Human heightHuman height or stature is the distance from the bottom of dianabol einnahme zink feet to the top of the head in a human bodystanding erect. It is measured using a stadiometer usually in centimetres when using the metric system wikioedia,   or feet and inches hyman using the imperial system. A particular genetic profile in men called Y haplotype I-M is correlated with height. Ecological data shows that as the frequency of this genetic profile increases in the population, the average male height in a country also increases. When populations share genetic background and human growth hormone facts wikipedia factors, average height is frequently characteristic within the group.
Human height - Wikipedia
Human height or stature is the distance from the bottom of the feet to the top of the head in a human body , standing erect. It is measured using a stadiometer ,  usually in centimetres when using the metric system ,   or feet and inches when using the imperial system. A particular genetic profile in men called Y haplotype I-M is correlated with height. Ecological data shows that as the frequency of this genetic profile increases in the population, the average male height in a country also increases.
When populations share genetic background and environmental factors, average height is frequently characteristic within the group. The development of human height can serve as an indicator of two key welfare components, namely nutritional quality and health.
The study of height is known as auxology. For individuals, as indicators of health problems, growth trends are tracked for significant deviations and growth is also monitored for significant deficiency from genetic expectations. Genetics is a major factor in determining the height of individuals, though it is far less influential in regard to differences among populations. Average height is relevant to the measurement of the health and wellness standard of living and quality of life of populations.
Attributed as a significant reason for the trend of increasing height in parts of Europe are the egalitarian populations where proper medical care and adequate nutrition are relatively equally distributed.
Nations that consume more protein in the form of pork , dairy , eggs , and fish tend to be taller, while those that attain more protein from cereals tend to be shorter.
Changes in diet nutrition and a general rise in quality of health care and standard of living are the cited factors in the Asian populations.
Malnutrition including chronic undernutrition and acute malnutrition is known to have caused stunted growth in various populations. Height measurements are by nature subject to statistical sampling errors even for a single individual. The smooth 50th percentile male and female growth curves illustrated above are aggregate values from thousands of individuals sampled at ages from birth to age In reality, a single individual's growth curve shows large upward and downward spikes, partly due to actual differences in growth velocity, and partly due to small measurement errors.
For example, a typical measurement error of plus or minus 0. Note there is a discontinuity in the growth curves at age 2, which reflects the difference in recumbent length with the child on his or her back , used in measuring infants and toddlers and standing height typically measured from age 2 onwards.
Height, like other phenotypic traits, is determined by a combination of genetics and environmental factors. A child's height based on parental heights is subject to regression toward the mean , therefore extremely tall or short parents will likely have correspondingly taller or shorter offspring, but their offspring will also likely be closer to average height than the parents themselves.
Genetic potential and a number of hormones, minus illness, is a basic determinant for height. Other factors include the genetic response to external factors such as diet, exercise, environment, and life circumstances. Humans grow fastest other than in the womb as infants and toddlers , rapidly declining from a maximum at birth to roughly age 2, tapering to a slowly declining rate, and then during the pubertal growth spurt, a rapid rise to a second maximum at around 11—12 years for female, and 13—14 years for male , followed by a steady decline to zero.
On average, female growth speed trails off to zero at about 15 or 16 years, whereas the male curve continues for approximately 3 more years, going to zero at about 18— These are also critical periods where stressors such as malnutrition or even severe child neglect have the greatest effect. Moreover, the health of a mother throughout her life, especially during her critical period and pregnancy , has a role.
A healthier child and adult develops a body that is better able to provide optimal prenatal conditions. Thus, there is a cumulative generation effect such that nutrition and health over generations influences the height of descendants to varying degrees. The age of the mother also has some influence on her child's height.
Studies in modern times have observed a gradual increase in height with maternal age, though these early studies suggest that trend is due to various socio-economic situations that select certain demographics as being more likely to have a first birth early in the mother's life.
It has been observed that first-born males are shorter than later-born males. The precise relationship between genetics and environment is complex and uncertain.
A genome-wide association GWA study of more than , individuals has identified hundreds of genetic variants in at least loci associated with adult human height. This gives insights into the biological mechanisms underlying how these genetic variants affect overall height. As an example, 4 of the 7 loci identified for intracranial volume had previously been discovered for human height. The effect of environment on height is illustrated by studies performed by anthropologist Barry Bogin and coworkers of Guatemala Mayan children living in the United States.
In the early s, when Bogin first visited Guatemala , he observed that Mayan Indian men averaged only Bogin took another series of measurements after the Guatemalan Civil War , during which up to a million Guatemalans fled to the United States.
He discovered that Maya refugees, who ranged from six to twelve years old, were significantly taller than their Guatemalan counterparts. The Nilotic peoples of Sudan such as the Shilluk and Dinka have been described as some of the tallest in the world. Dinka Ruweng males investigated by Roberts in —54 were on average As the study points out, Nilotic people "may attain greater height if privileged with favourable environmental conditions during early childhood and adolescence, allowing full expression of the genetic material.
