It is common to hear people say that someone should drink around eight glasses of water per day. But it is still unclear where this assertion came from. According to Science Alert, evidence of this assertion has been debunked over time. 

Retroactivity measures  how much water people take 

Studies measuring water consumption use retroactivity in measuring how much water individuals drink. Self-reports produced using this method are inaccurate and imprecise. 

A recent study in Science examined a sample of 5,600 people across 26 different countries and a range of ages to more precisely estimate the amount of water people need.

Participants in the trial received 100ml of water containing 5% doubly tagged water. This water is frequently used in metabolism-related experiments because it makes it possible to track how quickly chemicals flow throughout the body. Deuterium, an isotope of hydrogen, is present in this water. In addition, they have an extra neutron within their nucleus, which doubles their weight compared to ordinary hydrogen atoms.

Comparing this water to ordinary water, it was 10% thicker. However, drinking small amounts is harmless.

Activity level, sex and age determine the amount of water consumption 

In a recent survey, the researchers found that factors such as activity level, sex, age, and weather significantly impact the daily consumption of water. Simply said, the needs change based on specific environmental and lifestyle conditions.

Science Alert points out that the investigators said there was no “one size fits all” approach to water intake. They added that there is no scientific basis for the widely accepted advice to drink eight glasses of eight-ounce water daily.

According to the University of Wisconsin-Madison, male participants in their 20s had the greatest water turnover rates. In contrast, women reached a plateau between the ages of twenty and fifty-five.

Newborns had the biggest water replacement rate, with about 28% of their water being replenished daily.

These variations in water turnovers could be mostly attributed to disparities in athletic ability and physical activity. The second most important factor was sex.