Men grew faster than women in the last century, study says

The size of humans has increased over the past century thanks to better health and nutrition — but this change has not occurred equally among men and women, according to a new study published Wednesday in the journal Biology Letters. Men grew in height and weight at more than twice the rate of women.

Researchers from Italy, the United States and the United Kingdom analyzed data provided in 2003 by the World Health Organization (WHO) on the height and weight of more than 100,000 people in 69 countries. The authors of study they also used data from the Human Development Index (HDI), which measures national levels of human well-being.

The team found that each 0.2 increase in HDI resulted in an increase in height of approximately 1.68 centimeters for women and 4.03 centimeters for men, as well as an average weight gain of 2.70 kilograms for women and 6 .48 kilograms for men.

The trend was also confirmed when evaluating data from the World Bank’s Gini Index, which measures national levels of income inequality, for 58 countries between 2000 and 2006.

Greater inequality was associated with decreases in height and weight. Each unit increase in the Gini was associated with an average reduction in height of approximately 0.14 centimeters in women and 0.31 centimeters in men, and an average decrease in weight of approximately 0.13 kilograms for women and 0.39 kilograms for men. men, according to the study.

While one might think that more developed countries could also simply have genetically higher ethnic populations, “we believe this is not the case,” said study co-author and environmental physiologist Lewis Halsey, a professor at the University of Roehampton who leads the Behavior and Energetics at the University of Roehampton in London.

That’s because researchers found a similar trend when analyzing a compilation of adult height data from just one country: the United Kingdom.

By analyzing the heights of 49,180 men and women aged 23 to 26 from several British studies published between 1905 and 1958, they found that the average height of women increased by 0.25 centimeters every five years, while that of men increased by 0.69 centimeters. .

So what’s behind the disparity? “This is one of the first studies to make a connection between humanity’s evolution driven by sexual selection in combination with the effects of the environment on our phenotype, so how we present ourselves, how we characteristically look,” Halsey told CNN .

Size matters when choosing a partner

Halsey attributes the difference in growth rate between men and women to sexual selection. In the past, taller, heavier men tended to be stronger, allowing them to tower over other men, gaining more access to women and passing on their height genes, he explained.

However, even today, “women tend to prefer taller men,” he said, while, “in contrast, women’s height is not as important. So, to put it simply, men don’t often say, ‘Oh, I only like tall women.'”

“It’s a good cross-country study that basically confirms a well-known rule about sex differences in ‘ecosensitivity’,” said Professor Bogusław Pawłowski, head of the Department of Human Biology at the University of Wrocław in Poland, who was not involved in the study. study, to CNN by email.

“As the ecological or economic situation improves and there is better access to resources, males gain more biological benefits than females. It’s exactly the opposite when resources are scarce (males ‘suffer’ more than females).”

The “tallest man norm is something that occurs in Western countries (but also in many Asian countries),” Pawłowski said. “This means that in these populations (a) male height is an important aspect of a male’s attractiveness in the human mate market.”

Health monitoring

The variation in height between individuals of the same sex was smaller in countries with better living conditions. And, as observed in the United Kingdom, within a specific country’s population, height differences among men were smaller than among women as living conditions improved over time.

This is because men, being larger than women, “need more energy, they develop longer” and, especially because they have more muscle, their tissues are “metabolically a little more active,” Halsey said.

This means that for male growth, “it takes longer and is more costly, but this makes the male body more vulnerable to disturbances, to problems, to environmental influences” such as disease, he added.

Therefore, when there is a stressful environment with a greater burden of disease, men’s size is much more affected than women’s, he explained.

Because men’s size is more sensitive to living conditions than women’s, the study authors concluded that male height and height differences between the sexes “may be especially useful biomarkers for tracking population changes in health.”

Halsey added that the study shows that any trait that is more prominent in one sex than the other can be affected by a more demanding environment.

Study: Men and women’s brains age differently

This content was originally published in Men grew faster than women in the last century, says study on the CNN Brasil website.

Source: CNN Brasil

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