body index norm. Why is underweight dangerous: complications. What is your body mass index, determined by an online calculator

The same number on the scale can have different meanings. 80 kg with a height of 190 cm is the norm. But the same 80 kg at 160 cm is already too much, especially for a woman. So it’s not enough to focus on kilograms alone. Ideally, you need to take into account the height, gender, age and lifestyle of a person. In this regard, to determine the norm and pathologies, they use such a concept as BMI.

What it is

BMI is short for body mass index. In English, it sounds like the Body Mass Index (BMI). This is a parameter that reflects the degree of correspondence between the weight and height of a person. It allows you to objectively assess whether he has extra pounds, whether he suffers from exhaustion, or whether everything is normal with him. Most often used in two cases.

Secondly, BMI calculation is necessary in order to control your figure, correct it and, in case of deviation from the norm, take appropriate measures.

Common Formula

Now the BMI formula is officially used, developed back in the middle of the 19th century by Adolf Quetelet, a sociologist and statistician from Belgium. It takes into account only two parameters - height and weight, which does not make it ideal for identifying extra or missing kilograms to the norm. Nevertheless, it has been used in medicine for many decades.

The formula for calculating Quetelet looks like this:

• m (weight) = 80 kg;
• h (height) = 1.6 m;
• we square the meters: 1.6 x 1.6 \u003d 2.56;
• I \u003d 80 / 2.56 \u003d 31.25.

This completes the calculation of the body mass index: it is 31.25. We remember this figure and compare it with normal indicators, according to the table below.

Norm and deviations

The WHO official website has a special table that shows both the BMI norm and deviations. We are looking for which category we fell into with our I \u003d 31.25.

We didn’t get into the normal body mass index, and the table shows not just extra pounds, but first degree obesity (an overview of obesity classifications can be found).

So it’s not at all difficult to calculate BMI and compare the data obtained with the norm. The problem is that the formula is already outdated, and the table from WHO does not reflect all the factors. And this means that the results may not be entirely correct.

For adults

Since weight is influenced by gender and age factors, tables have appeared according to which you can see the norm and deviations from it separately for women and for men, and even taking into account age. According to experts, here the data is more accurate and correct.

For men according to age

For women according to age

Depending only on gender

Depending only on age

Anything below normal is underweight. So, you need to urgently gain the missing kilograms. If the result exceeds the parameter indicated in the table by 5 units, you are overweight. If the difference is more than 5, you should seek qualified help, as we are talking about, most likely.

For children

To calculate BMI for children, you will need the same formula, but the table, accordingly, will be different. In a child, metabolic processes proceed much faster, and energy costs are several times higher than in adults. Therefore, it is imperative to use other standards.

For boys

For girls

Jumps from 7 to 9 years old are explained by the preparation of the body for adolescence and puberty.

Regular determination of BMI in a child allows parents to control his weight and timely prevent both exhaustion and the appearance of extra pounds (read about the features of childhood obesity).

Ideal weight calculation

You can find out your ideal body weight using various formulas that use different parameters for calculations.

General designation (R - height):

• Borngart index: R in centimeters x (multiply) by chest circumference in centimeters / (divide) by 240;
• Breitman index: R in centimeters x 0.7 - 50 kg;
• Brock-Brukst index: for women R in centimeters - 100 - (R in centimeters - 100) / 10; for men, R in centimeters - 100 - (R in centimeters - 100) / 20;
• Davenport index: weight in grams / R in centimeters squared;
• Korovin index: you need to measure the thickness of the skin fold near the 3rd rib (normal 1-1.5 cm) and at the level of the navel (normal 1.5-2 cm);
• Noorden index: R in centimeters x 420/1000;
• Tatonya index: R in centimeters - (100 + (R in centimeters - 100) / 20).

There is also a small addition to the Brock-Bruksta formula: after the result obtained, you need to measure the volume of the wrist, and if it is less than 15 cm, subtract 10% from the ideal weight; at 15–18 cm we do not change anything, if more than 18, we increase the ideal weight obtained by the formula by 10%.

