Is it safe?
The BIA Method is very safe. It sends an extremely weak electrical current - (50 kHz/500 micro Amp) that is painless, safe, and non-detectable. While there is no historical or clinical evidence that pacemakers are affected by bioimpedance testing, pacemaker manufacturers recommend that persons with pacemakers should avoid external electrical currents.
Is it accurate?
As long as the BIA Testing Conditions are maintained, BIA is accurate and highly reproducible. This is unlike the skinfold caliper where the skill of the technician, the accuracy of the calipers, the placement of the caliper during measurement, and the individual’s fat patterns can cause errors greater than 5%.
In clients who have varying body water contents, BIA may not give an accurate body fat measurement. However, BIA is still a good method for monitoring changes in body fat in these individuals. Clients who may have varying body water contents include: the elderly, children, body-builders, athletes, individuals with illness, individuals experiencing swelling, individuals who have osteoporosis, women who are pregnant, or individuals undergoing dialysis.
In a study published in the Journal of the American Diet Association, the foot-to-foot bioelectrical impedance analysis (BIA) was shown to be as accurate as the traditional foot-to-hand analysis.
How does it work?
Bioelectrical Impedance Analysis (BIA) operates by passing small electrical signals through the body via the footplate electrodes. The current is induced and the voltage drop measured via four metallic footplates situated within a conventional weighing scale. The heels of the feet are placed on two of the plates while the toes are placed on the other two plates, which act as separate electrodes. The electrical current is carried via the anterior plate (toes) and the voltage drop is measured across the posterior electrode (heel). The conducting ability of bodies tissues is then used to calculate the amount of fat mass, lean mass, bone mass and basal metabolic rate.