Variation in human water turnover associated with environmental and lifestyle factors

Water is essential for survival, but one in three individuals worldwide (2.2 billion people) lacks access to safe drinking water. Water intake requirements largely reflect water turnover (WT), the water used by the body each day. We investigated the determinants of human WT in 5604 people from the ages of 8 days to 96 years from 23 countries using isotope-tracking (2H) methods. Age, body size, and composition were significantly associated with WT, as were physical activity, athletic status, pregnancy, socioeconomic status, and environmental characteristics (latitude, altitude, air temperature, and humidity). People who lived in countries with a low human development index (HDI) had higher WT than people in high-HDI countries. On the basis of this extensive dataset, we provide equations to predict human WT in relation to anthropometric, economic, and environmental factors.

Automated summary

This study investigated the determinants of human water turnover in different age groups and countries. The results show that age, body size and composition, physical activity, socioeconomic status, and environmental characteristics are closely related to water turnover. People living in countries with a low human development index have higher water turnover. Predictive equations for human water turnover in relation to anthropometric, economic, and environmental factors are provided based on the extensive dataset.