In the study done by Going and colleagues, it was found that the 98% of weight change due to dehydration was measured by DXA. (Human Body Composition, By Steven Heymsfield, Pg 75) A normal variation in hydration level (1-3 %of body weight) has very little affect on measurement by DXA method. Variation in Hydration level blazes DXA estimates of percentage fat only 1-2.5 %.This interprets that Hydration Level doesn't have much affect on DXA measurement.
B. Hydration Level and BIA Test: "In an experiment done, with decrease in Hydration level, Bioelectric Impedance (BI) decreased from 14.4 5.3% to 12.3 5.3%, After Rehydration, BI % increased to 15.5 5.8%. Similar findings occurred when subjects were super hydrated (Normal-BI = 13.2 5.3%; Super hydration -BI = 15.4 5.6%)." (SAUNDERSM. J. (1) ; BLEVINSJ. E. (1) ; BROEDERC. E. (1) )
B. Hydration Level and SKINFOLD: With the increase level of Water in the body, the Value in Skin fold test increases. High extra cellular water in subcutaneous tissues causes thickness of and hence the value calculated is incorrect.
"Martin, Drink water and Clays(1992) reported that variation in skin fold compressibility may be an important limitation of this method. ...