Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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 your DNA was stretched out it would reach to the moon 6,000 times.
256
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Every year your body replaces 98% of your atoms.
119
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
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