Impedance testing, a technology that has been credited to NASA for its development from the 1960’s onwards, is measured when a safe electrical signal is passed through the body, carried by water and fluids. Impedance is greatest in fat tissue, which contains only 10-20% water, while fat-free mass, which contains 70-75% water, allows the signal to pass much more easily.

In recent years it has been researched, refined and increasingly validated as a tool for measuring body composition (weight, body fat percentage, muscle percentage, water percentage, bone mass). The technology is now referred to as bio-electrical impedance analysis (BIA).

BIA measurements can be affected by – hydration status, caffeine, alcohol, recent exercise, prescription drugs, diuretics, menstrual cycle, and illness.

Nature’s Medicine uses BIA scales that uses the hospital grade standard Dual Energy X-ray Absorptiometry (DEXA) as a reference model. The scales have been reliably tested to be within 5% accuracy of DEXA.

This measurement tool allows the calculation of the potential risk to your future health that might result from carrying extra weight.  These measurements are taken together with other biometric measurements to identify potential risk factors.  These measurements are indicative, consistency is key in monitoring results, for example, weighing at the same time of day.

Note: BIA testing is not suitable for pregnant women.

References –

http://jap.physiology.org/content/jap/103/5/1688.full.pdf 

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8912424&fileId=S0007114512003698 

http://lsda.jsc.nasa.gov/lsda_data/dataset_inv_data/NAG91039__2580458538.pdf_BRC_NAG91039_2011_258_050905.pdf 

http://lsda.jsc.nasa.gov/scripts/experiment/exper.aspx?exp_index=1249

http://www.sciencedirect.com/science/article/pii/S0167876003001430

http://www.sciencedirect.com/science/article/pii/S0272638610010462

 

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