Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your body is creating and killing about 2.4 million red blood cells per second.
17
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
One human hair can support 3 ounces.
191
The average sperm cell swims at 8 inches per hour.
76
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
The largest cell in the human body is the female egg and the smallest is the male sperm.
682