Scientists Confirm Eight Glasses Of Water A Day May Be Too Much

Eight glasses of water a day might not be the best recommendation after all, according to scientists.

To determine how much water people truly need to be drinking, researchers from the University of Aberdeen worked with other experts to interview 5,604 individuals from 23 different nations, ranging in age from eight days old to 96.

Participants in the study drank water that had some hydrogen molecules substituted with the stable isotope of the element deuterium. This allowed researchers to determine how quickly the body's water circulates.

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People with a high turnover rate, such as those who reside in hotter climates and pregnant and nursing mothers, frequently consume and need more water.

Men aged 20 to 35 years old had an average daily turnover of 4.2 liters, which gradually decreased with age.

Women between the ages of 20 and 40 had 3.3 liters of blood turnover, which likewise decreased with age.

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Eight glasses of water may not be enough for most people, according to research published this week in Science, especially given that almost half of the water we consume comes from food.

"The original estimate of two liters a day comes from a slight miscalculation," Professor John Speakman from the University of Aberdeen told BBC Radio's Good Morning Scotland.

"The water that we'd need to drink is the difference between the total water that we need to ingest and the amount that we get from our food.”

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"The way they estimated the amount from food was by asking people how much they eat.”

"Because people under-report how much they eat, there's a misestimate and so you overestimate the amount of water that's needed."

Prof. Speakman continued by saying that a high turnover rate does not require that everyone consume the same volume of water.

"Even if a male in his 20s has a water turnover of 4.2 litres per day, he does not need to drink 4.2 litres of water each day," he added.

"About 15 per cent of this value reflects surface water exchange and water produced from metabolism.”

"The actual required water intake is about 3.6 litres per day. Since most foods also contain water, a substantial amount of water is provided just by eating.”

"This study shows that the common suggestion that we should all be drinking eight glasses of water is probably too high for most people in most situations and a 'one-size-fits-all policy' for water intake is not supported by this data."

People only require about 1.5 to 1.8 liters of water per day, according to estimates.