For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Enamel is hardest substance in the human body.
61
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Our Right Lungs takes more air than our left lung.
194
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22