The value that allows you to evaluate the correspondence of human height and weight is called the body mass index. This assessment makes it possible to approximately determine whether the weight meets the established standards or is deviated up or down. Accurate mass index readings are important for prescribing treatments for diseases such as obesity and anorexia. Therefore, sometimes knowing how to measure your body mass index yourself is vital.
Body mass index: how to measure it
How to measure body mass index? Using a formula developed by the mathematician, sociologist, astronomer, statistician and meteorologist Adolphe Quetelet back in 1869. So, the formula itself is:
I=m/h ², where:
- m - mass, measured in kg;
- h - height, measured in m.
Let's say body weight 75 kg and height 165 cm,so the index will be:
75 ÷ (1.65 × 1.65)=27.55
General performance standards
Compliance with weight and height:
- Mass index less than 16 kg/m² indicates underweight.
- From 16 to 18.5 kg/m² - shortfall in body weight.
- From 18.5 to 24.99 kg/m² - normal weight.
- From 25-30 kg/m² - overweight, underweight.
- From 30-35 kg/m² ―diagnosis of obesity.
- From 35 to 40 kg / m² - pronounced obesity.
- More than 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 age of the person, so it's just a rough estimate.
What is the difference in the measurement of 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 the definition of the limits of normative indications. It varies by 1-2 units.
This is due to the fact that the standard muscles of the male half of humanity more than the female. This is quite a physiological difference.
Norms for Women's Mass Index
So how to measure body mass index for women? We use the standard Quetelet formula "I \u003d m / h ²" and look at our evaluation result:
- If the reading is less than 19 - underweight.
- 19 to 24 kg/m² ―norm.
- 25 to 30 kg/m² is overweight.
- From 31 to 40 kg / m² - the diagnosis of obesity.
- More than 40 kg/m² - very severely obese.
Male BMI Index
How to measure body mass index for men and find out the results? To begin with, BMI is calculated according to the general formula for men and women: I \u003d m / h ². And then correlate your result and its average score:
- Index readings less than 20 kg/m² indicate 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 - 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 changes with age in both sexes. So the question arises of how to measure the body mass index, taking into account age? As mentioned above, the process of measuring the index is one, and it is calculated according to an unchanged formula. But the interpretation of the results depends on age.
Weight is considered normal in the following cases:
- At the age of 19 to 24, the index is approximately 19-24 kg/m².
- From 25 to 34 years old inclusive, the index is 20-25 kg/m².
- 35 to 44 years old ― 21-26 kg/m².
- 45 to 54 ― 22-27 kg/m².
- From 55 to 64 - index 23-28 kg/m².
- For people over 65 years of age - 24-29 kg/m².
If the index is below the specified norm, then there is a shortage in weight. If above the norm, 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 assumed dry data.
Child Mass Index
Naturally, the presence of muscle mass and weight norms in children and adults are completely different, especially for babies under one year old. Therefore, for each childhood there are established norms (up to months) that need to be studied. To do this, you need to be aware of how to measure the body mass index in an infant and how to do it for an older child.
Approximate index rates for the first 6 months:
For newborns:
- BMI 10, 1=severe underweight, severe wasting.
- Index 11, 1 - underweight.
- 12, 2 - weight is reduced, but within normal limits.
- 13, 3 is normal.
- 14, 6 - slightly overweight, there is a risk of further weight gain.
- 16, 1 ―overweight.
- 17, 7 - obese.
1 month:
- Body mass index 10.8 kg/m² - severe underweight, significant wasting.
- 12 kg index― underweight.
- 13, 2 kg– weight reduced, but within normal limits.
- 14, 6 kg is the norm.
- 16 kg― slightly overweight, there is a risk of further weight gain.
- 17.5kg―overweight.
- 19, 1 kg― obese.
2 months:
- BMI 11.8 kg/m² - severe underweight, severe wasting.
- 13 kg index― underweight.
- 14, 3 kg– weight reduced, but within normal limits.
