For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Yawns are more contagious among people with closer relationships.
163
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
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your heart will pump about 212 million liters in its lifetime.
26
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 human body contains over a billion miles of DNA.
147
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149