Scientists say eight glasses of water a day may be too much

New probe has recovered that the recommended 8 glasses of h2o a time whitethorn beryllium excessively much.

Scientists from the University of Aberdeen discovered the recommended intake of 2 litres of h2o a time was often much than radical needed.

Given astir fractional of the regular intake of h2o comes from food, scientists estimation radical lone truly request astir 1.5 to 1.8 litres per day.

The latest findings were published successful Science this week.

Previous probe into h2o requirements utilized surveys applied to tiny samples of people.

Prof John Speakman from the University of Aberdeen told BBC Radio's Good Morning Scotland: "The archetypal estimation of 2 litres a time comes from a flimsy miscalculation.

"The h2o that we'd request to portion is the quality betwixt the full h2o that we request to ingest and the magnitude that we get from our food.

"The mode they estimated the magnitude from nutrient was by asking radical however overmuch they eat.

"Because radical under-report however overmuch they eat, there's a misestimate and truthful you overestimate the magnitude of h2o that's needed."

But scientists person present collaborated crossed the satellite to measurement nonstop h2o turnover utilizing a unchangeable isotope technique.

They surveyed 5,604 radical from 23 antithetic countries and aged betwixt 8 days and 96 years old.

Research progressive radical drinking a solid of h2o successful which immoderate of the hydrogen molecules were replaced by a unchangeable isotope of the constituent called deuterium.

It is recovered people successful the quality assemblage and is wholly harmless.

The complaint of elimination of the other deuterium shows however rapidly h2o successful the assemblage is turning over.

People with a higher h2o turnover usually request to portion much water.

Research recovered that this included those surviving successful blistery and humid environments and astatine precocious altitudes, arsenic good arsenic athletes and large and breastfeeding women.

Energy expenditure is the biggest origin successful h2o turnover. The highest values were observed successful men aged 20-35, who turned implicit an mean of 4.2 litres per day.

This decreased with age, averaging 2.5 litres per time for men successful their 90s.

Women aged 20-40 averaged a turnover of 3.3 litres, which besides declined to 2.5 litres by the property of 90.

But h2o turnover is not precisely adjacent to the request for drinking water, Prof Speakman said.

He said: "Even if a antheral successful his 20s has a h2o turnover of 4.2 litres per day, helium does not request to portion 4.2 litres of h2o each day.

"About 15% of this worth reflects aboveground h2o speech and h2o produced from metabolism.

"The existent required h2o intake is astir 3.6 litres per day. Since astir foods besides incorporate water, a important magnitude of h2o is provided conscionable by eating.

"This survey shows that the communal proposition that we should each beryllium drinking 8 glasses of h2o is astir apt excessively precocious for astir radical successful astir situations and a 'one-size-fits-all policy' for h2o intake is not supported by this data."

He said the probe represented a large measurement forwards successful predicting aboriginal h2o needs.

But determination tin beryllium negatives successful drinking excessively overmuch water.

"Clean drinking h2o isn't free," Prof Speakman said.

"If radical connected mean portion fractional a litre much than they request and you multiply that by 40 cardinal adults successful the UK, that means that we're needlessly drinking and peeing 20 cardinal litres of h2o that we person to supply.

"There is simply a outgo successful doing that."