For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Your heart will pump about 212 million liters in its lifetime.
26
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 doesn't stop developing until about 25 years old.
102
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
The average sperm cell swims at 8 inches per hour.
76
The largest cell in the human body is the female egg and the smallest is the male sperm.
682