Your body is creating and killing about 2.4 million red blood cells per second.
17
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
Enamel is hardest substance in the human body.
61
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
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Yawns are more contagious among people with closer relationships.
163