All You Need To Know About Bioelectrical Impedance Analysis

Measurement of Body Composition as an effective preventative measure and treatment of health conditions and weight control has gained a lot of popularity in recent times. Although there are a number of methods used today for the measurement of body composition, bioelectrical impedance analysis is particularly popular because of its ease of use, portability, and inexpensive nature.  

What is Bioelectrical Impedance Analysis (BIA)?

Bioelectrical Impedance Analysis, which is also referred to as bioelectrical composition analysis, is a quick and non-expensive tool that is used to measure body composition and how it may change over time. It was initially used by Lukaski et al. in 1985 to measure the fat-free mass in the body – however, since then, the parameters which may be measured by this technique have highly improved. It is currently one of the most popular body fat analyzers due to its ability to assess BIA body fat efficiently.  Moreover, due to increased awareness about the ease and inexpensive nature of this biometric impedance analysis system, the BIA body composition is largely investigated in clinical trials today. (1)

This technique allows the measurement of electrical current, which is of alternating manner as it passes through the body. The current which is introduced into the body is made to mainly pass through the upper and lower limbs and flows through the water pool of the body. Recent advances in technology have also enabled the measurement of impedance body composition by using a diverse range of frequencies, which can help differentiate the compartments of the body more efficiently.

How Does Bioelectrical Impedance Analysis Work?

The Bioelectrical Impedance Analysis works by determining the impedance which is faced by an electrical current as it passes through the human body. It usually involves the placement of two electrical sources on the feet and hand’s dorsal surface. This is accompanied by the placement of electrode sensors on other regions of the body, like the prominence of the wrist and the ankle. While the electrodes which are placed distally work by producing a current of 50 kHz frequency, the electrodes at the medial end work by detecting any drop in the voltage as it passes through the body. The resistance, which is displaced by the analyzer at the end, is then used to calculate the composition of different components of the body. (2)

What Is The Validity And Reliability Of Bioelectrical Impedance Technology?

Reliability and Validity are two important factors, which help determine how well a device is able to measure something and is a major requirement for testing systems. While Reliability determines how consistent the readings are every time the measurement is made, Validity determines the accuracy of the measurement. The Bioelectrical Impedance Analysis Accuracy and Reliability and have been tested in numerous studies over the years. One such study, which was conducted on male and females soldiers, used The Bioelectrical Impedance Analysis to measure the body composition. The results of the study illustrated the Bioelectric Impedance Analysis to be the most reliable and valid method amongst all others which were used in the study. (3)

Measuring Body Composition Using Bio Electrical Impedance Analysis

What is Body Composition?

Body Composition is a commonly used term in the fitness and health sectors and helps determine the percentage of different elements found inside the body. The assessment of these factors helps the doctor evaluate the current level of health of the individual and the potential changes that they might need to make to their lifestyle and diet.   What differentiates body composition analysis from the measurement of one’s weight on the weight scale is that two people with the same weight may have different levels of fat and protein in their bodies. Since it is the amount of fat and protein in the body which determines the health level of an individual, sometimes the measurement of just one’s weight is not enough.

These measurements are also of particular interest to the nutritionist, as the body composition measured can provide insights into the nutritional status of the individual, which can then help the nutritionist plan out the diet according to their requirements. (4)

How Does Bioelectrical Impedance Analysis Indicate Body Composition?

The electrical impedance, which is measured by the Bioelectrical Impedance Analysis, consists of two main factors known as Resistance and Reactance. While resistance helps measure the total water content of the body, Reactance helps measure the Body Cell Mass. These measurements can then be applied to numerous equations, which can help determine the body composition. (5)

The parameters which may be measured by the Bioelectrical Impedance analysis include:

  • Body Cell Mass:

Body Cell Mass includes all the cells, which are able to have an influence on the metabolism. These may include cells of the muscles, nervous system, and even the internal organs.

  • Body Cell Mass Percentage:

This is the percentage of Body Cell Mass, which is found in the Fat-Free Mass of the body.

  • Extracellular Mass:

Extra Cellular Mass includes all the cells of the body which are inactive metabolically and play no part in the metabolism of the body.

  • Fat-Free Mass:

Fat-Free mass of the body contains all the cells of the body, which makes up the part of the body that does not contain fat. This includes the bones, vital organs, and water.

  • Total Body Water:

The Total Body Water is the measurement of the amount of water in the body. This measurement in healthy adult males ranges from 60 to 63%; on the other hand, it is found within the range of 52% to 55% in healthy adult females.

