Difference between revisions of "Body mass"
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{{MitoPedia | {{MitoPedia | ||
|abbr=''M'' [kg·x<sup>-1</sup>] | |abbr=''M'' [kg·x<sup>-1</sup>] | ||
− | |description=The '''body mass''', ''M'', is the mass [kg] of an individual (object) [x] and is expressed in units [kg/x]. The individual (object) is a countable quantity, therefore, the unit [x] is a dimensionless number. The SI unit for mass (of a system), ''m'', is [kg] (1 kg = 1000 g). A system is not a countable quantity and thus is not a number. The SI symbol ''m'' is used to indicate the mass of a system [kg], whereas the symbol ''M'' is used to indicate the mass of an individual (object) [kg·x<sup>-1</sup>]. Both, body mass [kg/x] and mass of a | + | |description=The '''body mass''', ''M'', is the mass [kg] of an individual (object) [x] and is expressed in units [kg/x]. The individual (object) is a countable quantity, therefore, the unit [x] is a dimensionless number. The SI unit for mass (of a system), ''m'', is [kg] (1 kg = 1000 g). A system is not a countable quantity and thus is not a number. The SI symbol ''m'' is used to indicate the mass of a system or sample [kg], whereas the symbol ''M'' is used to indicate the mass of an individual (object) [kg·x<sup>-1</sup>]. Both, body mass [kg/x] and mass of a sample [kg] are [[Extensive quantity |extensive quantities]], which depend on the size of the individual or the sample. Whereas the body weight changes as a function of gravitational force (you are weightless at zero gravity; your floating weight in water is different from your weight in air), your mass is independent of gravitational force, and it is the same in air and water. |
− | The total body mass is the sum of lean body mass and fat mass, ''M'' = ''M''<sub>L</sub> + ''M''<sub>F</sub>, or the sum of the reference body mass of the [[healthy reference population]] and excess body mass, ''M'' = ''M''° + ''M''<sub>E</sub>. The excess body mass, in turn, is the sum of excess lean and [[Body fat excess |fat mass]], ''M''<sub>E</sub> = ''M''<sub>LE</sub> + ''M''<sub>FE</sub>. The [[body mass excess]], BME, is normalized for the reference body mass, BME = ''M''/''M''°. | + | The total body mass is the sum of lean body mass and fat mass, ''M'' = ''M''<sub>L</sub> + ''M''<sub>F</sub>, or the sum of the reference body mass of an individual at a given height in the [[healthy reference population]] and excess body mass, ''M'' = ''M''° + ''M''<sub>E</sub>. The excess body mass, in turn, is the sum of excess lean and [[Body fat excess |fat mass]], ''M''<sub>E</sub> = ''M''<sub>LE</sub> + ''M''<sub>FE</sub>. The [[body mass excess]], BME, is normalized for the reference body mass, BME = ''M''/''M''°. |
|info=[[Gnaiger 2019 MitoFit Preprint Arch]], [[Gnaiger 2019 MiP2019]] | |info=[[Gnaiger 2019 MitoFit Preprint Arch]], [[Gnaiger 2019 MiP2019]] | ||
}} | }} | ||
− | Contributed by [[Gnaiger E]] (2020-01- | + | Contributed by [[Gnaiger E]] (2020-01-16) |
+ | == Body mass and body tissue mass versus mass of a tissue sample == | ||
+ | :::# The body mass, ''M'', is the mass, ''m'' [kg], per individual, ''N''=1 [x]. Accepting to write the unit for the countable number of objects [x] explicitly, then the unit of ''M'' = ''m''/''N'' is [kg/x]. The average body mass of a population can be obtained theoretically in two ways: (''1'') ''M'' can be measured for each individual of a large sample and expressed as the average of ''N'' measurements. (''2'') The total mass, ''m'' [kg], of ''N'' [x] individual objects can be obtained in a single measurement, and the average body mass per individual is then calculated as ''M'' = ''m''/''N'' [kg/x]. Of course, the second approach is not practical for humans, but is typical for cultured cells or small animals, such as nematodes. It is suggested to use the upper case letter ''M'' as the symbol for the quantity mass per object. | ||
+ | :::# The mass of a tissue (''e.g.'', muscle or fat) is of interest in two contexts: (''1'') The tissue (muscle, M) mass obtained from a biopsy, ''m''<sub>M</sub> [kg] or [mg] of wet or dry tissue mass; and (''2'') the total muscle or fat mass per individual object, ''M''<sub>M</sub> or ''M''<sub>F</sub> [kg/x]. | ||
+ | |||
== Human body mass == | == Human body mass == | ||
