(BIA) Bioelectrical Impedance is measured when a very small electrical signal carried by water and fluids is passed through the body. 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. By using the impedance measurements along with a person’s height & weight, gender, age, fitness level and body type, it is possible to calculate the percentage of body fat, phase angle, fat-free mass, hydration level, and other body composition values.
Using BIA to estimate person’s body fat assumes that the body is within normal hydration ranges. When a person is dehydrated, the amount of fat tissue can be overestimated. Factors that can affect hydration include not drinking enough fluids, drinking too much caffeine or alcohol, exercising or eating just before measuring, certain prescription drugs or diuretics, illness, or a woman’s menstrual cycle. Measuring under consistent conditions (proper hydration and same time of day) will yield best results with this method.
Centaur Imaging & Wellness uses the Quantum IV unit from RJL Systems, the pioneer of bioelectrical impedance analysis (BIA) and related sciences since 1979. RJL Systems has more than 1,000 abstracts and peer review articles have been written about BIA using RJL Systems instruments. RJL instruments sets the standard for body composition.
The RJL Systems Quantum series assesses three compartments of your body (fat & fat-free cells, tissue, and water) composition with accuracy and repeatability, which is a significant step beyond all other analyzers. Most equipment only reports body composition in two compartments: fat and fat-free mass.
RJL instruments and software assess body composition, or in other words, the different structures or parts of your body. The BIA can measure and track changes in the amounts of body fluids, fat, and lean body mass, which includes your muscles and organs. The BIA distinguishes where the water is located in your body – either intracellular or extracellular. Functionally the BIA assesses how much of your body is acting as functioning cells (called the body cell mass or “BCM” on the report), transport tissue (extracellular mass or “ECM” on the report) or storage cells (fat).
BIA Pre-test protocol
- 1. Do not eat for 4 hours prior to testing.
- 2. Do not exercise for 12 hours prior to testing.
- 3. Do not consume alcohol for 24 hours prior to testing.
- 4. Drink at least 1 litre of water one hour before your test. You may use the restroom as needed.
- 5. Do not drink caffeine the day of your test.
- 6. Do not wear pantyhose.