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
The average sperm cell swims at 8 inches per hour.
76
Enamel is hardest substance in the human body.
61
Chewing gum boosts your brain power.
285
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
The human brain doesn't stop developing until about 25 years old.
102
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266