The value that allows us to assess the conformity of human growth and mass is called the body mass index. This assessment makes it possible to roughly determine whether the weight meets established standards or is rejected up or down. Accurate mass index readings are important for prescribing treatments to cure diseases such as obesity and anorexia. Therefore, sometimes knowing yourself how to measure your body mass index is vital.
Body Mass Index: Measurement Method
How to measure body mass index? Using a formula developed by a mathematician, sociologist, astronomer, statistician and meteorologist Adolf Ketle back in 1869. So the formula itself:
I = m / h ², where:
- m is the mass measured in kg;
- h - growth, measured in m.
Suppose a body weight of 75 kg and a height of 165 cm, then the index will be equal to:
75 ÷ (1.65 × 1.65) = 27.55
General ratios
Correspondence of weight and height:
- Mass index less than 16 kg / m² - pronounced lack of weight.
- From 16 to 18.5 kg / m² - a shortage in body weight.
- From 18.5 to 24.99 kg / m² - the weight is normal.
- From 25-30 kg / m² - overweight, obesity.
- From 30-35 kg / m² ― Diagnosis of obesity.
- From 35 to 40 kg / m² - pronounced obesity.
- Over 40 kg / m² is a very severe form of obesity.
However, this method is considered standard, and it does not take into account gender, physical characteristics (for example, if a person is an athlete, then naturally his index will be overestimated due to muscle mass or if a limb is amputated, then the index will be underestimated) and the person’s age, therefore, gives an approximate indicative estimate.
What are the differences in measuring the index by gender
How to measure the mass index of a man or woman? The very formula for calculating the index for both sexes is unchanged. Differences are visible in determining the limits of normative indications. It varies by 1-2 units.
This is due to the fact that the standard muscle in the male half of humanity is greater than the female. This is a completely physiological difference.
Standards for the Women's Mass Index
So how to measure body mass index for women? We use the standard Ketle formula “I = m / h ²” and look at our evaluation result:
- With indications less than 19 - underweight.
- From 19 to 24 kg / m² - the norm.
- From 25 to 30 kg / m² - excess in weight.
- From 31 to 40 kg / m² - the diagnosis of obesity.
- More than 40 kg / m² - very severe obesity.
BMI male index
How to measure body mass index for men and find out its results? To begin with, BMI is calculated by the general formula for men and women: I = m / h ². And then relate your result and its average rating:
- An index reading of less than 20 kg / m² indicates a serious underweight.
- From 20 to 25 kg / m² - the norm in male weight.
- From 26 to 30 kg / m² inclusive - excess, pre-obesity.
- From 32 to 40 kg / m² - the stage of obesity.
- More than 40 kg / m² is the stage of severe, dangerous obesity.
Optimal body index, depending on age
It's no secret that muscle mass in both sexes changes with age. So the question is, how to measure body mass index based on age? As mentioned above, the process of measuring the index itself is one, and it is calculated according to an invariable formula. But the decoding of the results depends on age.
Weight is considered normal in the following cases:
- At the age of 19-24 years, the index is approximately 19-24 kg / m².
- From 25 to 34 years old, inclusive, the index is 20-25 kg / m².
- From 35 to 44 years old - 21-26 kg / m².
- From 45 to 54 - 22-27 kg / m².
- From 55 to 64 - an index of 23-28 kg / m².
- For people over 65 years of age - 24-29 kg / m².
If the index is lower than the specified norm, then there is a shortage in weight. If higher than normal, then this indicates the approach of obesity or its presence.
It turns out that there is no specific formula that will explain how to measure body mass index taking into account age for women and separately for men - these are all supposed dry data.
Children's Mass Index
Naturally, the presence of muscle mass and weight norms in children and adults are completely different, especially for babies up to a year. Therefore, for each child's age, there are established standards (up to months) that need to be studied. To do this, you must be aware of how to measure the body mass index of an infant and how to do this for an older child.
Approximate index rates in the first 6 months:
For newborns:
- Body mass index 10.1 - severe underweight, significant depletion.
- Index 11.1 - deficiency of body weight.
- 12.2 - weight is reduced, but within normal limits.
- 13.3 is the norm.
- 14.6 - the weight is slightly increased, there is a risk of further gain in excess weight.
- 16.1 ― excess body weight.
- 17.7 - obesity.
1 month:
- A body mass index of 10.8 kg / m² is a severe underweight, significant depletion.
- Index 12 kg― body mass deficit.
- 13.2 kg― weight is reduced, but within normal limits.
- 14.6 kg― normal.
- 16 kg― weight slightly increased, there is a risk of further gain in excess weight.
