Yawns are more contagious among people with closer relationships.
163
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Your body is creating and killing about 2.4 million red blood cells per second.
17
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Your heart will pump about 212 million liters in its lifetime.
26
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
It takes about 20 seconds for a red blood cell to circle the whole body.
102