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
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
The human sigh acts as a physiological reset button.
23
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
You can hear the blood flowing through your ears if you find a quiet place and cover them tightly.
17
In 30 minutes, the average body gives off enough heat (combined) to bring a half gallon of water to boil.
199