Not to be confused with Mass Index (technical analysis).
Body mass index(eng. body mass index (BMI), BMI) - a value that allows you to assess the degree of correspondence between a person's mass and his height and thereby indirectly assess whether the mass is insufficient, normal or excessive. It is important in determining the indications for the need for treatment.
Body mass index is calculated by the formula:
,- m- body weight in kilograms
- h- height in meters,
and is measured in kg / m².
For example, a person's weight = 60 kg, height = 170 cm.Consequently, the body mass index in this case is:
BMI = 60: (1.70 x 1.70) = 20.7
The body mass index was developed by the Belgian sociologist and statistician Adolphe Quetelet in 1869.
Interpreting BMI indicators
The body mass index should be used with caution, solely for indicative assessment - for example, an attempt to assess physique using it professional athletes may give an incorrect result (the high value of the index in this case is explained by the developed muscles). Therefore, for a more accurate assessment of the degree of fat accumulation, along with the body mass index, it is advisable to also determine the indices of central obesity.
Taking into account the shortcomings of the method for determining body mass index, a body volume index was developed.
According to an Israeli study, a body mass index of 25-27 is ideal for men. The average life expectancy for men with this BMI was the highest.
In addition, a number of indices can be used to determine normal body weight:
- Broca's index is used with a height of 155-170 cm. The normal body weight is equal to (height [cm] - 100) ± 10%.
- Breitman index. Normal body weight is calculated by the formula - height [cm] 0.7 - 50 kg.
- Bernhard Index. Ideal body weight is calculated by the formula - height [cm] circumference chest[cm] / 240.
- Davenport Index. The mass of a person [g] is divided by the height [cm] squared. An excess of the indicator above 3.0 indicates the presence of obesity (obviously, this is the same BMI, only divided by 10).
- Oder index. Normal body weight is equal to the distance from the crown to the symphysis [cm] 2 - 100.
- Noorden index. Normal weight is equal to height [cm] 420/1000.
- Tatonya index. Normal body weight = height - (100 + (height - 100) / 20)
In clinical practice, the body mass index is most often used to estimate body weight.
In addition to height and weight indicators, the method for determining the thickness can be used skin fold proposed by Korovin. Using this technique, the thickness of the skin fold is determined at the level of 3 ribs (normally - 1.0 - 1.5 cm) and parasagittally at the level of the navel (on the side of the rectus abdominis muscle, normally 1.5 - 2.0 cm).
Disadvantages and limitations
The interpretation of BMI indicators, recommended by WHO, does not take into account the sex and age of a person. Although statistics from many countries show that BMI in men is higher than in women. In addition, BMI is higher in middle-aged people than in young and old people. For example, the following are statistics on anthropometric data on BMI in the United States, compiled by the United States Department of Health:
| Body mass index for males and females aged 20 and above, and percentage distribution by sex and age: USA, 2007-2010. Source: Antropometric Reference Data for Children and Adults: United States from the U.S. Department of Health |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Age | Percentage distribution of population and BMI values on these percentiles | |||||||||
| 5 % | 10 % | 15 % | 25 % | 50 % | 75 % | 85 % | 90 % | 95 % | ||
| BMI in men, kg / m | ||||||||||
| 20.7 | 22.2 | 23.2 | 24.7 | 27.8 | 31.5 | 33.9 | 35.8 | 39.2 | ||
| 20-29 years old | 19.4 | 20.7 | 21.4 | 22.9 | 25.6 | 29.9 | 32.3 | 33.8 | 36.5 | |
| 30-39 years old | 21.0 | 22.4 | 23.3 | 24.9 | 28.1 | 32.0 | 34.1 | 36.2 | 40.5 | |
| 40-49 years old | 21.2 | 22.9 | 24.0 | 25.4 | 28.2 | 31.7 | 34.4 | 36.1 | 39.6 | |
| 50-59 years old | 21.5 | 22.9 | 23.9 | 25.5 | 28.2 | 32.0 | 34.5 | 37.1 | 39.9 | |
| 60-69 years old | 21.3 | 22.7 | 23.8 | 25.3 | 28.8 | 32.5 | 34.7 | 37.0 | 40.0 | |
| 70-79 years old | 21.4 | 22.9 | 23.8 | 25.6 | 28.3 | 31.3 | 33.5 | 35.4 | 37.8 | |
| 80 years and above | 20.7 | 21.8 | 22.8 | 24.4 | 27.0 | 29.6 | 31.3 | 32.7 | 34.5 | |
| Age | BMI in women, kg / m | |||||||||
| 20 years up to 80+ (total on average) | 19.5 | 20.7 | 21.7 | 23.3 | 27.3 | 32.5 | 36.1 | 38.2 | 42.0 | |
| 20-29 years old | 18.8 | 19.9 | 20.6 | 21.7 | 25.3 | 31.5 | 36.0 | 38.0 | 43.9 | |
| 30-39 years old | 19.4 | 20.6 | 21.6 | 23.4 | 27.2 | 32.8 | 36.0 | 38.1 | 41.6 | |
| 40-49 years old | 19.3 | 20.6 | 21.7 | 23.3 | 27.3 | 32.4 | 36.2 | 38.1 | 43.0 | |
| 50-59 years old | 19.7 | 21.3 | 22.1 | 24.0 | 28.3 | 33.5 | 36.4 | 39.3 | 41.8 | |
| 60-69 years old | 20.7 | 21.6 | 23.0 | 24.8 | 28.8 | 33.5 | 36.6 | 38.5 | 41.1 | |
| 70-79 years old | 20.1 | 21.6 | 22.7 | 24.7 | 28.6 | 33.4 | 36.3 | 38.7 | 42.1 | |
| 80 years and above | 19.3 | 20.7 | 22.0 | 23.1 | 26.3 | 29.7 | 31.6 | 32.5 | 35.2 | |
In Russia, too, if we apply the BMI indicators recommended by the WHO, it turns out that more than half of women and men over 30 in Russia are overweight, and about a third are obese, and some are underweight.
