Enamel is hardest substance in the human body.
61
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
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
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
Every year your body replaces 98% of your atoms.
119
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