:::: The body mass of a human is measured without outdoor clothing (in light underware or swimsiut and without shoes) standing upright on a firm horizontally leveled and calibrated balance. This SOP applies to mobile persons who can stand steadily for the measurement. Some studies apply rigorous standards: 'All measurements were done at least 3 h after a meal (including drink), and subjects were requested to refrain from strenuous exercise 12 h prior to the measurements. Subjects were asked to empty their bladder before the measurements. Females were not measured during their menstrual period' ([[Deurenberg 2001 Eur J Clin Nutr]]). | :::: The body mass of a human is measured without outdoor clothing (in light underware or swimsiut and without shoes) standing upright on a firm horizontally leveled and calibrated balance. This SOP applies to mobile persons who can stand steadily for the measurement. Some studies apply rigorous standards: 'All measurements were done at least 3 h after a meal (including drink), and subjects were requested to refrain from strenuous exercise 12 h prior to the measurements. Subjects were asked to empty their bladder before the measurements. Females were not measured during their menstrual period' ([[Deurenberg 2001 Eur J Clin Nutr]]). |
Revision as of 10:59, 16 January 2020
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Body mass
Description
The body mass, M, is the mass [kg] of an individual (object) [x] and is expressed in units [kg/x]. The individual (object) is a countable quantity, therefore, the unit [x] is a dimensionless number. The SI unit for mass (of a system), m, is [kg] (1 kg = 1000 g). A system is not a countable quantity and thus is not a number. The SI symbol m is used to indicate the mass of a system or sample [kg], whereas the symbol M is used to indicate the mass of an individual (object) [kg·x^{-1}]. Both, body mass [kg/x] and mass of a sample [kg] are extensive quantities, which depend on the size of the individual or the sample. Whereas the body weight changes as a function of gravitational force (you are weightless at zero gravity; your floating weight in water is different from your weight in air), your mass is independent of gravitational force, and it is the same in air and water. The total body mass is the sum of lean body mass and fat mass, M = M_{L} + M_{F}, or the sum of the reference body mass of an individual at a given height in the healthy reference population and excess body mass, M = M° + M_{E}. The excess body mass, in turn, is the sum of excess lean and fat mass, M_{E} = M_{LE} + M_{FE}. The body mass excess, BME, is normalized for the reference body mass, BME = M/M°.
Abbreviation: M [kg·x^{-1}]
Reference: Gnaiger 2019 MitoFit Preprint Arch, Gnaiger 2019 MiP2019
Contributed by Gnaiger E (2020-01-16)
Body mass and body tissue mass versus mass of a tissue sample
- The body mass, M, is the mass, m [kg], per individual, N=1 [x]. Accepting to write the unit for the countable number of objects [x] explicitly, then the unit of M = m/N is [kg/x]. The average body mass of a population can be obtained theoretically in two ways: (1) M can be measured for each individual of a large sample and expressed as the average of N measurements. (2) The total mass, m [kg], of N [x] individual objects can be obtained in a single measurement, and the average body mass per individual is then calculated as M = m/N [kg/x]. Of course, the second approach is not practical for humans, but is typical for cultured cells or small animals, such as nematodes. It is suggested to use the upper case letter M as the symbol for the quantity mass per object.
- The mass of a tissue (e.g., muscle or fat) is of interest in two contexts: (1) The tissue (muscle, M) mass obtained from a biopsy, m_{M} [kg] or [mg] of wet or dry tissue mass; and (2) the total muscle or fat mass per individual object, M_{M} or M_{F} [kg/x].
Human body mass
- The body mass of a human is measured without outdoor clothing (in light underware or swimsiut and without shoes) standing upright on a firm horizontally leveled and calibrated balance. This SOP applies to mobile persons who can stand steadily for the measurement. Some studies apply rigorous standards: 'All measurements were done at least 3 h after a meal (including drink), and subjects were requested to refrain from strenuous exercise 12 h prior to the measurements. Subjects were asked to empty their bladder before the measurements. Females were not measured during their menstrual period' (Deurenberg 2001 Eur J Clin Nutr).
