Hydration status and total body water (TBW) in humans may vary in special populations such as athletes and age groups. This variability may lead to inaccurate body composition measurements using conventional models that assume normal hydration. In this study, we investigate how to isolate hydration status from lean mass measures in multiple methods of body composition. We will also focus on how to account for factors such as skin temperature, skin moisture, differences of intracellular water (ICW) and extracellular water ECW), and skin pad placements.

The combination of the four major compartments of the body (lean mass, fat mass, bone, and water) is most accurately represented by the gold standard of measuring the human body’s composition. The combination of these tests creates what is called the four-compartment model (4CM). Body composition and hydration status can be measured by various technologies like dual-energy x-ray absorptiometry (DXA), air displacement plethysmography (BodPod), underwater weighing (UWW), bioelectrical impedance spectroscopy (BIS), bioelectrical impedance analysis (BIA), deuterium dilution analysis (DDT), 3-Dimensional Optical scans or predicted via anthropometry and skinfold techniques.

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3D optical scans via Fit3D

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Bioelectrical impedance spectroscopy (BIS) via InBody

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Air Displacement Plethysmography via BODYPOD

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Dual-Energy X-ray Absorptiometry (DXA)

It has been demonstrated in previous research that the variance associated with skin temperature, moisture, and placement of the electrode pads can overpredict an individual’s TBW and underpredict and individual’s fat mass. Further research by Nickerson et al. suggests that skin hydration and temperature status varies and may affect body composition measurements if not accounted for.

In this study, we will attempt to create a correction factor within these possible skin hydration and temperature variations to create a more accurate method for the four-compartment model.