What's this
What is the impedance balance?
The impedance scale is an electronic instrument designed for:
- Measure body weight - definable as the force exerted by the mass (quantity of matter) attracted towards the center of the planet thanks to the earth's gravity
- INDIRECTLY estimate, through the principle of impedance measurement - or impedance measurement - different parameters related to the composition of the same, for example the percentages of lean mass (FFM) and fat mass (FM), state of hydration, cell mass, etc.
For more information on the functioning of bio-impedancemetry we recommend reading the articles: The Bioimpedance and Values of BIA (Bioimpedance) - How to interpret them.
How to use
How to use the impedance scale
The impedance scale is very easy to use, although some details may change depending on the model. In fact, there are many types of impedance balance, which can be classified into approximately two macro-groups: with and without electrodes. The impedance-free scales without electrodes are the least reliable and the cheapest; those with electrodes, which can be further differentiated according to the technology, are more accurate but even in this case it is not certain that they will fully satisfy the needs of a particularly demanding user. We'll talk better about this in the next few paragraphs.
To use the impedance scale it is therefore necessary:
- Always be in the same condition: if it is not possible to access it the same day of the week, it is better to choose another time that has the same characteristics as the previous one
- Be naked, preferably without necklaces, earrings, rings and piercings
- Being totally fasting and even better if in an empty intestine - without running the risk of getting dehydrated - for this reason many prefer to use the impedance scale in the morning, before breakfast and after going to the bathroom
- Being distant, from a temporal point of view, from an intense, prolonged or otherwise demanding workout; sometimes the balance of body fluids, electrolytes and glycogen is barely recovering in just one day
- Correctly enter the data requested by the device: age, gender, height, etc.
- Position or hold any electrodes, sometimes available in the form of a handlebar
- Repeat the measurement at least 2-3 times to make sure of the validity; if necessary, average the data.
What is it for
What is the impedance balance for?
Weight and body composition monitoring can be useful for different purposes, but the most common are two: aesthetic and health. The aesthetic goal is in fact the main reason that pushes users to buy an impedance balance. On the other hand, the health-giving factor, lower in frequency, is the most important reason.
"Apparently attractive" - compared to professional bioimpedentiometers - due to the value for money, impedance scales are widely sold items. Today it is known that the evaluation of nutritional status cannot be based exclusively on the weight parameter, but must also take into account many variables - some of which are detected with other methods and tools . Let's see some of them:
- Ratio between fat-free mass and fat mass and relative percentages
- Magnitude of muscle mass
- Ratio between the so-called essential fat - necessary for survival - and the adipose - visceral and subcutaneous - white and brown - and relative percentages
- Amount of abdominal fat and its circumference, with greater attention to the visceral one - located inside the peritoneal cavity, around the organs
- Skeletal mass and importance on weight - called constitution
- Relationship between the latter and body height and / or segments - called morphological type
- Amount of water, both inside and outside the cells
- Cell mass
- Electrolytes etc.
Ultimately, the correct use of the impedance balance associated with other measurements such as, for example, the lengths of body circumferences - waist, hips, limbs, thorax etc. - and of stature, it contributes to accurate assessment of the state of nutrition. It remains to understand what its real applications may be and, possibly, the cases in which the impedance balance may prove necessary or even irreplaceable.
Observations and criticisms
Observations and criticisms on the impedance scale
Let's start by saying that the impedance balance is not only not essential, but in some cases it can be considered an instrument of doubtful reliability . These statements, indigestible to most - both professionals and self-taught - can be motivated by the following.
The impedance scale differs from the traditional scales due to the characteristic function of assessing body composition using the principle of impedance measurement. As we have already said, the latter is a method based on the measurement of impedance - bioimpedance or bio-resistance - to the passage of an electric current with low power and high frequency. In practice, the instrument releases a known current which, passing along the segments of the organism, is subjected to "obstacles" - resistances or impedances - which modify certain characteristics subsequently registered at the time of reception / arrival. Now, taking for granted the continuous technological improvements as well as the development of excellent quality products, it is difficult to believe that these "enriched" bioimpedentiometer scales can offer the same accuracy as the proper bioimpedentiometers, although it is understandable that only field technicians can understand the gap. In fact, the use of these devices is rather delicate, it is necessary to respect a strict protocol to avoid human errors as much as the instrumental misinterpretation of the data. This is because bioimpedance is an "indirect" system, which offers numbers processed from other data - not only the electrical characteristics, but also values to be entered manually such as weight, height and even lifestyle (athlete or ordinary person ). Bio-impedancemetry is therefore extremely susceptible to error. Having said this, many consider this margin of "negligible" inaccuracy, while others consider the instrument almost useless. How to realize it? It is soon said; most impedance scales - especially medium-low range - offer different results for consecutive measurements; the results, not being repeatable, are totally lacking in precision and therefore of practical use.
Then, even if the results were reliable, why constantly monitor your body composition? A thousand answers could be given to this deliberately provocative question, but all but one can be considered "unconvincing". The real usefulness of bioimpedance analysis is the measurement of some indicators of good health related to the state of nutrition. To give an understandable example, bioimpedance is essential in monitoring the state of hydration in the event of malnutrition, debasement, severe underweight etc .; for example, as occurs in patients with anorexia nervosa, functional insufficiency of important organs, etc. However, it must be specified that, in the clinical field, many do not neglect the precision of the instrument and are oriented on specific devices rather than on impedance scales.
To be honest, not even an overweight person needs to use an impedance scale. If the fat mass is frankly excessive, it is not necessary to have the instrumental confirmation; likewise, if the alleged excess is slight, therefore harmless, there is no reason to investigate further.
Then there are transversal applications. Several technicians and professionals suggest the use of the impedance balance in the case of slimming therapy to assess, specifically, that weight reduction is frankly attributable to the decrease in fat mass, not water or muscle mass. On balance, since weight-loss therapy must be balanced and respect certain safety limits precisely to avoid dehydration and notching of the muscles, it would be sufficient to simply use professionalism or simple common sense.
Others argue that the impedance balance is essential to understand if, in a protocol of aesthetic culture, an increase in muscle mass and / or a decrease in fat mass actually takes place. If the two processes occur simultaneously, the weight could remain initially stable or fall slowly distorting the evaluation of the necessary calories or of the motor activity program. Fortunately, everyone knows that passing from a sedentary lifestyle to sports, in particular with an emphasis on muscle building, an immediate and significant - but only initial - global hypertrophy occurs. The doubt is therefore not worth the trouble.
There are also those who use the impedance scale to estimate only the improvements in the increase of muscle mass. Even in this case it is difficult not to be perplexed. We know that natural bodybuilding is an thankless activity; after only a few years of "serious" training, you get so close to your physiological limit that even gaining a kilogram in muscles becomes a real achievement. There is therefore nothing more frustrating than putting yourself on an impedance scale and seeing the same numbers every week, or be aware that any change could be due to a measurement defect.
In the experimental and scientific research field, on the other hand, bioimpedance analysis can be considered very useful, above all to offer useful data for technical and technological improvement. On the other hand, the experimental ones require a lot of accuracy to offer reliable results and even in this case it would be preferable to use a real bioimpedentiometer rather than a simple impedance scale.