Self-reported measurements
- 'Men overestimated their height by 1.3 to 1.9 cm and the women by 0.5 to 1.3 cm. Men overestimated their weight by up to 0.45 kg and women underestimated their weight by up to 1.4 kg' (Tipton 2012 Nursing).
MitoPedia: BME
MitoPedia: BME
Term | Abbreviation | Description |
---|---|---|
BME and mitObesity | ||
BME cutoff points | BME cutoff | Cutoff points for body mass excess, BME cutoff points, define the critical values for underweight, overweight, obesity and various degrees of obesity. BME cutoffs are calibrated by crossover-points of BME with established BMI cutoffs. The underweight and severe underweight cutoff points are BME = -0.1 and -0.2. The overweight cutoff is BME = 0.2. Increasing degrees of obesity are defined by BME cutoffs of 0.4, 0.6, 0.8, and above. |
Body fat excess | BFE | Body fat is conventionally expressed as BF%, which is the percentage of body fat mass relative to the total body mass. In the healthy reference population (HRP), there is zero body fat excess, and the fraction of excess body fat in the HRP is expressed - by definition - relative to the reference body mass, M°, at any given height. Although M° is identical in females and males at any given height, the fraction of body fat is higher in females than males in the HRP, hence it is reasonable that the body fat excess, BFE, - but not BF% - represents the common risk factor and indicator of obesity. Importantly, body fat excess and body mass excess, BME, are linearly related, which is not the case for the body mass index, BMI. |
Body mass | M [kg·x^{-1}] | The body mass, M, is the mass [kg] of an individual (object) [x] and is expressed in units [kg/x]. The SI unit for mass (of a system), m, is [kg] (1 kg = 1000 g). The individual (object) is a countable quantity, therefore, the unit [x] is a dimensionless number. Whereas the body weight changes as a function of gravitational force (you are weightless at zero gravity; your floating weight in water is different from your weight in air), your mass is independent of gravitational force, and it is the same in air and water. |
Body mass excess | BME | The body mass excess, BME, is an index of obesity and as such BME is a lifestyle metric. The BME with respect to the healthy reference population, HRP, is defined as BME ≝ ΔM/M°. ΔM is the excess body mass exceeding the reference body mass, M°, in the HRP. Thus the BME is a measure of the extent to which your actual body mass, M [kg/x], deviates from M° [kg/x], which is the reference body mass [kg] per individual [x] without excess body fat. The BME is expressed relative to the reference body mass for your height, H [m]. A balanced BME is BME° = 0.0 with a band width of -0.1 towards underweight and +0.2 towards overweight. |
Gnaiger 2019 MiP2019 | ||
Healthy reference population | HRP | A healthy reference population, HRP, of zero underweight or overweight is considered as a standard population. The WHO Child Growth Standards on height and body mass refer to healthy girls and boys from Brazil, Ghana, India, Norway, Oman and the USA. The Committee on Biological Handbooks compiled data on height and body mass of healthy males from infancy to old age (USA), published before emergence of the fast-food and soft drink epidemic. Four allometric phases are distinguished with different allometric exponents. At heights above 1.26 m the allometric exponent is 2.9, equal in women and men, and significantly different from the BMI [kg/m^{2}] exponent of 2. |
Height of humans | H [m] | The height of humans, H, is given in SI units in meters [m]. Without further identifyer, H is considered as the standing height, measured without shoes, hair ornaments and heavy outer garments. |
VO2max | V_{O2max}; V_{O2max/M} | Maximum oxygen consumption, V_{O2max}, is measured by spiroergometry on human and animal organisms capable of controlled physical exercise performance on a treadmill or cycle ergometer. V_{O2max} is the maximum respiration of an organism, expressed as the volume of O_{2} at STPD consumed per unit of time per individual object [mL.min^{-1}.x^{-1}]. If normalized per body mass of the individual object, M [kg.x^{-1}], mass specific maximum oxygen consumption, V_{O2max/M}, is expressed in units [mL.min^{-1}.kg^{-1}]. |
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