Hydration in athletes - World Water Day 2025
Article by Joana Resende, Nutritionist of the UPFit Program.
March 22nd is World Water Day. This date was established by the United Nations (UN) in 1993, with the purpose of promoting public discussion on the problem of water resources.
We and the Water
Our body is made up of around 60-70% water, which plays an important role in transporting nutrients, as well as in several metabolic reactions in the body. Did you know that maintaining adequate hydration before, during and after exercise is essential in the daily lives of athletes?
Ensuring adequate water intake is important for maintaining adequate body temperature, organ function, and good physical and cognitive performance. During training, the goal is to prevent dehydration. In this sense, the weight lost during training should be <2% of total body weight.
The consequences of dehydration
Insufficient water intake poses health risks, including:
- Increased occurrence of cramps and muscle fatigue.
- Increased risk of injury.
- Cognitive changes and changes in motor response.
Pre-competition: Recommendations
The recommendation is between 5-7 ml of water per kilogram of body weight. Taking an athlete weighing 70 kg as a reference, he or she should drink between 350 and 500 ml of water 4 hours before (lunch).
If you do not produce urine or if it is darker in color, it is still recommended to drink 3 to 5 ml of water per kilogram of body weight, which translates into 200 to 350 ml of water 2 hours before the competition.
In the pre-competition context, it is possible to identify some signs of dehydration, such as the color of urine and body sweat.
During the competition
During the competition, between 400 and 800 ml of water should be consumed per hour. In addition to water, sports drinks such as Gatorade, Powerade or isotonic drinks may be included to ensure a supply of carbohydrates during the competition and to replace some mineral salts that are lost through perspiration.
Post-competition
After exercise, it is important to replace what was spent/lost, thinking about recovery and the next competitive event.. The recommendation is 1,5ml of water per weight lost, which means that if the weight loss between the beginning and the end of the exercise is half a kg (500g), the intake will be 750ml. In many sports contexts, this assessment may not be a reality and in these cases, the most important message to convey is the importance of maintaining good hydration even after exercise.
