It is a widely held belief that a person must drink at least eight glasses of water in a day, however, a new study has contradicted this view which says that it might be “too much”.

A recent study, published in Science, found that the recommended eight glasses of water were more than the required amount, BBC reported. 

As per the estimates, people only need about 1.5 to 1.8 litres of water as they also intake water from food.

“The original estimate of two litres a day comes from a slight miscalculation,” Professor John Speakman from the University of Aberdeen told BBC. 

“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.

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

The scientist said that asking people how much they eat is a common practice to estimate the amount of water intake that comes from food. He, however, said that following this method could result in misestimation as people “under-report” the amount of their food intake.

The study

There have been countless studies to find the correct answer to the question but the surveys applied to small samples of people. However, this new study was conducted through collaboration across the globe, in which the scientists used a stable isotope technique.

The survey involved 5,604 individuals aged between eight days and 96 years old, from 23 different countries. Some of the hydrogen molecules were replaced by a stable isotope of the element called deuterium in a glass of water the participants of the survey consumed.

Deuterium is an element naturally found in the body so the rate of its elimination showed how quickly the water in the body turned over.

It was discovered that people with a higher water turnover generally need to drink more water, while energy expenditure is the biggest factor in water turnover.

‘Just an adage’

Meanwhile, CNN’s senior medical correspondent Elizabeth Cohen said that drinking more than needed water is just “an adage” and does “no harm” to the human body.

When asked how much water should people drink, Cohen said that people only need to observe the colour of their urine instead of counting the glasses of water they consume, to see if they are drinking enough water.

As per the study, a person is considered healthy and hydrated if the colour of their pee is pale straw. The “amber or honey” coloured urine indicates mild dehydration while “syrupy or brown ale” coloured pee shows that a person is experiencing “worrisome dehydration” which could be a sign of liver disease.

She said that the symptoms are well known in a country with hotter weather.

“If you’ve yellow pee, that’s not good,” she translated an Israeli song, saying that everyone needs to learn that.