BODY COMPOSITION ANALYSIS
What do we measure in Body Composition Analysis?
This is a painless test, which includes the following measurements:
- Body weight
- Percentage of Fat
- Total Liquids%
- Muscle mass
- Physical condition
- Bone Mass
- Basic Metabolic Rhythm
- Metabolic Age
- Estimation of Body Mass Index (BMI)
- Visceral Fat Levels
Measurement with bioelectric resistance . Requires special measuring instruments that have metal plates (special machines or scales) and is fast and quite reliable. It is based on the assumption that the tissues of the body behave like conductors of electricity and that the flow of this current will follow the path that presents the least resistance. The method measures our lean body mass and then calculates our fat by subtracting it from our total weight . It has an error rate of 3.5% to 5.0% and its biggest disadvantage is that it is affected by the level of hydration of the examinee. Diet, drink, or exercise, dehydration, and fluid retention before the measurement undermine the effect of fat measurement.
Fat measurement is very important not so much for the course of our diet (this is something that depends on us), as for the right and accurate calculation of the "type" of weight we lose .
It's very important to know what percentage of the total weight we lose during our diet corresponds to fluid and muscle tissue and if we finally lose" substantial "weight.
The bioelectrical resistance (BIA) is based on the application of low AC current in the human body and measurement of its conductivity. The subject should remove metal objects that come in contact with his body and either lie on a non-conductive surface in such a position that the hands do not come into contact with the torso and the body. The specialist will place electrodes with very low voltage current in one arm and one leg, but they may also be built into the fat meter and we just press or tap them. holding.
The human body functions as a conduit, closing the circuit and calculating the impedance, which it converts through a mathematical calculation into a percentage of body fat. body are good conductors of electricity, while fat is a poor conductor of electricity and with this assumption the measurement is made.
The examinee must be properly prepared, ie:
- Be in the fasting stage for at least 2-3 hours before the test
- Do not consume liquids for at least 2-3 hours before the measurement
- Have not done exhausting exercise at least 12 hours before the measurement
- Have not consumed alcohol for at least 24 hours before the measurement
- Have not consumed coffee, tea, soft drinks for at least 12 hours before the measurement
- For women not to have menstruation and it is preferable to measure in the middle of their cycle
- Do not take the blood pressure pill if it is a morning measurement
The BIA method is widely used to assess body composition. Calculates body fat and lean body mass (water and muscle tissue). It also calculates the body mass index ( D .Μ.Σ. ) and makes a calculation through mathematical operations of the basic metabolic rate.
It is a method that is fast, safe, painless and easily accepted by the examinee. Regarding the reliability of the method, the relative error is estimated at about 2%. Contraindicated in pregnant women, nursing mothers and people with a pacemaker.
For BIA, it is a very common method of assessing body composition. This method is based on the fact that lean body mass, which contains a large amount of fluids and electrolytes, is a good conductor of electricity, while adipose tissue is a poor conductor. During the measurement, a low-voltage alternating current (frequency usually 50 kHz) is applied to the human body and the resistance and capacitive resistance are measured. This passage is made through special electrodes, which are placed either at the two upper extremities, or at the upper and lower extremities, or at both lower extremities, with the patient standing, sitting or lying down. Essentially, the measurement estimates the total resistance that the tissues cause to the passage of electricity through the body. In this way, the total body composition in water is directly estimated and, since body water constitutes 73% of lean mass, lean body mass is also indirectly calculated. In addition, subtracting lean body mass from total weight calculates total body fat (Kushner, 1992). BIA is also a useful method of monitoring changes in body composition during a dietary intervention.
The bioelectric impedance method is easy to use. The repeatability of its measurements depends on the accuracy of the measuring device, but also on various biological factors (eg body hydration, dietary intake, level of physical activity, how long the person is lying down). The accuracy of the BIA results also depends on the estimation equation of the body composition used. Ideally, to estimate the body composition of a group of individuals it is necessary to choose an equation from the literature, which should have emerged from a population with the same or even similar characteristics, in terms of sex, age, race, muscle tissue hydration, obesity levels and other factors (Kushner, 1992).