In recent 2 years, the average height of countries around the world has increased by 1 cm every 1 years. There is a trend that the human body is taller from generation to generation. According to records: more than 2 years ago, the average height in the United States was 17 cm, and now it has reached 18 cm, an increase of 1 cm; In the past 3 years, the average height of 14-year-olds in Japan has increased by 8.2 cm; In the 8 years from 1851 to 1931 in Sweden, the height of recruits increased from 166.6 cm to 174.1 cm, an increase of 7.5 cm; The former Soviet Union measured the bones of soldiers in the 18th century and found that the average height of soldiers increased by 2 cm in the past 25 years. In the past 2 years in China, the average height of urban youth aged 18-25 has increased by 2.3 cm for men and 2.15 cm for women.
1. Measuring height
1. Benefits of measuring height
It is generally believed that weight changes rapidly, so the increase or decrease of weight is often used as an objective criterion for evaluating health. In fact, the accuracy of evaluating growth, health and fatigue with height growth is no less than weight.
In childhood and adolescence, measuring the height once or twice a year (preferably once a quarter) is one of the important means to grasp the growth and development in time. Normal height growth indicates good growth and development; If the growth of height is slow, basically not long, or even stops, it is necessary to analyze the reasons and take corresponding measures to make targeted remedies.
Middle-aged and elderly people often measure their height, and to some extent, they can also evaluate the degree of aging. Height decreases with age. Normal people peak at the age of 2-3. From the age of 4, the height decreases by 1-2 cm for every 1 years of age. The average height of male elderly people should be reduced by 2.25\\%, while that of female people should be reduced by 2.5%. It has been reported abroad that from the age of 4 to 9, the height of the human body can drop by 7 ~ 9 cm, and even obvious hunchback appears. This physiological change of human body is commonly known as "aging".
The height change in one day is also one of the important methods to evaluate the physiological load and fatigue. As far as an individual is concerned, he is the tallest when he gets up in the morning and the shortest before going to bed at night. This change in height is directly related to the professional characteristics. Those heavy manual workers and athletes, especially weightlifters, have a more obvious change in height in one day. When they get up in the morning, they are 2 ~ 5 cm higher than before going to bed at night. There are two main reasons for this change: first, the spinal disc is compressed. Intervertebral disc is cartilaginous tissue, and the elastic nucleus pulposus in the middle has cushioning effect, which makes the spine have certain stretching activity. Due to the load on the spine, the elasticity of cartilage between vertebrae is temporarily "weakened" and the spine is shortened. Second, the muscles of the neck, back and chest that maintain the normal physiological curvature of the human spine are gradually tired after a day of loading, and the supporting force of the spine is reduced, the curvature is increased, and the height is correspondingly reduced. The physiological increase or decrease of the spine is only a change in one day. After a night's sleep, the muscles are fully rested, and after fatigue is eliminated, the height is also restored.
2. Methods and requirements for measuring height
1) Measurement method: The measured person stands barefoot on the bottom plate of the height meter in a "stand at attention" posture, and the heel, sacrum and shoulder blades are close to the column of the height meter. The measurer can stand on the left or right of the measured person, adjust his head to the level of the upper edge of the tragus and the lowest point of the lower edge of the orbit, and then move the horizontal plate of the height gauge to the top of the measured person's head, so that the tightness is appropriate, and then the birth height can be measured.
2) measurement requirements: each height measurement should be barefoot, and at the same time (more accurate in the morning), with the same height meter, the body posture should be consistent before and after, and the height meter should be placed on the flat ground and at the root of the wall. It is best to measure the height twice in a row, with an interval of 3 seconds. The results of the two measurements should be roughly the same. The error of the height gauge shall not exceed .5 cm.
3. Methods and requirements for measuring the length of the upper body
1) Measurement method: The measured person sits on the seat plate of the height sitting height meter, and the pillow part of the head, the ridge part between the two shoulder blades and the sacrum part should be attached to the upright post of the height sitting height meter. When sitting, the head is straight, the eyes are straight, the trunk is straight, the legs are close together, the angle between the big leg and the small leg is kept at 9 degrees, the feet are placed on the ground or the pad of the height gauge, and the arms naturally hang down to the side. The position and operation of the surveyor are the same as the height measurement.
2) measurement requirements: the pillow, the ridge between the two shoulder blades and the sacrum of the head to be measured should be attached to the upright post of the height meter. The rest are the same as height measurement.
4. Methods and requirements for measuring the length of lower limbs
1) Measurement method: The measured person's feet are shoulder-width apart and stand on a flat ground. Measure the vertical distance from the upper edge of the femoral trochanter of the left lower limb to the ground, which is the length of the lower limb.
2) measurement requirements: the surveyor must accurately touch the upper edge of the greater trochanter bone of the measured person. When touching, first stick the index finger, middle finger and ring finger on the trochanteric bone of the measured person, let the measured person bend his knees and lift his thigh, and then swing his straight leg back and forth several times, so that the measuring person can accurately judge the upper edge position of the trochanteric bone (where the upper end of the femur rotates with the action). The error of steel tape measure shall not exceed .2 cm.
