What is bioelectrical impedance analysis (BIA) and how does it work?
What is bioelectrical impedance analysis (BIA) and how does it work?
Overview
Bioelectrical impedance analysis (BIA) is an electrical method used to estimate body composition. It is commonly found in scales with conductive footpads or handheld devices. BIA measures the speed of an electrical signal as it travels through the body — specifically its resistance (impedance) — to quantify:
- Total body water
- Fluid volumes
- Body cell mass
- Fat-free mass
- Body fat percentage (estimated using impedance readings combined with height and weight)
How BIA Works
Adipose (fat) tissue does not contain water — it is anhydrous. All body water and fluids are contained within fat-free mass (muscle, organs, bone, etc.). Because the electrical signal travels through water-containing tissue, BIA can distinguish between fat mass and fat-free mass based on how quickly or slowly the signal moves.
BIA uses the impedance measurement along with the client's height and weight in established equations to estimate body fat percentage.
Notes
- BIA is a widely available, fast, and non-invasive assessment method.
- Accuracy can vary by population: BIA tends to overestimate body fat in lean individuals and underestimate body fat in overweight or obese individuals.
- Results should be interpreted with awareness of these known limitations.
If this resolves your issue, no further action is needed.
If the problem persists, contact support and include: the device model and software version being used.
Applies to: All Styku configurations using BIA integration