Using any formula, calculating your ideal body weight is easy. The main thing is to draw objective conclusions after comparing the result with real numbers. If the difference in both directions (more/less) is more than 5 kg, then there are problems that it is better to start solving immediately.

Important note!

We draw your attention to the fact that in different sources, data on the norm and deviations of BMI for men, women and children, taking into account age, can differ quite noticeably, with the exception of the general table recommended by WHO. The fact is that the parameters are calculated according to different methods and formulas - hence the difference arises within the unit. In this regard, all parents are advised to use the data for children only indicatively and, in case of doubt, be sure to consult a pediatrician without taking any independent measures.

What is body mass index and how to calculate it for women by age is a very popular topic, one might say hackneyed. Slenderness today is actually a synonym for beauty and certainly an integral part of health. Insufficient weight, as well as its excess, negatively affect the work of all organs and systems of the body. But how do you know if your weight is within the normal range? After all, the concept of the norm will be different for people of different sex, constitution, age. The most accurate today is the formula by which the body mass index is calculated. Still calculating your ideal weight using the "height minus 110" formula? This is correct, but not for everyone. After all, this way you do not take into account many important indicators, for example, the type of figure and age. The body mass index helps to calculate the ideal weight much more accurately. Let's figure out what it is.

What is Body Mass Index (BMI)?

Body mass index is an indicator that characterizes the ratio of height and weight. This also takes into account age and gender, which makes it possible to obtain differentiated data for different groups of people.

This indicator is used by doctors to assess the state of the human body - the presence of obesity or dystrophy and their degree. The calculation of BMI is quite simple, it can be done at home. Perhaps it is the result of calculating the BMI that will become your starting point on the path to a normal body weight.

The first BMI formula appeared in the 19th century, its author was the Belgian Adolf Quetelet. In the future, many scientists were engaged in refining the formula, and today the BMI value can be calculated according to Quetelet, Brock, Breitman, Oder, Noorden, etc.

Most often, it is the basic formula that is used, in which the indicator is equal to the ratio of body weight to height squared (height is indicated in meters). For example, a woman with a height of 165 cm and a weight of 50 kg should calculate BMI as follows: BMI \u003d 50 * (1.65 * 1.65). The final value of BMI = 18.36.

After that, you get the finished figure. As a rule, a weight in the range of 19-25 is considered normal, but this is an average indicator. It is not suitable for minors, the elderly and professional athletes. It turns out that just calculating the body mass index for a woman, even taking into account age, is not enough to understand the state of her body. Decoding of indicators is done using special tables.

What does BMI depend on?

Since the only indicators used in the calculation are height and weight, the final result gives only a general idea of ​​\u200b\u200bthe state of the body.

It is quite obvious that the weight of a healthy girl at 20 and a woman at 55 with the same height is rarely equal. This does not mean that one of them “falls out” of normality. No, just to calculate body mass index by age for a woman over 45 years old, the basic formula is used, but a different interpretation of the results. For every 10 years of life (starting from the age of 24), the normal limit increases by 1 unit.

That is, a normal BMI at the age of 19-24 years is 19-24, 25-34 years is 20-25, etc.

In addition, the appearance of a person depends not only on the actual weight, but also on the ratio of the amount of musculoskeletal and adipose tissue. The normal BMI of athletes is much higher than that of untrained people with weakly expressed muscles.

The interpretation of BMI will also depend on the type of figure, which is determined by measuring the girth of the wrist. This is how thin-boned, normo-boned and wide-boned types are distinguished.

Men have more muscle than women, which means that the body mass index will be higher. The difference between men and women is visible at any age, so the calculation results for different sexes are interpreted in separate tables.

Why do you need to know how to calculate body mass index?

Feeling your own fullness or thinness is very subjective, someone considers himself a fat man, being more than slender, and someone does not consider 10-20 kg of fat hanging on his sides to be superfluous. The BMI calculation was created to help you understand how overweight you are and how much your weight fits into the average statistical norm.