By definition from dictionaries, the word "norm" is often understood as "average", but, as can be seen from the statistics above, the so-called "normal" BMI, according to WHO criteria, do not correspond to the standard normal distribution of statistical BMI values among the population. For example, a woman whose BMI is exactly in the middle of the statistical values among the population of her country will be considered “having overweight»In most countries of the world. This discrepancy arose because the recommended BMI indicators were established by the WHO not on the basis of statistical averages, but on the basis of the recommendations of the doctors of this organization.
The definition of "BMI norm" has changed several times over the past 30 years in many countries, so until 1998 in the United States it was considered a normal BMI up to 27.8 kg / m2, but after 1998 the standards were changed, and the BMI recommended by doctors began to end at 25 kg / m2 ... Because of this change in standards, approximately 29 million more Americans are considered overweight and obese.
Correlation between BMI and disease
An increase in BMI positively correlates with an increase in the likelihood of a malignant tumor, in particular adenocarcinoma of the esophagus, and possibly adenocarcinoma of the cardia. There is also a known positive correlation between BMI and GERD.
Researchers from the United States have calculated the value of BMI (body mass index), which guarantees a longer life expectancy. In 1995, scientists selected 400,000 Americans from 50 to 71 years old. For all subjects, the main factors that increase the risk of death were tested: age, alcohol consumption, marital status, educational level, smoking, race, and individual BMIs were determined. It turned out that the minimum risk of dying was in those with a BMI close to 26. By 2009, more than a quarter - 112 thousand people - from this sample had died. The researchers concluded that the generally accepted scheme for categorizing patients by BMI is not accurate enough. A more accurate prognosis and appointment must be made based on the personal data of each patient, his lifestyle and habits.
BMI and conscription
In Russia, if at the time of calling BMI young man above or below the established norms, then he is given a one-time deferral of 6 months. During this time, he must be examined at the clinic, where his weight and health are monitored. If serious illnesses and deviations in health are not detected, as well as if the weight does not change, then the young man is called up to the Armed Forces of the Russian Federation. And, for example, in Taiwan, a young man is commissioned, and it does not matter whether it was really obesity or muscle mass, which once again confirms the shortcomings of BMI which were mentioned above.
Ideal weight is an average reference that is calculated based on data about a large number of people. But all people are different. Lifestyle, food culture, nationality and body type all affect the ideal weight. For example, the normal weight of people with a strong physique will be 2-3% higher than that of people with an average. And the norm for thin people is 3-5% less. Therefore, it is not necessary to strive specifically for the ideal weight, which shows weight calculator... It is quite enough if your weight is within the calculated range.
Beyond weight calculator calculates BMI- body mass index (ideal weight), which is widely used to determine the degree of correspondence between body weight and height.
How to calculate your ideal weight (BMI) yourself
BMI = M: P 2, where
M - body weight in kg
P - height in meters
An example of calculating body mass index: M (weight) - 78 kg, P (height) - 1.68 m
BMI = 78: 1.68 2 = 27.6
From the table below, you can see that a BMI of -27.6 corresponds to overweight.
BMI interpretation table
In the event of a strong deviation from the norm, it is just right to seriously think about correcting your weight. With a reduced weight, dystrophy develops. In the modern civilized world, it is usually caused by deliberate malnutrition. Desire to have is unnatural slim figure can turn into a violation of both the psyche and physical health- working capacity decreases, the skin dries up, hair falls out. All this comes from a lack of substances necessary for the body.