- 17.5 kg ― excess body weight.
- 19.1 kg― obesity.
2 months:
- A body mass index of 11.8 kg / m² is a severe underweight, significant depletion.
- Index 13 kg― body mass deficit.
- 14.3 kg― weight is reduced, but within normal limits.
- 15.8 kg― normal.
- 17.3 kg― weight is slightly increased, there is a risk of further gain in excess weight.
- 19 kg excess body weight.
- 20.7 kg― obesity.
3 months:
- A body mass index of 12.4 kg / m² is a severe underweight, significant depletion.
- Index 13.6 kg― body mass deficit.
- 14.9 kg― weight is reduced, but within normal limits.
- 16.4 kg― normal.
- 17.9 - the weight is slightly increased, there is a risk of further gain in excess weight.
- 19.7 ― excess body weight.
- 21.5 - obesity.
4 months:
- Body mass index 12.7 - severe underweight, significant depletion.
- Index 13.9 - deficiency of body weight.
- 15.2 - weight is reduced, but within normal limits.
- 16.7 is the norm.
- 18.3 - the weight is slightly increased, there is a risk of further gain in excess weight.
- 20 ― excess body weight.
- 22 - obesity.
5 months:
- Body mass index 12.9 - severe underweight, significant depletion.
- Index 14.1 - deficiency of body weight.
- 15.4 - weight is reduced, but within normal limits.
- 16.8 is the norm.
- 18.4 - the weight is slightly increased, there is a risk of further gain in excess weight.
- 20.2 ― excess body weight.
- 22.2 - obesity.
Indicative guideline norms for children from 6 months to a year
6 months:
- Body mass index 13 kg / m² - severe weight deficit, significant depletion.
- Index of 14.1 kg / m² body mass deficit.
- 15.5 kg / m² ― weight is reduced, but within normal limits.
- 16.9 kg / m² ― normal.
- 18.5 kg / m² ― weight is slightly increased, there is a risk of further gain in excess weight.
- 20.3 kg / m² ― excess body weight.
- 22.3 kg / m² ― obesity.
Seven months:
- Body mass index 13 kg / m² - severe weight deficit, significant depletion.
- Index of 14.2 kg / m² ― body mass deficit.
- 15.5 kg / m² ― weight is reduced, but within normal limits.
- 16.9 kg / m² ― normal.
- 18.5 kg / m² ― weight is slightly increased, there is a risk of further gain in excess weight.
- 20.3 kg / m² ― excess body weight.
- 22.3 kg / m² ― obesity.
8 months:
- Body mass index 13 kg / m² - severe weight deficit, significant depletion.
- Index of 14.1 kg / m² body mass deficit.
- 15.4 kg / m² ― weight is reduced, but within normal limits.
- 16.8 kg / m ²― normal.
- 18.4 kg / m² ― weight is slightly increased, there is a risk of further gain in excess weight.
- 20.2 kg / m² ― excess body weight.
- 22.2 kg / m² ― obesity.
9 months:
- A body mass index of 12.9 kg / m² is a severe underweight, significant depletion.
- Index 14.1 - deficiency of body weight.
- 15.3 - weight is reduced, but within normal limits.
- 16.7 is the norm.
- 18.3 - the weight is slightly increased, there is a risk of further gain in excess weight.
- 20.1 ― excess body weight.
- 22.1 - obesity.
10 months:
- A body mass index of 12.9 kg / m² is a severe underweight, significant depletion.
- Index 14 - deficiency of body weight.
- 15.2 - weight is reduced, but within normal limits.
- 16.6 is the norm.
- 18.2 - the weight is slightly increased, there is a risk of further gain in excess weight.
- 19.9 excess body weight.
- 21.9 - obesity.
11 months:
- Body mass index 12.8 - severe underweight, significant depletion.
- Index 13.9 - deficiency of body weight.
- 15.1 - weight is reduced, but within normal limits.
- 16.5 is the norm.
- 18 - the weight is slightly increased, there is a risk of further gain in excess weight.
- 19.8 excess body weight.
- 21.8 - obesity.
1 year:
- Body mass index 12.7 - severe underweight, significant depletion.
- Index 13.8 - deficiency of body weight.
- 15 - weight is reduced, but within normal limits.
- 16.4 is the norm.
- 17.9 - the weight is slightly increased, there is a risk of further gain in excess weight.
- 19.6 ― excess body weight.
- 21.6 - obesity.
Thus, the BMI is an excellent tool to maintain the condition of the body in excellent shape. This method was invented a long time ago, but this does not prevent it from being relevant in the modern world.