Is 8 Glasses a Day Overkill?

We’ve been conditioned to believe that a standard 8 glasses of water is required each day—but could that be too much?

New research published in Science found that the amount of water we need each day varies based on many factors.

The researchers studied 5,604 people from the ages of 8 to 96 years old from 23 countries and measured how much water the participants lost and replaced each day (a measurement called water turnover). They found that for most healthy adults, drinking 8 cups of water a day is unnecessary because water needs vary depending on age, sex, body size, physical activity level, athletic status, pregnancy, socioeconomic status, and environmental characteristics (latitude, altitude, air temperature, and humidity).

The researchers also found that people who lived in less developed countries had higher water turnover than people from developed countries.

While hydration should be prioritized, most people who pay attention to their bodies and drink when thirsty are likely drinking enough water.