It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Early American humans hunted car-size armadillos and used their shells for houses.
12
Only humans shed emotional tears.
331
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The human brain doesn't stop developing until about 25 years old.
102