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
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Enamel is hardest substance in the human body.
61
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
The average sperm cell swims at 8 inches per hour.
76
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193