In medicine, the calculation of BMI is used to adjust the doses of drugs, and in everyday life - to control body weight.

Of course, we all strive to look good and in the struggle for beauty we often go to extremes. For example, girls often bring themselves to exhaustion by strict diets or a complete refusal to eat because they think they are not slim enough.

The body mass index allows you to understand whether you are within the normal range, and in which direction you should work on yourself - to reduce weight or, conversely, build muscle.

BMI not only helps to determine the presence of problems with weight, but also shows their degree. Depending on how much the BMI indicator deviates from the norm, the types and intensity of the load, as well as an individual diet, are selected.

Lack of weight is also fraught with serious health problems - metabolic disorders, water-salt balance, hormonal disruptions, beriberi, amenorrhea, osteoporosis. Complications due to these diseases can even lead to death, so it is very important to pay close attention to your weight and health.

At the same time, you should not blindly focus only on numbers - always analyze how comfortable you feel in your body, what symptoms or complaints you have. A slight deviation from the norm may be an individual feature of your body. If you are full of energy, feel good and are satisfied with your health, you definitely shouldn’t reshape yourself to please numbers and indicators.

How to calculate body mass index for women based on age?

So, the standard formula for calculating BMI is suitable for young women around the age of 20-40 years.

If you do not want to fool around with squaring and dividing numbers, you can use the ready-made BMI table. The advantage of such tables is that there are different options for men and women, separate tables for athletes, pregnant women and women over the age of 45.

For older women, there is a simplified formula for calculating BMI: height in centimeters minus one hundred. This is how weight is calculated for women of average build.

If your type is asthenic, subtract 10% from the result. For hypersthenics, the result, on the contrary, should be increased by 10%. It is necessary to make accurate measurements of height and weight in the morning on an empty stomach after visiting the restroom.

As a rule, in the morning our weight is less than the “evening” weight by about a kilogram and a half (due to edema and food eaten during the day), and growth in the morning, on the contrary, is a couple of centimeters higher due to the fact that the spine is in a horizontal position during the night “stretches”, the intervertebral cartilages return to their normal state. But in the evening we are tired, the spine is compressed and, accordingly, growth is less.

Regardless of the formula for calculating the weight that you use, if there are serious deviations from the recommended weight, it is urgent to correct the diet - on your own or with the help of a nutritionist.

Weight index or body mass index (BMI) is a parameter that is determined by a special formula. It allows you to assess how much a person’s weight corresponds to his height, whether there are any deviations from the norm. Knowing your BMI is very important, as timely detection of deviations will reduce the risk of developing diseases caused by underweight or overweight.

CALCULATOR FOR CALCULATION

The formula by which BMI can be calculated is the brainchild of the Belgian statistician and sociologist Adolphe Quetelet. He developed it back in 1869, but nutritionists and doctors use it to this day. I must say that the calculator for calculating this formula does not always give the correct readings. This applies to cases where the age of a person, his gender and professional sports are not taken into account. To obtain accurate data, they resort to other methods and calculation formulas. In particular, the Broca index is extremely common, but this method is applicable to persons whose height is 155–170 cm.

This indicator can be calculated as follows: weight (kg) divided by height (m) squared. For example, if a person with a height of 165 cm weighs 85 kg, then his BMI will be 31.2 units, that is, 85: 1.65 * 1.65 = 31.2. In general, the data of the table of the generally accepted international classification of BMI can be divided into three components: underweight, normal and overweight. Each range has several more stages of evaluation and allows you to more accurately evaluate the parameters of the figure. But all calculations for greater reliability should be made taking into account the distribution of body volumes, bone width and some other structural features of the figure.

