Errors in the estimation of hydration status from changes in body mass

Hydration status is not easily measured, but acute changes in hydration status are often estimated from body mass change. Changes in body mass are also often used as a proxy measure for sweat losses. There are, however, several sources of error that may give rise to misleading results, and our aim i...

Full description

Saved in:
Bibliographic Details
Published in:Journal of sports sciences 2007-05, Vol.25 (7), p.797-804
Main Authors: Maughan, Ronald J., Shirreffs, Susan M., Leiper, John B.
Format: Article
Language:English
Subjects:
Biological and medical sciences
Body Mass Index
Dehydration - physiopathology
Dehydration - prevention & control
Drinking
Fundamental and applied biological sciences. Psychology
Glycogen
Health Status Indicators
Humans
metabolism
Reproducibility of Results
sweat loss
tonicity
United Kingdom
Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
Water
Water balance
Water Loss, Insensible - physiology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Hydration status is not easily measured, but acute changes in hydration status are often estimated from body mass change. Changes in body mass are also often used as a proxy measure for sweat losses. There are, however, several sources of error that may give rise to misleading results, and our aim in this paper is to quantify these potential errors. Respiratory water losses can be substantial during hard work in dry environments. Mass loss also results from substrate oxidation, but this generates water of oxidation which is added to the body water pool, thus dissociating changes in body mass and hydration status: fat oxidation actually results in a net gain in body mass as the mass of carbon dioxide generated is less than the mass of oxygen consumed. Water stored with muscle glycogen is presumed to be made available as endogenous carbohydrate stores are oxidized. Fluid ingestion and sweat loss complicate the picture by altering body water distribution. Loss of hypotonic sweat results in increased osmolality of body fluids. Urine and faecal losses can be measured easily, but changes in the water content of the bladder and the gastrointestinal tract cannot. Body mass change is not always a reliable measure of changes in hydration status and substantial loss of mass may occur without an effective net negative fluid balance.
ISSN:0264-0414
1466-447X
DOI:10.1080/02640410600875143