Body composition
measurement refers to the measurement of many functions of the human body such as fat, water and muscle. By completing the measurement of the body’s impedance, inputting information such as gender, age, height, etc., and then deeply integrating the body composition analysis model verified by a large number of samples, the body fat rate, muscle rate and many other physical signs data are accurately measured.
Measurement methods
Under Water Weighing（UWW）
Air Displacement Plethysmograph（ADP）
Dual Energy X-Ray Absorptiometry（DEXA）
Bioelectric Impedance Analysis（BIA）
Considering the accuracy and convenience of measurement, the Bioelectric Impedance Analysis (BIA) is currently the main flow measurement method. The subsequent presentations are based on the BIA .
Operating Principle
For the whole human body is composed of a large number of cells, so the equivalent model of the human body can be referred to the figure on the right.
The fluid between cells of biological tissues can be considered as electrolytes,
- DC signal through biological tissue, current will flow through extracellular fluid
- Low frequency signal less than 50KHz, the current mainly flows through the extracellular fluid, the measurement is the extracellular fluid resistance
- High frequency signal greater than 200KHz, current can be passed through the cell membrane, the measurement is the resistance of the inner and outer cell fluid
It is reasonable to measure the same person at different frequencies and have different impedance values.
The higher the frequency, the lower the impedance value.
Body composition algorithm
- Measure the impedance of the human body by introducing a certain frequency of current into the body
- Bio-impedance, weight, height, age, gender, and population information can be combined with big data models to establish correlation with body composition
- The body composition analysis model established by the above big data is the body composition algorithm
Bio-impedance and frequency are related, so the body composition algorithm usually applies a fixed frequency.
The current market mainstream algorithm single frequency for 50KHz; dual frequency for 20KHz and 100KHz.
Body fat scales include：
- Weighing.Integrated 24-bit Delta Sigma A/D converter;
- Bio-impedance.Integrated anmulti-frequency AC body fat measurement circuit;
- Heart rate.Heart rate data can be measured by using the multi-frequency AC bio-impedance circuit.
Body composition model
Application Circuits
Product Forms
- DC Body Fat Scale
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- Poor body fat correlation
- Poor repeatability
- AC Body Fat Scale-Mainstream Products
- Excellent body fat correlation
- Good repeatability
- High market acceptance
- High added value for measuring heart rate and other parameters
