The cartilage between our bones gets condensed by sitting, standing and other daily activities as the day goes on thus making us a tad shorter at the end of the day!!
Sidebar: This incredibly tall gentleman that you see pictured here is Bao Xishun who is now the world's 2nd tallest man coming in at an impressive 7"9 inches!!
That's pretty interesting! I saw this TLC special, and they showed some of the tallest kids in the world. there was this girl who measured at 7 foot 1, and she's only 16!