Bioimpedance
The measure of a biological tissue's opposition to the flow of electric alternating current.
Governing formula
Z = R + i X_c = √(R² + X_c²)
SI unit
Ω (Ohms)
In depth
Cell membranes act as capacitors (reactance X_c), while intracellular and extracellular fluids act as conductors (resistance R). Multi-frequency bioimpedance analysis (BIA) determines total body water, fat-free mass, and cellular health.
Examples in the real world
Bioelectrical Impedance Analysis (BIA) scales estimating body fat percentage and hydration status.