Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
If you are cold you are more likely to be hungry because you use energy to keep warm.
144
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
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
When you take a step, you are using up to 200 muscles.
885
The human body contains over a billion miles of DNA.
147
Your heart will pump about 212 million liters in its lifetime.
26
Yawns are more contagious among people with closer relationships.
163