The tallest living married couple are ex-basketball players Yao Ming and Ye Li both of China who measure They married in Shanghai , China, on 6 August In Tibet, the khampas are known for their great height. The people of the Dinaric Alps mainly South Slavs Montenegro and East Herzegovina are on record as being the tallest in the world, with a male average height of Growth in stature, determined by its various factors, results from the lengthening of bones via cellular divisions chiefly regulated by somatotropin human growth hormone hGH secreted by the anterior pituitary gland.
Somatotropin also stimulates the release of another growth inducing hormone Insulin-like growth factor 1 IGF-1 mainly by the liver. Both hormones operate on most tissues of the body, have many other functions, and continue to be secreted throughout life; with peak levels coinciding with peak growth velocity, and gradually subsiding with age after adolescence.
The bulk of secretion occurs in bursts especially for adolescents with the largest during sleep. The majority of linear growth occurs as growth of cartilage at the epiphysis ends of the long bones which gradually ossify to form hard bone.
The legs compose approximately half of adult human height, and leg length is a somewhat sexually dimorphic trait, with men having proportionately longer legs.
Some of this growth occurs after the growth spurt of the long bones has ceased or slowed. The majority of growth during growth spurts is of the long bones. Additionally, the variation in height between populations and across time is largely due to changes in leg length. The remainder of height consists of the cranium. Height is sexually dimorphic and statistically it is more or less normally distributed , but with heavy tails.
Most intra-population variance of height is genetic. Short stature and tall stature are usually not a health concern. If the degree of deviation from normal is significant, hereditary short stature is known as familial short stature and tall stature is known as familial tall stature. Confirmation that exceptional height is normal for a respective person can be ascertained from comparing stature of family members and analyzing growth trends for abrupt changes, among others.
There are, however, various diseases and disorders that cause growth abnormalities. Most notably, extreme height may be pathological, such as gigantism resulting from childhood hyperpituitarism, and dwarfism which has various causes. Rarely, no cause can be found for extreme height; very short persons may be termed as having idiopathic short stature.
An even rarer occurrence, or at least less used term and recognized "problem", is idiopathic tall stature. This treatment involves the injection of pure growth hormone into thick tissue to promote growth.
Certain studies have shown that height is a factor in overall health while some suggest tallness is associated with better cardiovascular health and shortness with longevity. Nonetheless, modern westernized interpretations of the relationship between height and health fail to account for the observed height variations worldwide.
These evolutionary pressures result in height related health implications. While tallness is an adaptive benefit in colder climates such as found in Europe, shortness helps dissipate body heat in warmer climatic regions. At the extreme end, being excessively tall can cause various medical problems, including cardiovascular problems, because of the increased load on the heart to supply the body with blood, and problems resulting from the increased time it takes the brain to communicate with the extremities.
For example, Robert Wadlow , the tallest man known to verifiable history, developed trouble walking as his height increased throughout his life. In many of the pictures of the later portion of his life, Wadlow can be seen gripping something for support. Late in his life, although he died at age 22, he had to wear braces on his legs and walk with a cane; and he died after developing an infection in his legs because he was unable to feel the irritation and cutting caused by his leg braces.
Sources are in disagreement about the overall relationship between height and longevity. Samaras and Elrick, in the Western Journal of Medicine, demonstrate an inverse correlation between height and longevity in several mammals including humans.
A study done in Sweden in has shown that there is a strong inverse correlation between height and suicide among Swedish men. A large body of human and animal evidence indicates that shorter, smaller bodies age slower, and have fewer chronic diseases and greater longevity.
For example, a study found eight areas of support for the "smaller lives longer" thesis. These areas of evidence include studies involving longevity, life expectancy, centenarians, male vs. They all support the conclusion that smaller individuals live longer in healthy environments and with good nutrition. However, the difference in longevity is modest. Several human studies have found a loss of 0.
But these findings do not mean that all tall people die young. Many live to advanced ages and some become centenarians. There is a large body of research in psychology, economics, and human biology that has assessed the relationship between several seemingly innocuous physical features e. In most occupational fields, body height is not relevant to how well people are able to perform, but nonetheless has been found to correlate with their success in several studies, although there may be other factors such as gender or socioeonomic status that explain this.
A demonstration of the height-success association can be found in the realm of politics. In the United States presidential elections, the taller candidate won 22 out of 25 times in the 20th century. These examples, however, were all before modern forms of multi-media, i. Further, growing evidence suggests that height may be a proxy for confidence, which is likewise strongly correlated with occupational success.
In the years since the midth century, the average human height in industrialised countries has increased by up to 10 centimetres 3. In the eighteenth and nineteenth centuries, people of European descent in North America were far taller than those in Europe and were the tallest in the world.
In the late nineteenth century, the Netherlands was a land renowned for its short population, but today its population is among the world's tallest with young men averaging The estimated mean height of English, German, and Scottish soldiers was American-born colonial soldiers of the late s were on average more than 7.
Average height of Americans and Europeans decreased during periods of rapid industrialization, possibly due to rapid population growth and broad decreases in economic status. Data derived from burials show that before , the mean stature of males and females in Leiden, Netherlands was respectively