Enamel is hardest substance in the human body.
61
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
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Your thumb is about the same size as your nose.
124
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22