrate regularly.
Diététicienne - Nutritionniste, passionnée de raid multisport et d’aviron