Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Every year your body replaces 98% of your atoms.
119
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
Your body is creating and killing about 2.4 million red blood cells per second.
17
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55