How Big Can A Person Get?

People have been getting bigger as time has progressed. 150 years ago, the average person was 10cm shorter than the average person today. Better nutrition and medical care early in life lets us take advantage of our genes that control how big we can grow. But how big can we get? When will the average human height stop growing or will it? The genes that control out growth doesn’t get much higher than 7’6”. Some people with disorders like tumors near the pituitary gland in the brain can experience accelerated growth, and for a longer time. The tallest person ever, Robert Wadlow, was 8’11” tall.

Robert Wadlow
Robert Wadlow and his Mother
Image from Wikimedia Commons

It turns out the average height right now is probably near the limit. By manipulating the genes responsible for controlling out height, we may be able to add an extra 6 inches to the average, but over that, we would most likely reach the limit. To regularly produce people over eight feet tall, they would most likely have to be a different shape from humans. This is because of the square-cube law. This law states that as a shape grows, its volume increases at a greater rate. If we make something ten times larger, sure it’s taller and bigger, but the surface area of the object is 100 time larger, and its volume is 1000 time larger. Because weight is related to volume, the object is 1000 time heavier, but only has 100 times the surface area to support it. If you wanted to be really big, you would need bones that were made of something harder or bones that were monstrously big.

Even if you solved the problem of muscle and bone strength, there would still be other problems. For one, you heart wouldn’t be big enough to keep blood pumping through your body. Animals can grow that large because their bodies are of different proportions. The biggest animal ever to live on the surface of the Earth, the Giraffatitan, was 44 to 66 tons. Any larger than this, and in order to survive, the animal would need more buoyancy to counteract its weight than air could provide. This is why blue whales can grow so big. The biggest blue whale ever measured was 390,000 pounds. This is the heaviest animal found on Earth. It might be the biggest animal ever found. Animal size is limited by simple geometry and Earth’s gravity. If we were on another planet, this would be a lot different. Mars’s gravity would let animals grow way bigger.

I think it is very interesting that we humans will not get much bigger. We will never be giants of nine or ten feet tall. We could try to make our bones stronger and therefore, we would be taller, but I don’t see that happening anytime in the near future. The size you can grow to also depends on the ecosystem you live in. We have discussed ecosystems in class and I think it’s interesting how living in water or a place of lower gravity could really affect your size. We could grow bigger, I guess, by becoming mermaids.


This entry was written by Steve G. and tagged . Bookmark the permalink.

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