Ordinary families don't have a height gauge, so they can straighten and fix it on the door with a small tape measure, and replace the horizontal plate of the height gauge with a book, and measure it according to the operation method, which can also accurately measure the height.
As mentioned earlier, height depends on two factors: heredity and acquired environment. Of these two factors, heredity plays an extremely important role, but the positive role of acquired environmental factors, especially in the two key periods of growth and height, in ensuring adequate and balanced nutrition and regular physical exercise cannot be underestimated.
Many people want to be tall, and some young women pay special attention to men's height when looking for a partner. Once upon a time, there was a joke in the society that compared young men of medium height to "disabled". It is not proper to emphasize height unilaterally in mate selection. Tall people have advantages, and short people also have their advantages. Comparing the two groups, short people are smarter, smarter, healthier and live longer than tall people. Chinese medical experts have investigated Hunan, Hubei, Guangxi, Guizhou and other provinces and regions, and found that the height of the elderly over 9 years old is mostly between 128 and 158 cm, and their weight is about 4 kg. American scholar Marlowe surveyed celebrities and athletes from all walks of life in the United States with a height of 173 cm as the boundary. As a result, 11% of short people lived nine years longer than tall people. Of the 75 men, 13 were short among the 15 who lived over 9. Among the nine celebrities who have lived over 9 years and achieved success, 8 are short. Giants over 23 cm lived only 39.8 years on average. The average short man lived 8.2 years and the average tall man only lived 66.6 years.
The trend that the height of human beings is higher from generation to generation will continue. Take China as an example. At present, the average height of men in China is 17.3 cm and that of women is 159 cm. It is predicted that in one hundred years, the average height of men and women in China will exceed 183 cm and 169 cm respectively. To this end, some scientists believe that in the future, we may control the continuous increase of human beings as we control population growth today.
so how much is the ideal height? With the development of science and technology, people expect that height growth and height control will become a reality. If so, mankind will be happier.
2. Factors affecting height
Height and weight indicators not only reflect the growth and development of children and adolescents, but also coincide with the development of various tissues and organs of the body. Height is the length and proportion of the longitudinal parts of the human body, which originated from the longitudinal growth of the human body and is greatly influenced by genetic factors. Men are 2 ~ 24 years old, and women are 19 ~ 23 years old. The long bones and vertebrae of the limbs have been ossified, and the height has stopped growing.
There are many factors that affect height, such as heredity, nutrition, sports, environment, living habits, race, endocrine, sexual maturity sooner or later (the average age of menarche is 5 cm higher than that of 11 years old), marriage between distant relatives, medical progress and so on.
1. Heredity
Growth and development are influenced by congenital heredity, acquired nutrition, physical exercise and various living conditions. But among many factors affecting height, heredity is more important. The human body develops from a single-celled fertilized egg to a complex multicellular individual, and from a young fetus to a strong individual, all of which are controlled by genetic genes. The heritability of body length is as high as .75 ~ .92, especially for daughters, with heritability as high as .85 ~ .92. That is to say, the height of men is 75% ~ 92%, and that of women is 85% ~ 92%, which is influenced by genetic variation. Only 25% for men and 15% for women depend on other factors. It is proved that heredity plays an extremely important role in children's height. Relatively speaking, weight is less affected by genetic genes, with 63% of males and 42% of females being affected by genetic factors. 37% of men and 58% of women depend on acquired environmental factors. It can be seen that the acquired environment has a great influence on body weight.
2. Nutrition
Nutrition is an indispensable material basis for human beings to survive, that is, to maintain normal life, develop their bodies and engage in activities. Especially in the peak period of human growth and development, it is very important to ensure the supply of high quality and sufficient nutrition and balance vitamins and minerals (calcium, phosphorus, zinc, etc.). The average height of urban children and adolescents in China is 2 ~ 4 cm higher than that in rural areas. One of the reasons is that urban nutrition is better than that in rural areas. Take protein as an example, the nutrition of height is especially "piled up" by protein. It is known that there are about 2 kinds of amino acids in human body or nature, and the amino acids that make up protein depend on nutrition. Food can provide enough 8 essential amino acids, which is beneficial to accelerate the synthesis of protein, thus promoting the growth and development of human tissues and organs, especially the growth and development of bones and epiphyseal cartilage. Taking lysine as an example, six pairs of twins in Japan were divided into two groups. The first group was given normal nutrition, and the second group was added lysine to the normal nutrition. After 13,2 hours of the experiment, it was found that the second group was 1.7 cm taller and weighed 1 kg more than the first group. Experiments on school-age children show that the height and weight of the experimental group added with .5 g lysine per meal are significantly higher than those of other school-age children. In some countries, 25 grams of soybean flour and appropriate amounts of calcium, iron and vitamins are added to children and adolescents' lunch bread. After half a year, these children and adolescents are 2.62 kilograms heavier, .9 centimeters taller and 3.4 grams higher in hemoglobin than children and adolescents who eat ordinary diet. The reason is that protein is not only a "building material" of human body, but also an important substance of enzymes, hormones, hemoglobin, fibronectin and collagen which participate in important physiological activities of human body. Similarly, the nutritional status of the mother also restricts the normal development of the fetus to a certain extent. If there is a lack of certain nutrients in the diet, it will cause fetal malformation.
