For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Your thumb is about the same size as your nose.
124
The average sperm cell swims at 8 inches per hour.
76
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Every year your body replaces 98% of your atoms.
119
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18