Experts point out that the right amount of water is determined by individual and climatic factors. Pregnant women, athletes and workers, for example, often need more fluid.
A group of researchers deny that the human being needs to drink eight glasses of water a day (approximately two liters) in a standard way, and ensures that the daily consumption of liquid is determined by several individual factors of each person, affirms a study released by the Science magazine.
The scientists studied more than 5,600 people, of different ages, genders and parts of the world, who claimed to drink from 1 to 10 liters of water per day.
The participants received 100 milliliters of “double labeled water” with deuterium, an isotope of hydrogen, and Oxygen-18, an isotope of oxygen, a drinkable that is safe in small amounts.
“If you measure the rate at which a person eliminates those stable isotopes through urine over the course of a week, the hydrogen isotope can tell us how much water they are replacing, and the oxygen isotope elimination can tell us how many calories they are burning. ”said Dale Schoeller, co-author of the study.
There is no “one size fits all” amount of water a day
After reviewing their results, the scientists concluded that the ideal daily water intake varies by age, gender, level of physical activity, and climate.
“The current study clearly indicates that there is no single amount for drinking water guidelines, and the common suggestion that we should drink eight 8-ounce glasses of water a day (~2 liters) It is not supported by objective evidence.the researchers said.
Under similar conditions, a 20-year-old male athlete, weighing 70 kg and living at sea level with 50% humidity and a temperature of 10°C will have a water turnover of about 3.2 liters per day.
A non-athletic woman of the same age and under the same conditions will have a water turnover of about 2.7 liters per day, that is, the ladies normally needed a pint less of water than the men.
movement and weather
Still, the researchers stressed that the amount of energy used per day, as well as body weight, increased humidity or temperature, pregnant women, and physical or athletic work, are all factors to be taken into account. time to hydrate.
Those who drank 10 liters of water a day were generally men exposed to a hot climate, actively working with their bodies, athletes, or foragers from Amazonian Ecuador.
Meanwhile, people who lead a sedentary lifestyle in temperature-controlled indoor environments needed less water turnover than people who work physically.
“The improvement of the guidelines is increasingly important due to the explosive growth of the population and the climate change that the world is currently facing, which will affect the availability of water for human consumption,” the researchers conclude.