If You Drink 8 Glasses of Water a Day... You Just End Up Going to the Bathroom More Often

Misinterpretation of 77-Year-Old Recommendation... No Practical Benefits
Water from Food and Other Beverages Should Also Be Included in Measurement
Living in Hot Climates or Being More Active Requires Increased Water Intake

[Asia Economy Reporter Kim Sung-wook] A study has revealed that the belief that one must drink 8 glasses of water a day is incorrect. On the 6th (local time), The Washington Post (WP) introduced research published in the journal Science that found the recommended daily water intake of about 2 liters to be unnecessary. According to this study, there is no substantial benefit for healthy adults to drink 8 glasses of water a day, and drinking less is not risky. Hermann Poncher, a professor of evolutionary anthropology at Duke University and co-author of the study, said, "If you drink 8 cups of water a day, you will spend much more time in the bathroom."

The study explains that the reason the '8 cups of water per day' recommendation is partially wrong is because people do not consider the hydration they get from food and beverages like coffee and tea. This belief was first recommended in 1945 by the Food and Nutrition Board of the National Research Council (NRC). Although the total daily water intake including all food and beverages was mentioned there, it was misinterpreted by people. In fact, another study involving 883 elderly people found no evidence of dehydration in 227 individuals who routinely drank 6 or fewer glasses of water daily.

The researchers studied how much water people really need. They analyzed data from 5,600 individuals aged from 8 days old to 96 years old across 26 countries. The study participants included various groups such as farm workers, athletes and non-athletes, office workers in Europe and the United States who sit for work, and people from agricultural and hunter-gatherer societies in South America and Africa.

The participants were measured using the "doubly labeled water" method, which uses water tagged with tracers to track the body's carbon dioxide production process. Through this method, the researchers assessed the body's water turnover rate to evaluate participants' water intake and loss. The results showed that a person's daily water turnover rate is largely influenced by the size and level of body fat; the less body fat, the more water is needed. In other words, men generally require more water than women because they tend to have larger bodies and less body fat.

They also discovered that water needs change throughout a lifetime. This is because the amount of water required varies depending on metabolic rate and calorie expenditure. Generally, water needs peak between ages 20 and 50, then decrease as metabolism slows down. Professor Poncher added, "All cellular functions are based on water."

The researchers also noted that climate and sedentary lifestyle affect water requirements. People living in hot climates or those who move more need more water. Professor Poncher said, "People from relatively poorer countries tend to need more water because they are more likely to work outdoors every day."