Post by Lone Wanderer on May 6, 2018 19:08:31 GMT
Source #1: Human height has its limits
Limits, you bet, says University of Chicago organismal biologist and anatomist Michael LaBarbera. While it's true average heights have gone up in the last 150 years, probably due to better nutrition (in terms of balanced diets, not caloric intake), folks in North America and Europe at least have probably just about peaked out.
In fact, Nature imposes a fundamental stature-cap: Mammals in general load their bones to about a quarter of their breaking strength during routine activities. If you doubled height, bone cross-sectional area would increase fourfold (radius squared), while weight (volume) increases eightfold (2 x 2 x 2)! Our bones would be overloaded, and breaks would be commonplace.
Bad as this sounds, things would actually be even worse, says LaBarbera: 12-foot-tall humans would be prone to collapsed arches, bad knees and excruciating back problems; 18-foot tall humans would be immobilized.
So, height limits, absolutely. But fat chance we've already peaked in body girth.
Source #2: How tall can a human grow?
Normally, the growth of our bones is limited by our sex hormones. A good burst of sex hormones at the right time tells the ends of our bones to stop growing. In acromegalic gigantism, as the tumour grows, it destroys cells in the pituitary gland that stimulate the release of sex hormones. The bones, therefore, never get the signal to stop growing.
But surely there must be a limit to a person's height? John Wass, a specialist in acromegalic gigantism at the University of Oxford, reckons it would be impressive to survive for long if you grew taller than 9ft.
First, high blood pressure in the legs, caused by the sheer volume of blood in the arteries, can burst blood vessels and cause varicose ulcers. An infection of just such an ulcer eventually killed Wadlow.
With modern antibiotics, ulcers are less of an issue now, and most people with acromegalic gigantism eventually die because of complications from heart problems. "Keeping the blood going round such an enormous circulation becomes a huge strain for the heart," says Wass.
Limits, you bet, says University of Chicago organismal biologist and anatomist Michael LaBarbera. While it's true average heights have gone up in the last 150 years, probably due to better nutrition (in terms of balanced diets, not caloric intake), folks in North America and Europe at least have probably just about peaked out.
In fact, Nature imposes a fundamental stature-cap: Mammals in general load their bones to about a quarter of their breaking strength during routine activities. If you doubled height, bone cross-sectional area would increase fourfold (radius squared), while weight (volume) increases eightfold (2 x 2 x 2)! Our bones would be overloaded, and breaks would be commonplace.
Bad as this sounds, things would actually be even worse, says LaBarbera: 12-foot-tall humans would be prone to collapsed arches, bad knees and excruciating back problems; 18-foot tall humans would be immobilized.
So, height limits, absolutely. But fat chance we've already peaked in body girth.
Source #2: How tall can a human grow?
Normally, the growth of our bones is limited by our sex hormones. A good burst of sex hormones at the right time tells the ends of our bones to stop growing. In acromegalic gigantism, as the tumour grows, it destroys cells in the pituitary gland that stimulate the release of sex hormones. The bones, therefore, never get the signal to stop growing.
But surely there must be a limit to a person's height? John Wass, a specialist in acromegalic gigantism at the University of Oxford, reckons it would be impressive to survive for long if you grew taller than 9ft.
First, high blood pressure in the legs, caused by the sheer volume of blood in the arteries, can burst blood vessels and cause varicose ulcers. An infection of just such an ulcer eventually killed Wadlow.
With modern antibiotics, ulcers are less of an issue now, and most people with acromegalic gigantism eventually die because of complications from heart problems. "Keeping the blood going round such an enormous circulation becomes a huge strain for the heart," says Wass.