The Turnover of Body Water as an Indicator of Health.

Abstract

Water homeostasis is essential for healthy living. Body water turnover, meaning the replacement of body water that is lost in a given period of time, has been examined in a number of previous studies, and a review of their results has yielded the following findings. Children up to 15 years of age show higher body water turnover than adults, although it is not clear how the aging process influences body water. Among people of similar age, the rate of body water turnover seems to be higher in those who exercise than in those who are sedentary. Therefore we hypothesized that healthy individuals have a higher body water turnover than unhealthy individuals whose metabolic balance, as indicated by water turnover, has broken down, and that a prolonged condition of excessively slow body water turnover may be associated with a lower level of metabolism. If so, body water turnover can be an indicator of human health. However, there is a paucity of information regarding water turnover rates in individuals with various physical characteristics. This study indicates the need for further investigation of body water turnover levels associated with significant changes in physiological condition and metabolic state.

Water Turnover Assessment in Overweight Adolescents

“…Water is the largest constituent in the human body (1). Total body water (TBW) constitutes ∼55% body weight in adolescents (2) and can vary depending on age, sex, and percentage body fat (3). Water turnover is defined as the input and output of water over a given period of time (4) and reflects body water homeostasis (3).…”

Implications of the variation in biological 18O natural abundance in body water to inform use of Bayesian methods for modelling total energy expenditure when using doubly labelled water

“…The DNSIYC cohort are younger than the NDNS cohort and it has been reported that water turnover is affected by age in children. 29 However, our own data in adults (unreported NDNS Y1 and 3 30 ) show that water turnover increases with age from about 20 years to 50 years of age, and so we would expect that the NDNS cohort would have greater water turnover if it was not for the fact that the DNSIYC cohort were breast-feeding. Levels of breast-feeding varied considerably from almost none to exclusively breast-feeding, as the average age of the infants was 11 months.…”

Dynamic Proteomics

“…The half-life of body water in humans is 7-10 days (Shimamoto & Komiya, 2000) and subjects can take sips of heavy water every day as outpatients for periods as long as several months (Messmer et al, 2005;Price, Holmes, et al, 2012;Shankaran et al, 2014). Labeling does not need intravenous administration or medical supervision, which allows measurements to be performed under free-living, ambulatory real-life conditions.…”