However, their excessive excess also does not lead to anything good. A huge number of people suffer from obesity. Being overweight greatly increases the risk of kidney stones and gallbladder, joint deformities, impotence, myocardial infarction and many other diseases. The entire body works with overload, moving fat masses in space that are not provided for by the design of the human body. It is not surprising that the life expectancy of obese people is on average 6-8 years less than the rest.
Body mass index(BMI) is a measure of the correspondence between height and weight of a person, which is designed to identify underweight, normal or overweight. Too much heavy weight is a problem because it can lead to other health problems. To calculate the individual body mass index, it is enough to choose the weight and height in the form below.
It is believed that for women the ideal BMI is from 20 to 22, and for men, as a rule, from 23 to 25. Also, statistics say that people with an indicator from 18 to 22 live longer on average.
If your BMI is above 25, this is not good. However, you should not worry about this, first of all, be happy. Getting depressed due to imperfect body weight is what is not great!
It is also worth noting that this BMI formula overestimates the obesity rate for athletic people, as it does not take into account their muscle mass. It is also not suitable for children.
How to calculate the Body Mass Index using a conventional calculator?
- Enter your weight in the calculator kilograms.
- Twice divide the number by the growth in meters.
- The resulting number will be your Body Mass Index.
What is BMI used for?
Interest in determining the level of obesity grew simultaneously with the development of the problem of obesity in Western countries.
The body mass index was developed more as a tool for mass research than for personal use, and it is not entirely correct to use this indicator as a medical diagnosis, as it sometimes happens.
At the same time, the ease of use of BMI explains such a high popularity of the calculator. An index in the range of 18.5 - 24.9 indicates optimal weight, below 18.5 - an indicator of insufficient body weight, and if it exceeds 30, then this indicates obesity, which carries a health risk.
It is recommended that even with a body mass index of 25, to think about losing weight, especially if the waist is large or there are other risk factors for various diseases (see below). Even a small amount of weight loss (eg 10%) can significantly reduce the risk of developing diseases associated with obesity. If you have excess weight but the waist is not too wide, and there are also fewer than 2 risk factors, then main task becomes not weight loss, but the prevention of further weight gain.
Waist circumference measurement
It is the waist circumference that is an excellent indicator for determining the degree of abdominal obesity, which can lead to hypertension, cardiovascular disease, type 2 diabetes and other complications.
Determining your waist circumference is easy enough - just place the measuring tape horizontally around your waist so that the tape fits snugly around your waist. For men, a waist up to 102 cm is considered the norm, and for women up to 88 cm - a violation of this norm means the risk of developing various complications. It is especially high when a large waist circumference is combined with a high BMI, indicating overweight or one of the degrees of obesity. In addition, the risk exists for those people who have a normal index, but their waist circumference is higher than normal.
Other risk factors for disease
In addition to BMI above 25, large waist circumference, there are other risk factors for disease. These include:
- High blood pressure (hypertension).
- High LDL cholesterol (also called "bad" cholesterol).
- Low HDL cholesterol ("good" cholesterol).
- High triglyceride levels.
- High blood glucose (sugar).
- Family history of heart disease.
- Lack of physical activity.
- Smoking.
What does BMI tell you about your body?
The body mass index is not intended for diagnosis, it rather acts as an average indicator. But if you want to try a new diet or fitness program, then our calculator will help you determine the starting point. If you are characterized by excess weight and some flabbiness of the body, but the index is within the normal range, then you should focus, first of all, on exercise, and wait with the diet for now.
If the goal is to fit into old clothes and lose a few pounds, then diet and exercise are best combined.
When BMI talks about obesity or a condition close to it, then you should stop looking for an excuse for yourself and seriously engage in a diet and fitness program in order to protect your health.
The table characterizing the indicators of body mass index
Ideal body mass index (BMI)
Given the difference in muscle mass between the average man and woman (we do not take into account athletes), the best indicator is:
- 20-22 for women;
- 23-25 for men.
The coefficient (number) of body mass index for men and women is the same, but the program interprets the result differently - you get a calculation depending on your gender.
For example, a man with a BMI of 18 or above has nothing to worry about, but women should not drop their weight to a BMI of 19 or below. So for a man with a BMI of 18.5, the program will inform you that everything is in order, and for a girl with the same body mass index, it will indicate insufficient body weight.
BMI - 18 or less
If you are clearly not eating enough, then you should normalize your diet as soon as possible.
Do you feel like you're eating enough? Then you need to visit a doctor as soon as possible and undergo an examination in order to exclude dangerous diseases.
Body mass index less than 16 is more dangerous for health than 30+.