Malnutrition will not only affect the growth and development, but also affect the quantity and quality of brain cells. On the contrary, overnutrition will lead to obesity, which is also harmful to the physical and mental health of children and adolescents.
3. Sports
Among many acquired factors that affect height, the most positive and effective factor is sports. What affects the physical development of children and adolescents is muscular weakness. Doing more exercise is a physiological need for children and teenagers to grow taller. Therefore, sports is an important driving force for the healthy growth of children and adolescents. A large number of survey data at home and abroad have proved that the chest circumference, vital capacity and grip strength of children and adolescents who insist on exercise are increased by 5 ~ 8 cm, 5 ~ 15 ml and 4.6 ~ 5.7 kg respectively compared with children and adolescents of the same age who do not exercise or lack exercise. Insisting on exercise is helpful to the growth and development of children and adolescents. According to the survey data of a primary school in Liaoning, the students who often participate in the training of schools or sports schools are 4 cm taller, 2 kg heavier and 2 ml more vital capacity than ordinary students. In the extreme night without sunlight, children in the far north of the former Soviet Union have low activity enthusiasm. Although they are tall and have a large skeleton, they have poor physical strength and endurance. Compared with children in the south of the same age, their grip strength is 8 kg less, their long jump performance is 9 cm less, and their high jump performance is 3 cm less. All these prove that physical exercise can not only promote height, but also affect the improvement of physical function and sports ability.
4. Environment
Environment includes natural environment, social environment and psychological environment. Environment also affects human growth and development to varying degrees. Take the influence of natural environment (the sum of various natural factors around human beings in human ecosystem), climate conditions and geographical environment on height as an example. Generally speaking, children and adolescents in tropical and temperate regions have earlier sexual maturity and slightly lower physical development level. After a survey conducted by the Institute of Pediatrics of China Academy of Sciences in 1975, the average height (cm) of the 17-year-old group was analyzed: male, Beijing 168.7, Wuhan 167.8 and Guangzhou 164.7; Female, Beijing 157.7, Wuhan 157.3, Guangzhou 155.3. From the investigation on the body shape, physiological function and physical quality of children and adolescents in China in 1982, it is proved that children and adolescents aged 7-17 in Beijing are 2.5-4.6 cm taller than those of the same age group in Hunan. The above two surveys prove that the height of children and adolescents in China tends to be higher in the north and lower in the south. This trend is not only related to food varieties, but also directly related to climate, geographical location, lighting time and other factors.
psychological factors can also affect growth and development. Psychological factors can be said to be the sum of emotions, and seven emotions, such as joy, anger, sadness, joy, sadness, fear and shock, are the expression of emotions. The emotional world is varied, and the objective things give the human body the feeling of happiness, cheerfulness, happiness or sadness, pain and disappointment, which directly affects all human activities. Sudden, intense and lasting emotional stimulation will affect the activities of viscera, qi and blood, brain and endocrine system of human body. Sadness, depression, sulking, etc. can easily make children and adolescents suffer from various diseases and affect their growth and development. Clinical observation has proved that children who have been seriously stimulated are not only prone to various diseases, but also have slow growth and even stagnation, resulting in premature aging. This is the result of bad psychological factors affecting the function of brain and endocrine. Therefore, to create a good psychological environment for children and adolescents, especially families should give their children warmth, love and care under the premise of positive inspiration and guidance, so that they can get necessary and normal psychological satisfaction, be full of spirit, be happy and grow up healthily.
5. Living habits
Living habits cover a wide range, such as diet, exercise, hygiene, sleep, work and rest system, and the combination of work and rest. Improving some living habits also helps to grow taller. According to relevant data, the average height of Japanese nationals increased by 2.23 cm during the 34 years from 1892 to 1926. The main reason is that in the past, most people had the habit of sitting cross-legged. With the progress of the times, sitting cross-legged was gradually replaced by sitting in a chair, which promoted the growth of lower limb bones for education. Body posture also affects height. When the human body enters the second peak period of growth and development (sudden increase of youth development), the muscle growth rate lags far behind the growth of height, so the muscle fiber is thin, small in cross section and volume, and the muscle strength is poor. Some children and adolescents do not pay much attention to the correct posture of standing, sitting, walking, reading and writing in their daily lives. They always habitually bow their heads, shoulder-end, chest-holding and hunchback, resulting in the deformation of the spine, which will affect the height of 1 ~ 5 cm.
In addition, medical progress can also promote