Bioelectrical Impedance Analysis

Bioelectrical Impedance Analysis (BIA) is a commonly used method for estimating body composition, in particular body fat and muscle mass. In BIA, a weak electric current flows through the body and the voltage is measured in order to calculate impedance (resistance) of the body.

Bioelectrical Impedance Analysis:

• Uses a small electric current to differentiate between fat (low water content) & other body tissue (higher water content)
• Gives an estimate of total body water
• Very user-friendly and can give good results for comparative purposes.

Issues to be aware of with BIA:

• Test protocols need to be strictly adhered to for good comparative results
• The test can be affected by body position, hydration, food and beverage consumption, air and skin temperature and recent physical activity
• Sensitive to the density of components of the body
• Arm and leg electrodes will give more accurate results than the arm to arm electrodes.

To explore BIA further, we advise you to access this course reading – Bioelectrical impedance analysis to estimate body composition in children and adolescents