Eight glasses of water a day is too much – Wel.nl

Scientists say the oft-cited advice that you should drink eight glasses of water a day is probably too high.

Research suggests that two liters of fluids a day, or eight eight-ounce glasses, is often more than necessary for people who live in temperate climates.

The study authors estimate that many adults need not drink more than 1.5 to 1.8 liters per day, which is about six or seven cups. The new estimate takes into account that about half of our total daily water intake comes from food.

The study looked at about 5,600 people between the ages of 8 days and 96 years, from 23 countries. They had to drink a glass of water in which some of the water molecules contained a heavier form of hydrogen, an isotope called deuterium. The rate at which deuterium is removed revealed how quickly the body processes water.

The study showed that the processing speed is higher in hot and humid environments and at high altitudes, as well as in athletes, pregnant and lactating women, and people with heavy work. Some of these groups need more than two liters per day.