By JJ Menuet, Sports nutritionist
Why should we drink during an activity?
During an activity, athletes lose water for 3 reasons:
- Contracting the muscles creates heat (like an engine), which leads to water loss.
- During the sporting activity (especially if it's long and intense) we perspire, which means, of course, losing both water and salt (taste your sweat!) and the loss of salt during physical activity can result in a complex mechanism which accelerates water loss.
- Finally, if the ambient air is hot and the sun is beating down, the body temperature increases.
Dehydration is one of the main factors that lead to a loss of performance, and may even affect athletes' health: muscle injuries, cramps, tendinitis The heart beats faster, the breathing rate increases, the body temperature goes up, heat stroke become imminent, and they may become dizzy.
If the brain is insufficiently hydrated, its perceives sensations less well, makes bad tactical choices, lucidity is affected, movements are altered etc.
It is important to realise that losing 1% of one's water during activity brings about a loss of 10% of one's physical abilities, a loss of 2% of one's weight in water leads to a 20% decrease in one's physical capacities, and so on. An athlete weighing 70kg who loses 2kg in water loses 30% of his or her strength.
It is also essential to pay great attention to elderly and child athletes, because they are very sensitive to water loss.
How should you hydrate properly?
- 1 - For one hour before a physical or sporting activity lasting longer than an hour, it is advisable to consume 300ml of still water, especially in hot weather.
- 2 - Do not wait until you're thirsty to start drinking, because thirst is a message from the brain that you are insufficiently hydrated. So, drink at the start of the activity.
- 3 - If the activity lasts less than an hour, still water is enough (depending on the intensity).
- 4 - If the activity lasts longer than an hour and is intense, consume a sports drink.
- 5 - If it's hot and the cyclist sweats, the drink must also contain minerals (sweat contains minerals, especially salt).
- 6 - You have to imagine that at the exit of the stomach, there is a "computer" that controls the speed at which what we have drunk leaves the stomach in order to get to the muscles that are working. This "computer" processes several pieces of information such as the volume taken, the pH of the drink, the sugar concentration, the temperature of the drink, the fibre or fat content and the presence of bubbles (carbonated or "fizzy" drinks).
- 7 - Here are a few things you have to do to ensure optimum hydration:
- * drink often in small amounts (no more than 3 mouthfuls every 15 minutes, for example);
- * do not drink ice cold water during or after the activity (this can also trigger digestive problems);
- * do not eat too much fibre (dried fruit);
- * avoid fat;
- * avoid drinking fizzy drinks, since this is not nutritionally justified during activity (after the activity, however, I advise drinking a recovery drink and 250ml of a salty, bicarbonate drink, especially cyclists who have perspired a lot);
- * the pH of the drink should be neutral (around 7), and especially not acidic;
- * minerals (especially salt, at the appropriate amount, dissolved in the drink, but not in the form of tablets) speed up the rate at which the stomach evacuates its content.
- 8 - Drink after the activity to achieve the best possible recovery.
- 9 - Something to note: the last time you pass water at the end of the day, your urine should be clear, "like water"; otherwise you need to drink some more.
- 10 - In the evening, put a bottle of water within reach so you can drink a few mouthfuls if you wake up during the night.