INDEX RANGES

Having calculated your BMI using the formula, you need to seek help from a special table that contains the following data:

• if the BMI for women is less than 19, and for men it is less than 20, then we can talk about a body weight deficit. If the calculator gave a value of 16 or less, then we are talking about dystrophy and urgent measures must be taken to increase body weight;
• the BMI norm is in the range of 19–24 for the female half of humanity and 20–25 for the male;
• if this indicator is in the range of 24–30 for women and 25–30 for men, then we can talk about some excess body weight;
• with a BMI in the range of 30–40, there are signs of obesity;
• with a BMI above 40, they are diagnosed with "severe obesity", which can be dangerous to health.

NUANCES OF CALCULATION

Studies by Israeli scientists have shown that for men, the BMI norm lies in the range of 25–27. The conclusion was made based on the fact that it was precisely such characteristics of the physique and figure that were observed in the strong half of humanity with the maximum life expectancy.

For professional athletes who have well-developed muscles, the indicators should be adjusted taking into account their professional activities. If we decipher their BMI according to a common plate, then there will be obesity of the last degree, because the muscle mass of athletes is much larger and heavier than the muscles of an ordinary person.

Due to the fact that it gives a result with some error, you can additionally double-check your parameters using other formulas, for example, calculate them using Broca's formula. According to his calculation method, it is necessary to subtract the number 100 from a person’s height in centimeters. From the total amount obtained, it is necessary to subtract 10% for men and 15% for women. The resulting figure is the norm of a person's weight in kilograms.

You can also check your weight using the Breitman index. The norm is calculated as follows: height in centimeters must be multiplied by 0.7 and subtract 50 from the result obtained. This will be the ideal weight.

The Borngardt Calculator calculates the norm of body weight, taking into account the indicator of the volume of the circumference of the chest. According to this formula, height in centimeters must be multiplied by the volume of the chest in centimeters and divided by 240.

It is necessary to take any measures to change the situation only after consulting a doctor.

Whatever data the calculator gives you, it is not recommended to arbitrarily prescribe a diet for yourself and take any. You need to adjust the weight in time so that later you don’t have to deal with ailments that often go hand in hand with obesity - diabetes, heart and vascular diseases, varicose veins, thrombosis, shortness of breath, excessive sweating, etc.

Imagine a picture: wake up in the morning, take a shower, have breakfast. And when the time comes to put on your favorite jeans, we realize with horror that we can’t fasten them - the stomach interferes. We climb under the sofa, find dusty floor scales, get up on them and ... A familiar story, right?

Whatever figure is displayed on the scales, frustration and depression are received - jeans are not to be worn now. What to do? You can just score. Throw your pants in the trash or shove them into the farthest corner of the chest of drawers - let them lie there until better times. And you can go the other way - throw off a couple of other extra pounds - maybe the trousers will fit.

The second option is more difficult - you need to do something, spend time, make efforts. However, we clench our will into a fist and decide to lose weight. But before starting, another question arises - what to strive for, how many kilograms you need to lose in order to be completely good: both pants to fit in and breathe easier, and to the beach so that in the summer it would not be a shame to get out. We are thinking, trying to figure it out - how to calculate your ideal weight?

It turns out that the ideal (correct) weight is an abstract concept, and it denotes an average value obtained on the basis of a set of given physiological parameters of a person, such as height, age, gender, and body type. But the state of health, the level of physical activity, the percentage of fat mass in relation to muscle mass and other individual indicators of a single person are not taken into account here.

This means that it will not be possible to find the exact value of your weight using known formulas. However, we will get an approximate guideline that we can rely on when reducing or gaining body weight.

