It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Your thumb is about the same size as your nose.
124
The human body contains over a billion miles of DNA.
147
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
The average sperm cell swims at 8 inches per hour.
76
One human hair can support 3 ounces.
191