BMI - 25 or more
Do not be upset and worried about a high body mass index. This indicator is very average and not suitable for everyone. Children and athletes should not be guided by it at all.
It's another matter if the imperfection of your figure is visible to the naked eye. Before starting and dieting, you should definitely consult your doctor. Tests may be needed to make sure that your excess weight is not due to any medical condition.
And only after making sure that there are no contraindications, you can start losing weight.
For those who do not have time to visit the doctor J, we can advise you to minimize the consumption of salty, fried and fatty foods, as well as start doing banal exercises. This alone will seriously reduce the risk of developing cardiovascular diseases and significantly improve general state organism.
How is body mass index calculated?
You can do it yourself. This task will be simplified by a regular calculator. Divide your weight in kilograms by your height in meters twice.
An example for a person with a height of 180 cm and a weight of 75 kg.
- Height 180cm is equal to 1 meter and 80 centimeters, that is, 180cm = 1.8m.
- 75/1,8 = 41,6
- 41,6/1,8 = 23,1
- Body mass index is 23,1
Body mass index and army
A height of less than 150 centimeters or a body weight of less than 45 kg provides the conscript with a reprieve for a period of one year. If, after examination and / or treatment, body weight does not increase, then such a man is exempt from conscription.
The right to a half-year deferral is granted to recruits with a body mass coefficient of less than 18.5 (aged 18-25) and below 19 (for men over 25).
Ideal weight according to the Kreff formula
Calculates your ideal weight based on your age and body type. It is an improved version of Broca's index.
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 affects 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 a norm will be different for people of different sex, constitution, age. The most accurate formula today is considered to be the body mass index. 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, body type 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 a measure of the ratio of height to weight. At the same time, age and gender are also taken into account, which makes it possible to obtain differentiated data for different groups of people.
This indicator is used by doctors to assess the condition 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 the result of calculating BMI will be the starting point for you on your way to normal weight body.
The first BMI formula appeared in the 19th century, its author was the Belgian Adolphe Quetelet. Subsequently, many scientists were engaged in the refinement of the formula, and today the BMI value can be calculated by 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 who is 165 cm tall and weighs 50 kg should calculate the BMI as follows: BMI = 50 * (1.65 * 1.65). The final BMI value = 18.36.
After that, you get the finished figure. As a rule, weight in the range of 19-25 is considered normal, but this is an average figure. It is not suitable for minors, seniors 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. The 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 the state of the body.
It is quite obvious that the weight of a healthy girl at 20 years old and a woman at 55 years old with the same height is rarely equal. This does not mean that any of them “fall out” of the normal range. No, just to calculate BMI for a woman over 45 years old, a 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 is 19-24, 25-34 years - 20-25, etc.
Besides, appearance 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 less muscle mass.
The interpretation of BMI will depend on the body type, which is determined by measuring the girth of the wrist. This is how thin-boned, normosseous and broad-boned types are distinguished.
Men have more muscles than women, which means their body mass index will be higher. The difference between men and women is visible at any age, so the calculation results for different genders are interpreted according to separate tables.
Why do you need to know how to calculate body mass index?
The feeling of one's own fullness or thinness is very subjective, someone considers himself to be a fat man, being more than slender, and someone does not consider 10-20 kg of fat hanging from his sides to be extra. The BMI calculation is designed to help you understand how inclined you are to be overweight and how much your weight fits into the average statistical framework of the 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 often go to extremes in the struggle for beauty. For example, girls often drive themselves to exhaustion by strict diets or complete rejection from food due to the fact that it does not seem to be slim enough.
Body mass index allows you to understand whether you are within normal limits, and in which direction you should work on yourself - to reduce weight or, conversely, to build muscle.
BMI not only helps to determine the presence of weight problems, 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 the individual diet, are selected.
Lack of weight is also fraught with serious health problems - metabolic disorders, water-salt balance, hormonal disruptions, vitamin deficiency, amenorrhea, osteoporosis. Complications due to these diseases can even lead to death, therefore, it is very important to be attentive to your weight and health.
At the same time, blindly focusing only on numbers is not worth it - 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 should definitely not reshape yourself to please the 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 between the ages of 20-40.
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 variants 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 the weight is calculated for women of average build.
If your type is asthenic, subtract 10% from the result obtained. For hypersthenics, the result, on the contrary, should be increased by 10%. It is necessary to make accurate measurements of height and weight on an empty stomach in the morning after visiting the restroom.
As a rule, in the morning our weight is less than "evening" 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 "Stretched", the intervertebral cartilages come to their normal state. But in the evening we are tired, the spine is compressed and, accordingly, growth is less.
Regardless of the weight calculation formula that you use, if there are serious deviations from the recommended weight, it is necessary to urgently correct the diet - on your own or with the help of a nutritionist.