Swimming is the most complete sport: it develops the muscles and keeps the joints flexible with Lifeguard Class. It has the added advantage that the chance of injuries is almost zero.
The amount of energy you use while swimming can vary greatly. It depends on the distance you cover, the technique you use, and its efficiency, and on the intensity of your exercise, water temperature, and your weight.
At a leisurely pace (about 2 km/h), the energy consumption is around 400 kcal/h.
With a somewhat more intensive training (about 3 km/h), a swimmer consumes between 600 and 700 kcal/hour, which for someone who trains 4 hours a day, comes down to a daily energy requirement of about 5000 kilocalories.
The recommended distribution over the various nutrients is 60% carbohydrates, 15% proteins and 25% fats.
The proportion of fats can be increased during endurance training or when swimming in natural waters (water temperature <24°C)
In short distance swimmers (50m and 100m) who need more muscle power, the protein percentage can be increased from 15 to 20-25%.
The idea that you don’t sweat while swimming should not hide the fact that a high-level swimmer loses about 120-140 ml of fluid/km.
In the water, even with great exertion, the body temperature rises only slightly, which has the converse effect that the swimmer often feels the need to hydrate less than other athletes.
That while dehydration, even to a slight degree, has major consequences: less good recovery, increased injury risk, less muscle efficiency and therefore poorer performance.
Thirst is not a good indicator because that feeling only occurs late, when dehydration has already started, so you should drink before you get thirsty.
What should you drink?
For sessions of less than an hour, water is sufficient. After that, a sports drink is recommended that maintains muscle reserves and glycemia (blood sugar level).