The most famous types of weight calculation by formulas:

• Calculation of weight by height
• Calculation of weight by age and height
• Calculation of weight by BMI (body mass index)

Calculate weight by height

A simple method known more as Brokk's formula. The simplified version looks like this:

• For women: Ideal weight = Height (cm) - 110
• For men: Ideal weight = Height (cm) - 100

Example: the normal weight of a man with a height of 180 cm is 80 kg, and for a woman with a height of 170 cm - 60 kg

The modern version of the same formula looks a little different, but is considered more accurate:

• For women: Ideal weight = (Height (cm) - 110) * 1.15
• For men: Ideal weight = (Height (cm) - 100) * 1.15

Example: the normal weight of a man with a height of 180 cm is 92 kg, and for a woman with a height of 170 cm - 69 kg

Calculate weight by age and height

The following weight determination method is not a calculation formula. This is a ready-made table with which you can calculate the correct weight by age. And if the previous version gives an approximate norm of a person’s body weight, then the Egorov-Levitsky table, as it is also called, displays the maximum allowable weight value, the excess of which is considered unacceptable for a given height and age group.

All you need to know is your height, age and actual weight. Look for the intersection of these parameters in the table and understand how far you are from the maximum allowable value. If the figure in the table is higher than your existing weight, it’s good, if it’s lower, there is reason to think about the gym and dietary restrictions.

Example: A woman with a height of 170 cm, 35 years old, weight 75 kg. Crossing over the table shows the maximum weight value of 75.8. A woman is one step away from this value. Therefore, close control of body weight is needed, otherwise it is possible to go beyond the permissible limits.

Calculate weight by BMI (Quetelet body mass index)

table for calculating the optimal weight by Quetelet's body mass index

With the help of the Body Mass Index, you can find out in which predetermined range a person’s weight is at the current moment: deficiency, normal or obesity (all BMI values ​​are shown in the table).

BMI is calculated using a formula that uses baseline height in meters and weight in kilograms. The formula looks like this: KMT = weight in kilograms: (height in meters * height in meters).

Example: a man with a height of 185 cm (1.85 m) and a weight of 88 kg will have a BMI \u003d 88: (1.85 * 1.85) \u003d 27.7. We are looking for a value in the table and we understand that the index is in the range of Overweight (pre-obesity).

An important point: the calculation of the correct weight according to BMI does not take into account gender and age-related changes in the body.

Conclusion

It is important to remember, whichever method of calculating the correct weight you choose, the result of the calculations should not be taken as an absolute truth. All figures will be approximate and indicative. And jeans from these calculations still won't fit. So dumbbells in your hands, legs in sneakers, a lock on the refrigerator and forward - towards the result.

The body mass index is a measure of the ratio of a person's weight to height. This parameter helps to determine deviations from normal body weight in one direction or another. Excess weight is dangerous for human health, as it often leads to heart disease. The online body mass index calculator allows you to quickly and accurately find out how your weight indicator corresponds to the norm. To calculate the body mass index, you need to select your height and weight in the presented service.

The body mass index for women is considered normal if the indicator is in the range from 20 to 22. For men, this indicator should be from 23 to 25. Statistics show that people who have this indicator in the range of 18-22 live longer on average than those with weight problems.

If your BMI is over 25, then this is a signal that you need to change your lifestyle. It is important to note that the formula used to calculate the body mass index may overestimate the obesity rate for people of athletic build, since the calculation does not take into account muscle mass.

The body mass index has become especially relevant in Western countries, where the problem of obesity has become quite acute. At the very beginning, the BMI calculation was developed for sociological research, so making a medical diagnosis using these calculations is not entirely correct.
However, the availability and ease of calculation made this calculator very popular among the population. If the index exceeds the number 30, then this most likely indicates obesity.
It must be understood that the body mass index is not suitable for making a diagnosis, but it can help as a control in the process of trying out a new fitness program or diet.
The BMI calculator will give you a starting point and allow you to track changes in body weight.

Formula for calculating body mass index (BMI)

To find out your BMI, you only need to divide your weight in kilograms by the square of your height in meters.

BMI = WEIGHT / HEIGHT 2

The formula does not take into account the sex and age of a person, despite the fact that the BMI of men is higher than the BMI of women, as well as the BMI is higher in middle-aged people, and in children and the elderly this figure is lower.

The formula is not suitable for calculating BMI for children.

Summary table of values

Interpretation of BMI indicators, in accordance with the recommendations of the World Health Organization (WHO)