- 15, 8kg is normal.
- 17, 3 kg– Slightly overweight, there is a risk of further weight gain.
- 19 kg―overweight.
- 20.7 kg― obese.
3 months:
- BMI 12.4 kg/m² - severe underweight, severe wasting.
- Index 13.6kg―underweight.
- 14, 9 kg– weight reduced, but within normal limits.
- 16, 4 kg is the norm.
- 17, 9 - slightly overweight, there is a risk of further weight gain.
- 19, 7 ―overweight.
- 21, 5 - obese.
4 months:
- BMI 12, 7 - severe underweight, significant wasting.
- Index 13, 9 - underweight.
- 15, 2 - weight is reduced, but within normal limits.
- 16, 7 is normal.
- 18, 3 - slightly overweight, there is a risk of further weight gain.
- 20 ―overweight.
- 22 ― obesity.
5 months:
- BMI 12, 9 - severe underweight, significant wasting.
- Index 14, 1 - underweight.
- 15, 4 - weight is reduced, but within the normal range.
- 16, 8 is normal.
- 18, 4 - slightly overweight, there is a risk of further weight gain.
- 20, 2 ―overweight.
- 22, 2 ―obesity.
Indicative index norms for children from 6 months to a year
6 months:
- BMI 13 kg/m² - severe underweight, significant wasting.
- Index 14, 1 kg/m²― underweight.
- 15, 5 kg/m²― weight reduced, but within normal limits.
- 16, 9 kg/m²― norm.
- 18.5 kg/m²― Slightly overweight, risk of further weight gain.
- 20, 3 kg/m²―overweight.
- 22, 3 kg/m²― obese.
7 months:
- BMI 13 kg/m² - severe underweight, significant wasting.
- Index 14, 2 kg/m²― underweight.
- 15, 5 kg/m²― weight reduced, but within normal limits.
- 16, 9 kg/m²― norm.
- 18.5 kg/m²― Slightly overweight, risk of further weight gain.
- 20, 3 kg/m²―overweight.
- 22, 3 kg/m²― obese.
8 months:
- BMI 13 kg/m² - severe underweight, significant wasting.
- Index 14, 1 kg/m²― underweight.
- 15, 4 kg/m²― weight reduced, but within normal limits.
- 16, 8 kg/m²― norm.
- 18, 4 kg/m²― Slightly overweight, risk of further weight gain.
- 20, 2 kg/m²―overweight.
- 22, 2 kg/m²― obese.
9 months:
- BMI 12.9 kg/m² - severe underweight, severe wasting.
- Index 14, 1 - underweight.
- 15, 3 - weight is reduced, but within the normal range.
- 16, 7 is normal.
- 18, 3 - slightly overweight, there is a risk of further weight gain.
- 20, 1 ―overweight.
- 22, 1 - obese.
10 months:
- BMI 12.9 kg/m² - severe underweight, severe wasting.
- Index 14 - underweight.
- 15, 2 - weight is reduced, but within normal limits.
- 16, 6 is normal.
- 18, 2 - slightly overweight, there is a risk of further weight gain.
- 19, 9 ―overweight.
- 21, 9 - obese.
11 months:
- BMI 12, 8 - severe underweight, significant wasting.
- Index 13, 9 - underweight.
- 15, 1 - weight is reduced, but within normal limits.
- 16, 5 is normal.
- 18 - slightly overweight, there is a risk of further weight gain.
- 19, 8 ―overweight.
- 21, 8 ― obesity.
1 year:
- BMI 12, 7 - severe underweight, significant wasting.
- Index 13, 8 - underweight.
- 15 - Weight is reduced but within normal limits.
- 16, 4 is normal.
- 17, 9 - slightly overweight, there is a risk of further weight gain.
- 19, 6 ―overweight.
- 21, 6 - obese.
Thus, BMI is an excellent tool for keeping the body in excellent shape. This method was developed veryfor a long time, but this does not prevent him from being relevant in the modern world.
