University of Aberdeen scientists recently collaborated with other researchers to determine how much water people really need to drink. According to the media reports, they tested 5,604 people aged eight days to 96 years old from 23 different countries.
According to the survey findings, which were published in Science, people only need 1.5 to 1.8 litres of water per day, which is less than the two litres typically recommended.
People took part in the study by drinking a glass of water with some hydrogen molecules replaced by a stable isotope of deuterium, which occurs naturally in the human body and is entirely harmless. The rate of extra deuterium elimination indicates how quickly the water in the body turns over. People who have a higher water turnover need to drink more water.
According to the report, people who live in hot and humid environments and at high altitudes, as well as athletes and pregnant and breastfeeding women, require more water because their water turnover is higher. According to the study, men aged 20-35 drank an average of 4.2 litres per day, while women aged 20-40 drank 3.3 litres. Prof John Speakman of the University of Aberdeen told BBC Radio Scotland's Good Morning Scotland that the original estimate of two litres per day was based on a minor calculation error.
"The water we'd need to drink is the difference between the total amount of water we'd need to consume and the amount we get from food. They calculated the amount of food by asking people how much they ate. Because people under-report how much they eat, there is an underestimation, and thus you overestimate the amount of water required," he explained. Speakman also clarified that water turnover does not equal the need for drinking water.
"Even if a male in his twenties has a water turnover of 4.2 litres per day, he does not need to drink 4.2 litres of water every day," he said. Surface water exchange and water produced by metabolism account for about 15% of this value. The actual daily water requirement is approximately 3.6 litres. Because most foods contain water, eating provides significant water."