How Does Bioelectrical Impedance Analysis Help The Individual Meet Fitness Goals?

By helping evaluate components like total body water, fat-free mass, body cell mass, and extracellular Mass, Bioelectrical Impedance Analysis can help in the assessment of any changes in the body which may be accompanied by a pathological process or unhealthy lifestyles. This may help the individual plan out a diet or exercise plan that is tailored particularly to their health needs.

Types of Bioelectrical Impedance Analysis Devices

Bioelectrical Impedance Scales

The four bioelectrical impedance scales help calculate the percentage of body fat along with the fat-free mass using certain equations that have been introduced by the manufactures. The Bioelectrical Impedance Scales that are commonly used today include:

  • Biodynamics: This is a single frequency device with a hand-to-foot machine that is accompanied by adhering electrodes.
  • Tanita TBF-543: This is a foot-to-foot device, which uses a bipolar single frequency of 50 kHz.
  • Tanita BC-545: This is a Dual Frequency Device, which uses both 50 kHz and 6.25 kHz.
  • InBody 520: This is a multifrequency device that uses a combination of 8 electrodes arranged in a tetrapolar arrangement.

Handled BIA

The Handled Bioelectrical Impedance Analysis Devices work by having the individual stands on a scale while holding the handles of the device at a chest level. This allows the current to be passed through the body, going from one hand to the other. Some commonly used handles BIA devices include American Weights and Measures Body-Comp Scale, CA, and Rancho Santa Fe.

Whole Body Impedance Devices

Whole Body Impedance Devices allow a small current to be passed through the entire body, which is often made to flow from the wrist of one side to the ankle of the other side. This is followed by the measurement of the corresponding voltage, which is then used to calculate the impedance. These types of devices commonly use a combination of four electrodes, where two electrodes are used to send the current into the body, while the other two are used to measure the drop in the voltage.

DSM-BIA

DSM-BIA is a Digital Body Composition Analyzer and involves the use of an analyzer, which measures the complete composition of the body within a matter of few minutes. The diameters that may be measured by this device include the weight, along with the compositions of fat, muscle, protein, water, bone, Fat-Free Mass, PBF, Body Mass Index, Waist to Hip Ratio, and Total Body Water. Studies have found this method to be most effective at measuring the lean mass of the body and also a valid tool for the measurement of complete and segmental compositions.

BIA Tech in Visbody

Visbody is a highly popular body composition analysis tool, which is known for its quick results and high accuracy. It is essentially a 3D body scanner, which allows the complete reconstruction of the body and helps the individual thoroughly understand the anatomy of their body and the different components inside it. It also includes a highly effective Bioelectrical Impedance Analysis tool which helps it measure the fat mass, lean body mass, protein mass, total body water, ratio of the fat and muscle, and rate of basic metabolism in the body.

Hence, unlike other technologies, you may not have to rely on the doctor completely to make you understand the readings and results of the BIA, but the three-dimensional avatar of the body, short scan time, and easily interpretable results make it highly convenient for you as well.

References:

  1. Kyle UG, Bosaeus I, De Lorenzo AD, Deurenberg P, Elia M, Gómez JM, Heitmann BL, Kent-Smith L, Melchior JC, Pirlich M, Scharfetter H, Schols AM, Pichard C; Composition of the ESPEN Working Group. Bioelectrical impedance analysis–part I: review of principles and methods. Clin Nutr. 2004 Oct;23(5):1226-43. doi: 10.1016/j.clnu.2004.06.004. PMID: 15380917.
  2. Kushner RF. Bioelectrical impedance analysis: a review of principles and applications. J Am Coll Nutr. 1992 Apr;11(2):199-209. PMID: 1578098.
  3. Aandstad A, Holtberget K, Hageberg R, Holme I, Anderssen SA. Validity and reliability of bioelectrical impedance analysis and skinfold thickness in predicting body fat in military personnel. Mil Med. 2014 Feb;179(2):208-17. doi: 10.7205/MILMED-D-12-00545. PMID: 24491619.
  4. Andreoli A, Garaci F, Cafarelli FP, Guglielmi G. Body composition in clinical practice. Eur J Radiol. 2016 Aug;85(8):1461-8. doi: 10.1016/j.ejrad.2016.02.005. Epub 2016 Feb 15. PMID: 26971404.
  5. Wells JC, Fewtrell MS. Measuring body composition. Arch Dis Child. 2006;91(7):612-617. doi:10.1136/adc.2005.085522

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